Kim Daeyeol

The Social and Cultural Presence of Buddhism in the Lives of Confucian Literati in Late Chosŏn: the Case of Tasan 

Keywords: Confucianism, Buddhism, Late Chosŏn, religious plurality, cultural interaction, Chŏng Yagyong

Our understanding of the relationship between Confucian literati and the Buddhist world of the late Chosŏn period has been biased not only by the dominant ideological setting of the period but also by our own contemporary perspective. This article attempts to extend the examination of this relationship away from ideological, religious and philosophical perspectives to a sociological and anthropological one. By retracing and reorganizing some anecdotes of the life of Tasan, it draws attention to the evolution of that well-known Confucian scholar's attitudes towards Buddhism and analyzes some factors behind his drawing closer to the Buddhist world.

Introduction

It is well known that during the Chosŏn dynasty Korean society was dominated by Confucian ideology, that Buddhism was rejected for being a heretic teaching, and that monks were driven out to remote mountain temples by the state. However, it is also known that some Confucian literati appreciated and socialized with the Buddhist Kim Daeyeol (dkim@inalco.fr) is Maître de Conférences (Lecturer) at the Institut National des Langues et Civilisations Orientales, Paris  Research for this paper was supported by an AKS Fellowship Program for Korean Studies. I would like to thank Prof. Boudewijn Walraven for his judicious comments on this paper and Sean Moores for his careful proofreading of the English.

world. 1 Though seemingly contradictory, these two facts reveal that during this period "Confucian" literati had various ways of perceiving the Buddhist world; and that social and cultural barriers between the two worlds varied according to the public or private situation of each individual, and were at times much less formidable than what certain ideological and conventional discourses would have us imagine.

In this article, I will problematize commonly received and still influencial assumptions related to this issue. The main problem is that, without considering the dimension of personality or the evolutionary aspect of attitudes, they rigidly apply a simplified and fixed ideological framework to individuals of a certain social group (i.e. the Confucian literati). However, an individual's social "belongingness" must be nuanced to the context of his own life, and socio-cultural complexity has to be taken into account. Some new approaches are thus needed. With this in mind, I will provide a counter-example to such viewpoints through a case-study of Chŏng Yagyong (1762-1836), also known under his penname Tasan. Tasan's relationship with Buddhism is 1 The expression "Buddhist world" here refers not only to the Buddhist belief system as a religious object and its community of believers, but also to that ensemble of diverse cultural elements related to Buddhism that one can enjoy even without religious faith: Buddhist monasteries as an anthropogeographical environment, monks' dietary tranditions as culinary culture, and sūtras or temple gazetteers a literary texts. See below.

well known and has been the subject of a number of studies. 2 However, in my opinion, these studies seem generally to overlook the development of this relationship. One of the focal points of this article is to underline those socio-cultural factors that generate dynamism and gradually transform the relationship between an individual and religious or cultural traditions. I will hence reprocess the example of Tasan so as to highlight the social and cultural context and psychological mechanisms that seem to have contributed to changing his relationship with Buddhism over time.

At the outset I feel it necessary to mention and clarify, albeit briefly, two points that might lead to doubts regarding the soundness of this sort of approach. The first concerns the study of one person. Though I will examine one individual, I will not extrapolate the example of Tasan to all others in the socio-cultural group to which he belonged. The aim of this paper is to focus upon the social and cultural aspects of a single individual case, and to examine its context and evolution. This work should ideally be supplemented with other such case studies, however, this goes beyond the scope of the 2 A pioneering study was made by Yi Ŭlho, "Yubul sanggyo ŭi myŏn esŏ pon Chŏng Tasan," in Paek Sŏnguk paksa songsu kinyŏm pulgyohak nonmun chip, ed. Paek Sŏng-uk paksa songsu kinyŏm saŏp wiwŏnhoe (Seoul: Tongguk munhwasa, 1959), pp. 705-730. More recently, studies have been focused on his relation with Buddhism during his exile period at Kangjin, for example: O Kyŏnghu, "Chosŏn hugi pulgyosa ch'ansul kwa Taedong sŏngyo ko," Han'guk sasang kwa munhwa 35 (2006):. 81-112. Chŏng Min has published many articles on the subject, exploring in particular new materials discovered from Buddhist and family collections, for example: Chŏng Min, "Han'guk kyohoesa yŏn'guso sojang Tasan ch'inp'il sŏganch'ŏp Maeok sŏgwe e taehayŏ," Kyohoesa yŏn 'gu 33 (2009): 539-568. present article. The second point concerns the materials used in the present study. I quote Tasan's writings from a variety of different records, such as his letters, travelogs, encomiums and poems. However, the use of poems as historical sources in the study of social and cultural issues sometimes gives rise to doubts, since they are normally considered as imaginative in nature and of only esthetic interest. However, this depends upon the poet's view as to just what a poem is. For Tasan, a poem expresses what it means to be human and can contribute to social relief. 3 This is why his poems are often nothing but descriptive, narrative and factual records. 4 Being clearly dated, they can serve as reliable historiographic material, just like a diary, through which one can trace the factual development of certain aspects of his life. 5 But more generally speaking, we can legitimately consult artistic products as part of historical and sociological analysis because any form of human creation is a social product, reflecting its cultural and social 3 "The root of all poetry is situated in the moral principles observed between parents and children, sovereign and subject, and husband and wife. Sometime it heightens their happiness; sometime it expresses their resentment in these relationships. Secondly, [it is based on] concern about society and providing relief to the people. It is after having the intention to aid the helpless and to save poor people, after having felt lost and hurt but not having the heart to abandon them, that one can compose a poem."

凡詩之本。在於父子君臣夫婦之倫。或宣揚其樂意。或導達其怨慕。其次憂世恤民。常 有欲拯無力。欲賙無財。彷徨惻傷。不忍遽捨之意。然後方是詩也。"Si yang'a" 示兩兒,
Tasan simunjip 茶山詩文集, vol.21. 4 See Yi Kihyŏn, "Tasan ǔi sahoesi yŏn'gusŏsajŏk sahoesi rǔl chungsim ǔro," Hanminjok munhwa yŏn'gu (1999); Yun Chaehwan, "Tasan sahoesi ǔi sŏngkyŏk pyŏnhwa kŏmt'o," Hanminjok ŏmunhak (2007); Yun Kyŏngsu, "Tasan ǔi sahoesi yŏn'gusŏsajŏk sasilsŏng ǔl chungsim ǔro," Han'guk sasang kwa munhua (2012). background and context. 6

General problems

Let us return to the starting point: the problem of the relationship between so-called "Confucian" literati and Buddhism. A great deal of ambiguity still surrounds this issue.

While the "separation" theory was still widely accepted up until the 1980s, a number of studies on the interaction between these two worlds have recently been published.

Approximately twenty seventeenth and eighteenth-century personages from the "Confucian" side have thus far been studied from the perspective of their relations with the Buddhist world. 7 However, these studies have generally been confined to literary institutional perspectives between the elite class and the Buddhist world has yet to emerge as an object of research.

The main difficulties in this matter arise from the sources used in such studies. It can be observed that the Buddhist side, in order to survive or to be acknowledged, made a more explicit effort to establish relations with the Confucians in the late Chosŏn period.

There is considerable amount of documentation available that details such contacts, as a number of related studies have shown. 8 However, considering that Buddhists had much to gain in terms of identity and legitimacy through a relationship with the hegemonic group, one may naturally suspect their records of internal bias in this respect. On the other hand, official documents and Confucian literature deliberately omit reference to any relationship with the Buddhist world, in order to preserve its cultural hegemony or elude political and social supervision. This absence, combined with the critical attitude of its formal and conventional discourse, has been interpreted as evidence of the Confucian elite's break with Buddhism.

To these difficulties is added the way traditional scholarship has viewed the interaction between the Confucian and Buddhist worlds through polarized and sclerotic social categories sucha as Confucian yangban vs. heretical and humble monks. However, such broad social groups, generally perceived as being monolithic, should in fact be sub-divided according to criteria other than social status, such as intellectual activity or cultural preferences. It goes without saying that having the same social status does not necessarily mean having the same intellectual or cultural preferences and attitudes. Subgroups from each of the two sides, sharing intellectual and cultural affinities, could very well have communicated and interacted with each other. In an article published five years ago in this journal, Boudewijn Walraven pointed out the need to re-examine the preconceived idea that Buddhism in late Chosŏn had degenerated and fallen into outright superstition, remaining active only at the lower social levels rather than amongst the dominant and literate class. 9 He attributed this attitude principally to the ideals of colonial modernity. His main argument was that in so far as there had been a popularization of Buddhism at this time, it can also be understood as an assimilation by commoners of a form of elite Buddhism. More generally, "what is needed," Walraven writes, "is a much more nuanced view of the position of Buddhism in Chosŏn society that accounts for both the positive as well as the negative aspects within a comprehensive framework that includes a more sophisticated acknowledgement of social differentiation, and goes beyond the simple dichotomy of the elite versus the 9 Boudewijn Walraven, "A Re-Examination of the Social Basis of Buddhism in Late Chosŏn Korea,"

Seoul Journal of Korean Studies 20, no. 1 (June 2007), 1-20. people." 10 He demonstrates this argument through the relationships some members of the higher strata of society had with the Buddhist world. 11 Nowadays, in academic circles at least, it seems to be admitted that during the late Chosŏn period there was interaction between Confucians and Buddhists. "Not only did Buddhism exercise an influence on the peasantry during the late Chosŏn period," one historian of Korean religions has written, "it also had an influence sub rosa on the Confucian literati." 12 According to this view, some positive aspects of the Buddhist world progressively came to the fore, along with criticism of orthodox Korean tradition inspired by Zhu Xi's school of thought, and this formed the context in which the Buddhist world gradually emerged out of its socio-cultural marginalization. 13 How and to what extent did this change take place? If some consider such exchanges as being rather modest, 14 others point out that some conventional interaction between Buddhist monks and Confucian literati officials was based on a continuous and close 10 Ibid., 4.

11 With respect to this issue, another problematic notion is that of ideological attitudes and religious convictions. This will be discussed later in the section dconcerning the social functionalist viewpoint.

12 James Huntley Grayson, Korea, A Religious History (New York: RoutledgeCurzon, 2002), 139.

13 Kim Chunhyŏk, "Chŏngjo ǔi pulgyo insik pyŏnhwa," Chung'ang saron 16 (2002).

14 Yi Chongch'an, "Chosŏn chung hugi yu-bul si'in ǔi kyosŏp yangsang," Han'gugŏ munhak yŏn 'gu 48 (2007), 8. relationship.15 Some questions have thus arisen concerning this contact between the two groups. If there was some sort of relationship, then what form did it take? And if there was not, then how and to what degree was contact and exchange established? What kind of socio-cultural basis and environment was formed, and in what way did Confucian literati perceive it? Also, did this eventual contact between Confucians and Buddhists give rise to any changes in a Confucian's public and private life? These questions concerning the interaction between individuals and groups belonging to two different traditions are relevant to our understanding of social and cultural developments in the late Chosŏn period, a time when Confucian hegemony began to decline. 16 They can provide clues to Confucian literati attitudes, as well as their awareness of and reactions to the social and cultural changes of the period.

Viewpoints

In this article, I will seek to ascertain what coexistence between these two traditions (one hegemonic and the other marginalized but apparently with a large following) meant for the Confucian literati of the period. Interest in this question is not only inspired by the desire to re-establish certain historical facts about the relationship 10 between these two traditions, but more generally because a better undertanding of the coexistence and exchanges between such traditions may help shed light upon the cultural plurality of Chosŏn society, a plurality that served to stimulate its social and cultural dynamism. Hence, I suggest a change of perspective, so as to examine how and why interaction between these two groups was possible or impossible, how it was produced and evolved, as well as its social and cultural aspects, and what the Buddhist presence meant to the social and cultural environment of the literati. Sharing Walraven's view, my article aims to illustrate this question and open up more discussion of it. In particular, I will outline the cultural and social presence of the Buddhist world in a Confucian's life, as well as its evolution and consequences. In so doing, I hope to emphasize the need to consider the coexistence of, and encounters and exchanges between, the Buddhist and Confucian worlds, not from an ideological or political angle, which tends to highlight a doctrinal confrontation or reconciliation, but from a sociological and anthropological perspective, which allows for a more relevant observation of all aspects of their relationship and development, so as to understand in greater detail the society in which they both existed. Hence, the use in this article of the terms "Confucian's life" or "Buddhist world," which denote social and cultural dimensions, rather than "Confucianism" and "Buddhism," which connote an ideological or doctrinal dimension.

A Social Functionalist Viewpoint in Need of Revision

The negative perception of Buddhism, as referred to by Walraven, was until recently widely accepted. Twenty-five years ago, it was even provided an explanatory theory. In his 1987 article, Chŏng Ch'angsu proposed an analysis of the phenomenon of religious plurality in Chosŏn society from a functionalist viewpoint-relying mainly on the work of Talcott Parsons, and consolidating the idea that the Buddhist world was isolated from Confucian literati and limited to the lower classes of society.17 According to this theory, the reason why mutually conflicting cultural elements coexisted in society was that each of them played a role in social cohesion. And when, in an institutionalized value system dominated by Confucianism, "irrational" discrepancies did exist between norms which were meant to be followed and their actual observance, other religious beliefs helped to compensate for such shortcomings.

However, such mutual complementing was not durable. It had a temporary and limited character in that it worked only as a sort of "contingency plan" at a time when normalized and regularized action was irrelevant. Chŏng Ch'angsu thought that this could explain why, during the Chosŏn period, Buddhism became alienated from its metaphysical base, becoming a religious faith and practice aimed at praying for good fortune. 18 In this distribution of roles, in response to the need for social integration, different traditions coexisted on a sort of dominant-dominated basis. Chŏng proposed three such modes of coexistence. In the first type the state embraced, for its official ceremonies and publicly-supported events, religious faiths and practices which were compatible with Confucian ideology or the state's operating system (chedojŏk tonghwa). Some shamanic ritual offerings to supernatural beings were thus made at the Chosŏn court. However, Buddhism was not placed in this category. The second type refers to "selective acceptance according to affinity" (sŏnbyŏlchŏk suyong) with Confucian ideology. Geomancy (p'ungsu) was a prominent example of this type. As for Buddhism, Chŏng underlined that this "selective acceptance" appeared amongst a limited class of people. Buddhism was referred to more in the third type, concerning the question of "separate" or "subordinate acceptance" (pulli mit chongsokchŏk suyong), in which faiths and religious practices were separated and organized into a hierarchy of various classes.

According to Chŏng, this mode of coexistence resulted in two functional effects.

Firstly, when distinction was made between a superior male class as being Confucian and an inferior female class as being Buddhist or dedicated to other faiths: confined to 18 Ibid, 18. their feminine dimension, Buddhism and Shamanism could be introduced and practiced, thereby playing complementary roles even in the families of Confucian officials, without however entering into conflict with the social and political status of male members who embraced Confucian ideology. Secondly, it was by means of this coexistence that the separation and subordination of these "undesirable" faiths and practices were maintained amongst the lower strata of society. Thus connected to such strata, they continued to be viewed as an inferior form of culture.

However, it would seem appropriate to recall here certain limits to this theory, limits that Chŏng Ch'angsu himself acknowledged in his conclusion. In fact, he nuanced his explanation by means of three points. Firstly, there must be some factors that a social functionalist viewpoint cannot account for; secondly, his work deals with the relationship between Confucianism and other belief systems in a rather static and general manner; thirdly, his approach lacks an analysis of the relationship between "lower elements," such as Buddhism, p'ungsu geomancy or shamanistic beliefs.

Nevertheless, his approach provided a framework that has since been widely used by researchers, especially those interested in the education, socialization, or "Confucianization" of Chosŏn society.

Ideology versus Mentality

To his discussion concerning the limits of his research, I would add two more points.

First, there is the premise upon which his stance seems to be based: "Buddhism and Confucianism were antagonistic or incompatible in Chosŏn society." Of course, we can hardly deny that this was the case, when we consider the position of rulers, government officials and the social elite of the Chosŏn period, for whom the ideology of education and socialization was at stake. This was the case when it came to the political elite's socializing blueprints, the state's functioning and the moral discourses of the elite. What is more, Confucian scholars were for the most part seen as both ideologues and literati, and the history of Confucian intellectuals in general has largely been a question of thought and ideology. However, the relationship between these two cultural elements cannot be considered solely in terms of ideological conviction, as other aspects are obviously also important: local, social and family networks in particular, in which individuals and even families of the "higher classes" were in contact with the Buddhist world in various ways. A number of examples of this can be found in the aforementioned article by Walraven. As far as their relationship with the Buddhist world is concerned, their "mentalities" 20 and socio-cultural behavior have yet to be given their due place in historical research.

Neither should the historical depth of the relationship between Buddhism and Confucianism in Korean society be overlooked. Many efforts were made from the Silla period onwards to reconcile the two traditions, this despite their respective struggles for hegemony. Differences in their ultimate goals notwithstanding, there are significant points of convergence between the two, such as similarities in their approaches towards self-cultivation. 21 Some prominent figures are known to have crossed the boundary between the two traditions. During the sixteenth and seventeenth centuries, thanks to religious consolation for those affected by disasters and wars, Buddhist culture, which was already deeply enrooted in the "mentalities" of the Korean people, obtained a popular base and was able to extend its development in society. 22 Confucian literati cannot be excluded from the population amongst which it thus spread. 20 For a discussion on "ideology" and 'mentality," see Michel Vovelle, "Ideologies and mentalities," in

"Disciplinary Production" versus "Creative Consumption"

The relationship an individual can have with a religious tradition can be examined in various ways. The Buddhist world provides not only a belief system and social organization, but also all of the "cultural elements" one can enjoy either religiously or unreligiously. For example, besides a purely religious site, a monastery may also be regarded unreligiously as a place for sightseeing, a site of culinary culture (in the diet of Buddhist monks), and as repository of Buddhist canonical texts or temple gazetteers.

The expression "cultural elements" here refers to knowledge of both traditional practices and material heritage. When used in a religious context these elements carry a religious meaning; but they can also be used for other reasons and in other contexts. To "believe in a religion" and "have knowledge about a religion" are obviously two different things. It is also possible to abide by a certain type of traditional practice without believing in that practice's corresponding religious faith. As a result, the claim to be Confucian does not necessarily exclude the adoption or appropriation of Buddhist (or any other) cultural elements, and vice versa. In other words, and to quote Michel de Certeau, we have to distinguish between "disciplinary production" and "creative consumption" (or use). 23 We should also bear in mind that a certain perception of religion, based upon a certain religious tradition (Judeo-Christian) formed in the specific historical context of Western civilization, has defined it as being an exclusive credo, disregarding the possibility of its coexistence with other religious traditions. 24 The Dimension of Personality Another comment to make on Chŏng Ch'angsu's analysis is that his theory does not suppose the coexistence of Confucianism and Buddhism amongst the literati class. The dimension of personality, which is accounted for in the case of people of lower social strata, is not considered when it comes to the literati class. In other words, "irrational discrepancies" are taken for granted among common people but not among literati. In Chŏng's explanation, scholars seem to be viewed simply as ideological and socializing agents of the state, and not as individuals whose interests could overflow into spheres other than those of political or social obligations. For an individual, whoever he is, a religious tradition may be viewed as one of a number of different cultural models, and not always as a final or sole objective, it being possible to also pursue other cultural models that may be more fundamental. 25 The "complementary relationship," the first coexistence mode postulated in Chŏng Ch'angsu's explanation, can also be found amongst the literati class between Confucian and Buddhist cultures. In this sense, the third type of coexistence, "separate" and "subordinate" acceptance, which confines Buddhism to inferior classes and female groups, should be reconsidered. In fact, like Shamanic culture's complementary role vis-à-vis the Confucian world, Buddhist culture also might serve a complementary function to Confucianism, not just in a separate "inferior and female" class, but beyond that and by bearing upon the personalities of Confucian literati.26

The Presence of Buddhism in Tasan's Confucian World

To illustrate this through a concrete example, let us examine the case of Chŏng Yagyong intellectually open-minded. In his youth, he was interested in Christian doctrine. In terms of his relationship with Buddhism, it would seem that he gradually drew closer to it over the years. Towards the end of his life, he occasionally wrote as if he were a Buddhist himself. This article aims to show the influences Tasan received from the two different traditions and the social and cultural dynamism this involved, observing how and under what circumstances he evolved. As his life is well known, this article can introduce almost nothing new in terms of its details. It will, however, retrace and reorganize the details of that life so as to draw attention to aspects which may have previously been overlooked by researchers.

Familiar Surroundings, Pragmatic Interests, Favorable Impacts

During his youth, Tasan's relationship with the Buddhist world seems to have been rather pragmatic. He became gradually acquainted with the Buddhist world while visiting monasteries, where he sometimes stayed to study and thereby had the opportunity to meet monks. The first impression he had of such places was of their lofty, truth-searching atmospheres. His first well-documented encounter with the Buddhist world dates to the winter of 1775, when he was fourteen and visited Sujong monastery 水鐘寺, situated half-way up Ungil hill, five km. north of Tasan's birth place at Ch'och'ŏn 苕川 (or Sonae). 27 However, he also wrote that he had been visiting this monastery since his childhood, which leads us to infer that his first encounters with Buddhism started much earlier. 28 Apparently, the monastery made a more than agreeable impact on him. One poem discloses his determination to return there one day after having seen something of the world. After he married and moved to Seoul in 1776, Tasan visited this monastery every time he returned to his hometown. Moreover, in the winter of 1778, when he was seventeen years old, he spent forty days reading books in Tongnim monastery 東林寺 with his elder brother Yakchŏn. An extract of their conversation provides us a glimpse of the favorable impression they shared of monastic life. 29 This Buddhist environment, its utility and favorable impact upon him were constant factors throughout his life.

In 1782, when he was twenty-one years old, Tasan stayed in Pongŭn monastery 奉恩寺 in Seoul, again with his elder brother, to study for the kwagŏ examination. 30 After becoming a chinsa 進士, a classical literary licentiate, in the spring of 1783, Tasan stopped off for a short stay at this monastery while on his way back to his 27 "Yu Sujongsa" 游水鐘寺, Tasan simunjip, vol.1.

28 "Yu Sujongsa gi" 游水鍾寺記, Tasan simunjip, vol. 13.

29 "Tongnimsa Toksŏgi" 東林寺讀書記, Tasan simunjip, vol. 13. Tongnim monastery is in South Chŏlla province, near the town of Hwasun. Hyewŏn 慧遠, a monk Tasan knew, may have been at this monastery. See note 34 below. 32 "Suk Sujongsa" 宿水鐘寺, Tasan simunjip, vol.1. 33 In present-day South Chŏlla province.

34 "Pojo kuksa hwasang ch'an" 普照國師畫像贊, Tasan simunjip, vol.12. Manyŏn monastery is in South Chŏlla province, near both Hwasun and Tongnim monastery.

Yŏndam Yu'il 蓮潭有一 (1720-1799) in 1778. 35 Yu'il was also the master of monk Ch'oŭi Ŭisun 草衣意洵 (1786-1866), who later became one of Tasan's disciples.

Tasan was introduced to Yu'il by a monk named Hyewŏn 慧遠. The latter's surname was Chŏng 丁, the same as that of Tasan, and had known Tasan ever since visiting Ch'och'ŏn. 36 While still a youth, Tasan was already in contact with a number of monks and held some of them in high regard. In a poem dedicated to Yu'il, he expresses his respect for monks and his regret about divisions between Confucians and Buddhists.

...

So sad bringing forth detached thoughts

So many heroes and great figures living in seclusion

When there is no more distinction between self and object, here is the Way What a futile contention amongst Confucians and Buddhists! 37 35 "Chŭng Yuil sangin" 贈有一上人, Tasan simunjip, vol.1. 36 This account derives from an annotation Tasan himself made to the previously-quoted poem (see note 27). Monk Hyewŏn is reported to have been from Tongnim monastery. Cf. O Kyŏnghu, "Chosŏn hugi Taedun saji ǔi p'yŏnch'an," Han'guk sasangsahak 19 (2002), 353. In another poem ("Ŏk sŏkhaeng gi Hyejang" 憶昔行寄惠藏, Tasan simunjip, vol.5), a monk named Wŏnggong 苑公 is mentioned. In another annotation by Tasan himself, this monk is presented as Ch'ŏp'a taesa 靑坡大士 Hyewŏn 慧苑, having Chŏng 丁 as a surname, from Chŏnju 全州. Hyewŏn 慧遠 and Hyewŏn 慧苑 could be the same person. On the other hand, it is supposed that Tasan became acquainted with Yu'il thanks to another personal contact. Yu'il had the same master as Sŏlp'a Sangŏn 雪坡尙彦 (1707-1791).

Pŏnam Ch'ae Chegong 樊巖 蔡濟恭 (1720-1799), under whom Tasan studied, was close enough to Sŏlp'a Sangŏn to compose his epitaph. Cf. Ch'oe Pyŏnghŏn, "Tasan Chŏng Yagyong ǔi Han'guk Pulgyosa yŏn'gu," in Chŏng Tasan yŏn'gu ǔi hyŏnhwang (Seoul: Minǔn sa, 1985), 327; Chŏng Chonggu, "Tasan ǔi Pulgyogwan," Tasan hakpo 1 (1978), 214.

37 "Chŭng Yuil sangin" 贈有一上人, Tasan simunjip, vol.1.

Political Obedience vs. Personal Affinity

However, over a span of seven years, between 1783 and 1789, during his period as a student at Sŏnggyungwan, it would seem that he left no trace of his contacts with the Buddhist world, except for occasional visits to monasteries on his way back to his hometown. 38 This makes us feel that there must have been a break between Tasan's personal and affective life and the public and ideological sphere.

Tasan became a government official in the third month of 1789. From then on, writings about excursions to monasteries reappear. In the eighth month of that year, he went sightseeing with his father to Ŭnhae 銀海 monastery in Yŏngch'ŏn, Kyŏngsang province. 39 In the third month of 1790, when he was exiled for a short time at Haemi,40 he stayed one night at Kaesim 開心 monastery41 with the governor of T'ae-an county.42 However, his attitude towards the Buddhist world during this period is quite 38 In a series of poems ("Ch'och'ŏn sasisa hyo Changnamho sangsim naksa" 苕川四時詞效張南湖賞心樂事, Tasan simunjip, vol.1) composed in the early summer of 1786 in his hometown of Ch'och'ŏn to celebrate the view of the four seasons, we find "Hǔngbok-sa ch'ŏng'aeng" 興福寺聽鶯.

39 "Pae gagun yu Ŭnhae sa" 陪家君游銀海寺, Tasan simunjip, vol.1. Tasan wrote here that many officials had visited this monastery. typical of a Confucian official. In his "Answer to the question about men of ability," which he wrote in 1790, supposedly as a reply to an inquiry by King Chŏngjo, 43 he firmly rejects Buddhism as heresy. Indeed, Tasan resorts to anti-Buddhist arguments patterned by Neo-Confucian ideologists, a stand which contrasts with Chŏngjo's rather lenient attitude: In my humble opinion, your firm and resolute early edict banning coming and going through the capital city to these mu-shamans and monks, after repudiating them, must be hailed as marvelous imperial virtue and a brilliant historical event for which you should be praised. If you continue this way, our country will be blessed. 44 Such words notwithstanding, Tasan still displayed affinity for the monastic 43 Cho Sŏngŭl, Yŏyudang chip ŭi munhŏnhak chŏk yŏn'gu (Seoul: Hyean, 2004), 347.

44 "Injaech'aek" 人才策, Tasan simunjip, vol.8. atmosphere and his excursions to monasteries continued. In his writings, we find traces of visits to monasteries at least once a year between 1794 and 1799. On the fourth day of the fifth month, 1797, he composed poems while on an excursion with his brothers to the Ch'ŏnjin Buddhist hermitage 天眞庵 45 to enjoy the extremely palatable wild vegetables there. Here again we catch a glimpse of his contradictory attitude towards the Buddhist world. The poem implies that his interest in monasteries has a worthier reason than the mere pleasure of sightseeing and enjoying the beauty of monastic landscapes. In the winter of 1798, while he was staying at Chahyo monastery 資孝寺, he was tempted to reconcile Confucian culture, here materialized by the gŏmungo lute, with the Buddhist one, due to his keen realization of the value of monastic life. The proximity of the two cultures and their frequent encounters created an opportunity for harmony and fusion:

Disenchanted by noisy military music Intentionally, the chant for Buddha is tuned to the gŏmungo lute's notes 47 45 In present-day T'oech'on-myŏn, Kwangju-si, Kyŏnggi province.

46 "Sanjung kanghoe" 山中感懷, Tasan simunjip, vol.3.

Immersion in the Buddhist world for Eighteen Years

From the time of his exile to Kangjin (1801), Tasan made friends with local monks on a personal basis as well as for more elaborate cultural exchanges. Alone and destitute, Tasan found solace in meeting this learned group capable of sharing and enjoying a common intellectual horizon with him, while the monasteries provided him with a familiar and secure environment. This is the first distinctive feature of this period of Tasan's life that should be taken into account. Secondly, through such direct personal exchanges and experiences over an extended period of time, his viewpoint on the divisions between the Confucian and Buddhist worlds began to shift. In the meantime, due to the conflict between political and social restraints on the one hand, and his own personal aspirations on the other, his attitude towards Buddhism became more ambiguous. In other words, without actually converting to Buddhism, Tasan began to have a more positive perception of it and partially accepted it in his life. He became better disposed towards Buddhist culture and its way of life. Thirdly, he found himself making important cultural contributions to the Buddhist world. Furthermore, he ended up including monks in his own social networks.

In many aspects, Tasan's life in Kangjin seems to have been a long interlude of 47 "Ya yu chahyosa" 夜游資孝寺, Tasan simunjip, vol. 3. residing in a purely Buddhist world, during which he became freely assimilated to it. In the spring of 1803, a year and a half after his exile, he wrote the following poem for a monk: monks, drinking and sharing writings with them, while monks also visited Tasan's residence and helped him with such things as preparing meals.

An Empathic Experience of Buddhist Life

On the 17 th of the fourth month, 1805, Tasan went to Paengnyŏn monastery 白蓮寺, where he met Aam Hyejang 兒庵惠藏 (1772-1811) for the first time. Among all the monks he met, it was Hyejang who became particularly close to Tasan, who in turn highly appreciated and praised Hyejang's exceptional talents and lofty asceticism.

Hyejang followed him with great sincerity. Tasan's encounter with this monk, one of the greatest Sŏn monks of the day, provided him with a certain direction, vitality and even convenience during his life in exile. In the poems Tasan exchanged with Hyejang, many Buddhist terms are used. In the following poem, Tasan appears to be on the verge of converting to Buddhism. Nonetheless, consciousness of being a bureaucrat from a Confucian and anti-Buddhist government in spite of his exile, he subsequently added the following clarification, as if he were trying to erase suspicions concerning any possible intention of converting; something which could be misconstrued by the Confucian group hostile towards him: I asked Hyejang to compose and recite poems expressing his feelings about mountain life.

And as time went by, I found myself inclining towards his feelings, figuring out how I would fare if I were in his situation. Thus, on behalf of him to express his feelings, I took the brush to write and it amounted altogether to twenty Sǒn poems. Unexpectedly, because of my exile and the dire poverty it brough, time and again I felt as if it was me living retired in the serene place,. It is not that I admired their way of life but rather that I loathed hearing roosters crowing and dogs barking in the midst of other disturbing noises as I reflected to myself, trudging along in the dusk towards a far-off destiny. It was quite natural for me to like and desire their way of life. 50 What most catches our attention in this extract is the fact that Tasan was thinking of and experiencing Buddhist practice in the shoes of a Buddhist monk. As is well-known, an empathic experience with other people leads to a more profound understanding of them.

"Both a Sŏn Monk and a Versed Confucian:" A Form of Syncretism?

Tasan even brought together the poems and letters he exchanged with Hyejang under the title "Record of Looking at the Moon" (Kyŏnwŏl ch'ŏp 見月帖). A Buddhist nuance is clearly noticeable in this title. In their exchanges, Tasan supposedly talked about the Book of Odes (Sigyŏng 詩經), the Book of Documents (Sŏgyŏng 書經), and the Book of Changes (Yŏkkyŏng 易經), whereas Hyejang apparently talked about the Flower Garland Sūtra (Hwaŏmgyŏng 華嚴經), the Sūtra of the Heroic March (Nŭngŏmgyŏng 楞嚴經), and the Sūtra of Perfect Enlightenment (Wŏngakkyŏng 圓覺經). Tasan wrote the calligraphy on the cover of the Flower Garland Sūtra, borrowed the Sūtra of the Heroic March to read, while Hyejang borrowed Chinese classics to read. In this way, Tasan built up his knowledge about Buddhism. He took a keen interest in Hyejang's exceptional talents and advised him to pursue poetry and to turn to Confucianism as well:

Turn around your Buddhistic cart and Knock on the door of the Six [Confucian] Classics.

No better way

Than following the Yellow Emperor, Yao and Shun forever 51 [1806] At the same time, Tasan found himself becoming sincerely attached to the Buddhist way of life, as he was growing accustomed to living in remote regions, making the acquaintance of monks and dwelling in monasteries.

Musing over the events vividly remembered yesteryear during the King's Chaegŏ 52 retreat What a lonely king's place in the Eastern Tower On the 13 th day of the fifth month, my heart ached, my eyes, utterly-dry, were tearless [from crying over the king's mortal remains].

That day I put on a ritual cap, but rather now Will I follow the turning cart [wheels of Buddhism] for the remainder of my life. 53 Tasan's friendship with Hyejang continued until the latter's death. However, Hyejang was not the only monk Tasanbefriended. Other monks also assisted Tasan in his remote and mountainous dwelling place. He also made excursions to monasteries and discussed the sūtras with other monks. Some poems written during this period allude to his circle 51 "Owŏl ch'il il yŏ chae Poǔn sanbang Chang gong hyu chu sang kwa huǔi ya nyŏm Chuyŏk kam yuk sa un yŏ chi sujak" 五月七日余在寶恩山房 藏公携酒相過厚意也 拈周易坎六四韻 與之酬酢, Tasan simunjip, vol.5. 52 Chaegǒ 齋居 : refers to the king's retreat to a quiet place to deliberate the final verdict of a criminal case.

53 "Ku'u ch'a gyu sang ku'un" 久雨次睽上九韻, Tasan simunjip, vol. 5.

Hyejang as being a Sŏn monk and versed Confucian at the same time. 55 This idea is found again later when Tasan refers to the monk Ch'oŭi. 56 Moreover, in his late writings, Tasan seems to describe himself in the same way.

Tasan sometimes expresses a close attachment to the Buddhist way of life, drawing parallels between it and Confucianism in a somewhat syncretistic manner. A good illustration of this is to be found in a letter he wrote to his elder brother Yakchŏn in 1812:

In Buddhism, you have the "method by studying" and the "method by meditation."

Monks who adopt the "method by studying" therefore practice meditation in their later years. This is also what I wish. However, the hardships of the "method by meditation" demand much more effort than studying the Classics. I just hope my determination is unwavering. Zhu Xi was a master of the "method by studying," Lu Xiangshan a master of the "method by meditation." Categorically, a master of the "method by studying" is close to Yu, Ji, and Mozi; a master of the "method by meditation" to Yan hui and Yangzhu. 57 Tasan also socialized with other monks, 58 and at their request made a major contribution to Buddhist historiography by compiling the Gazetteer of Mandŏk 55 "Aam Changgong t'ammyŏng" 兒庵藏公塔銘, Tasan simunjip, vol. 17. 56 Hong Chikp'il 洪直弼 (1776-1852), a great Confucian scholar from the Yŏngnam region, seems to have used a similar expression (爲儒爲禪) when referring to the monk In-ak 仁岳 (?-1796), who was also known to have been versed in Confucian Classics since his youth. Cf. Chŏng Pyŏngjo and Yi Sŏkho, Han'guk chonggyo sasangsa, Pulgyo Togyo p'yŏn (Seoul: Yŏnse taehakkyo ch'ulp'anbu, 1991), 172-173.

57 "Tap Chungssi" 答仲氏, Tasan simunjip, vol.20. 58 Chŏng Min, "Tasan kwa Ŭnbong ǔi kyoyu wa Man'il amji," Munhŏn kwa haesŏk 44 (2008), 11-27 monastery 萬德寺志 and the Gazetteer of Taedun monastery 大芚寺志. 59 These texts constitute important accomplishments and are a legacy of the history of Buddhism in Korea. What is noteworthy here is that Tasan considered Korean Buddhist history and culture as being part of a more extended identity of his country. 60

Social Interaction with Buddhists

After Hyejang passed away, Tasan continued his exchanges with monks from Mandŏk monastery 61 and Taedun monastery. 62 He had particular affection for Wanho Yun'u 玩 虎尹佑 (1756-1826) from Taedun monastery, who was Yŏndam Yuil's disciple, and Ch'oŭi Ŭisun 草衣意洵 (1786-1866) and Hoŭi Sio 縞衣始悟 (1778-1868) 63 , who were Wanho's disciples. Ch'oŭi studied the Book of Odes and the Book of Changes with 59 Chŏng Min, "Han'guk kyohoesa yŏn'guso sojang Tasan ch'inp'il sŏganjip." Ch'oe Pyŏnghŏn ("Tasan Chŏng Yagyong ǔi Han'guk Pulgyosa yŏn'gu,"333-341) discussed the meaning and the limits of Tasan's achievements in this. 60 O Kyŏnghu, "Chosŏn hugi pulgyosa ch'ansul kwa 'Taedong sŏn'gyo ko'," Han'guk sasang kwa munhwa 35 (2006), 86-87 and 95. According to him, Tasan's historiographical compilation about Korean Buddhism was in line with that of his contemporaries, especially those belonging to the socalled schools of "pratical studies", in their understanding of their own history and cultural tradition.

He also acknowledged that through his working methods such as the collection of material and critical and philological research for the comipilation of monographies on monasteries, Tasan exerted an intellectual influence on the monks who collaborated with him.

61 Also known as Paengnyŏng sa 白蓮寺.

62 Also known as Taehǔng sa 大興寺.

63 Chŏng Min, "Han'guk kyohoesa yŏn'guso sojang Tasan ch'inp'il sŏganjip;" O Kyŏnghu, "Chosŏn hugi Taedun saji ǔi p'yŏnch 'an," 351-355. Tasan; after returning home following his exoneration, Tasan suggested that he settle close to his hometown. 64 The letters that Tasan sent to Ch'oŭi between 1813 and 1814 can be found in the literary collection of Sin Hǒn rather than in Tasan's own collected works. 65 The most remarkable thing about these letters is their use of Buddhist wording and the forcefulness of their language, sounding like the exchanges between master and disciple. Desiring to show him the right path by comparing Buddhism and Confucianism, Tasan insists at times on the similarities between the two teachings, and at other times on their differences. 66 Hoŭi's secular surname was Chŏng 丁, just like that of Tasan. The letters Tasan sent Hoŭi between 1813 and 1815 can be found in the Maeok sŏgwe 梅屋書 匭 , a collection of Tasan's letters. 67 Tasan also instructed him, and encouraged him to continue learning. Even after Tasan's return home, Hoŭi continued the relationship with Tasan's family. In 1817, Tasan also compiled a collection of poems with other young monks. 68 In 1818, having returned home upon his exoneration, Tasan founded the "Tasin 64 Chŏng Min, "Saero ch'ajǔn Tasan ǔi san'gŏ chabyŏng 24 su," Munhŏn kwa haesŏk 42 (2008), 194. 65 This is Sin Hŏn's 申櫶 Kǔmdang kiju 琴堂記珠. See Chŏng Min 정민, "Ch'oǔi ege chun Tasan ǔi tangbu," Munhŏn kwa haesŏk 41 (2007): 49-69. 66 Chŏng Min, "Ch'oǔi ege chun Tasan ǔi tangbu," 63. 67 Chŏng Min, "Han'guk kyuhoesa yŏn'guso sojang Tasan ch'inp'il sŏganjip." 68 Chŏng Min, "Saero ch'ajǔn Tasan ǔi san'gŏ chabyŏng 24 su," 188. knowledge of the Buddhist way of life, he did not convert to Buddhism. Although he approved of Buddhist discipline, he kept himself at a distance, or at least wished to give such an impression. As we have already seen, he once needed to justify a poem he had composed by placing himself in the shoes of Hyejang. When he compiled a collection of letters exchanged with Hyejang, the Record of Looking at the Moon, he implored Hyejang to keep them to himself, and when he sent monks his gazetteers of monasteries, he firmly requested they be kept confidential for a period of time. 73 All of this implies a wariness of the rigid political and societal norms, which would disapprove of Tasan's ambiguous position vis-à-vis Buddhism. Ambiguity can emerge from a contradiction that inivtes to or even imposes a choice between two opposites established by the contradiction itself. In Tasan's case, the contradiction does not come from his understanding of Confucianism nor of Buddhism, but from the political and societal repression of his time. Incompatibility between two traditions was in public space, in social context, not in private place. Hence, we would be misguided if we tried to see his ambiguity as a supposed dichotomy between Confucianim and Buddhism.

After returning home following his exoneration in 1818, Tasan continued his excursions to monasteries, but now socialized more with his old or new Confucian scholarly friends and less with monks. The most distinctive feature of this period is the 73 Chŏng Min, "Tasan kwa Ŭnbong ǔi kyoyu wa Man'il amji." way Tasan compared his own situation with the monks' monastic life, and expressed his views through their world or his aspirations to belong to it:

Only in a dream is the King's meat stew bestowed unto me Only an old priest's dark red bowl is being shared now 74 [1824] Yearning afar for the lofty Buddhist monastic world, at this stage he explicitly acknowledges that there was a Way in Buddhism: "Study for Writing" and "Hermitage of the Bamboo Cane" neighboring each other On the very top, Zen practice rooms 74 "Han'am chasuk to" 寒菴煮菽圖, Tasan simunjip, vol.6. 75 The monastery Tasan had visited as a youth.

76 "P'algwaebong sije Cho chŏng-ŏn sanjŏng aek" 八卦峯詩題趙正言山亭額, Tasan simunjip, vol. 6. In these poetical writings, and in contrast to the previous ones from his period of exile, he provides no additional explanations: Tasan was thus more expressive of his open affinity for the Buddhist world. With old age and the lack of possibility for any new appointments in government, he may have felt he no longer needed to justify himself. Furthermore, he openly asserted that if he could not spend the rest of his life in a monastery, then it would not be because of his own refusal, but due rather to societal restraints:

81 "Ku'u sangga ch'a'un tongp'a kuhan sim'u chi chak samsu pongsi song'ong, sam" 久雨傷稼 次韻東坡久旱甚雨之作三首 奉示淞翁, 三, Tasan simunjip, vol. 6.

82 "Kyŏng'in chesŏk tong cheu pun'un, che o, chǔng ch'oǔi sŏn" 庚寅除夕同諸友分韻, 其五, 贈草衣禪, Tasan simunjip, vol. 6.

Confucianism and Buddhism are based firmly in a quest for truth and asceticism. The second type is closeness in group organization. Both traditions are "lenient" about membership. This is generally the case of Confucianism, in which there is no priestly caste. And it is also the case of lay groups in Buddhism. 84 The third type is historical closeness. These two traditions had coexisted on the Korean peninsula for more than a millennium. For this reason, they can be understood together as an extended cultural identity. These three first types of closeness characterize the relationship between Confucianism and Buddhism in Korean (and also East Asian) history in general. These forms of closeness, confirmed in private spheres, facilitated profound mutual understanding through empathy and direct experiences. This mutual understanding led to a degree of tolerance in a large and active sense, and to the acceptance of the simultaneous existence of two different cultures. The following fourth and fifth forms of closeness are rather specific to some individual cases, such as that of Tasan. The fourth form of closeness is closeness in space. The Buddhist world, in the form of monasteries and monks, was always physically close to Tasan: in his hometown, in Seoul where he attended the Sunggyungwan and had an official career, in his regional wanderings, in exile. In other words, almost everywhere he went. The fifth and last form is closeness in 84 Yee-Heum Yoon [Yun Ihŭm], "The Contemporary Religious Situations in Korea," in Religion and Society in Contemporary Korea, ed. by L.R. Lancaster & R.K. Payne (Berkeley: IEAS University of California, 1997), 9-10. He uses the term "soft" to describe attitudes towards membership a particular social situation. Tasan's eighteen-year exile was decisive in his relationship with the Buddhist world. It put him in a marginal and restricted situation similar to that of Buddhist monks, who were also alienated but shared similar cultural tastes with Tasan. Through these different forms of closeness, as well as personal connections, mutual pragmatic interests, favorable impressions, empathetic experiences, the adoption of lifestyles, the understanding of common ultimate objectives and so on, contact was spontaneously established and the two worlds drew closer together.

Personal Encounter

In the case of Tasan, it was neither the internal logic of the Confucian tradition nor its differences with Buddhism, but rather external factors, namely political principles and social discrimination, which made exchanges and coexistence with the Buddhist world so problematic. In a public sphere dominated by political concerns, the previouslymentioned closeness could be concealed. Such closeness was intentionally disregarded or treated as something very perilous, because Buddhism, though it shared traits with Confucianism, was "heterodox." Along with dominant prejudices, discourses and typifications, political ideology and social discrimination regulated the coexistence and exchanges between the two traditions and maintained a distance and a boundary between them. This is where Chŏng Ch'angsu's explanation left off. But this was just one side of the coin.

A personal encounter, especially face-to-face interaction and repeated direct experiences, provides an opportunity to overcome these obstacles to interaction. In a face-to-face situation, mutual interference can occur that affects each person's subjective impressions and interpretation. This can make established typifications more vulnerable and, as a result, modify the distances or barriers between the two traditions thus separated. By virtue of face-to-face encounters, a real social relationship can be modified or newly formed. 85 This is also one of the reasons why we cannot overlook the study of the personal dimension in social and cultural history.

Conclusion

We have seen that Tasan's attitudes and trajectory with regard to the Buddhist world reveal not only his own personal history, but also the system of meaning of his society.

His behavior was understandable for many of his contemporaries, who themselves often behaved in a similar manner. Thus, his attitudes undoubtedly had a significant place in 85 For a more detailed account of the relationship between the formation of knowledge and face-to-face encounters, see Peter Berger & Thomas Luckmann, "The Foundations of Knowledge in Everyday Life," in The Social Construction of Reality (Anchor Books, 1967), 19-46. political identity, in just the same way that "a rose by any other name would smell as sweet," the encounter between the two worlds would have been admitted and been viewed as highly relevant. In eighteenth-century Korea, when Confucian socio-political coercive forces were weakened, numerous other cases of Confucian-Buddhist personal interaction, like those of Tasan, can also be found.

There were probably more diverse, individual factors leading learned men to the Buddhist world one way or another, resulting in interaction or a kind of religious conversion. Tasan's case may belong to the former, a kind of interaction amounting to cultural "consumption" without "conversion." The latter, a kind of conversion, could have been the result of euphoria or a feeling of being blessed, as in the case of King Chŏngjo (1752-1800) who, after the birth of a prince, acknowledged his devotion to Buddha; or due to a disillusionment with the Confucian world and the contrasting solace found in Buddhism, as in the cases of Kim Ch'anghǔp (1653-1722) and the profound grief provoked by his father's death on royal command, or Ch'oe Ch'angdae (1669-1720) after having gone through political hardship. There must be other cases, as well.

In the future, it would be relevant to examine in greater detail how widespread these types of individual experiences were and what other forms of social and cultural interaction and dynamism took place during the late Chosǒn period, in order to better

  exchanges, or have expressed doctrinal viewpoints. The topics covered have mainly been concepts or literary writings. Any relationship going beyond ideological and 6 Many works can be referred to as models in this respect. The most outstanding work in this context, in my opinion, must be the Fêtes et chansons anciennes de la Chine by Marcel Granet, one of the most famous French sinologists, from whom Claude Lévi-Strauss obtained many inspirations for his monumental works. Granet analyzed the poems from the Shijing 詩經 to explain the society of ancient China. The arts are one of the legitimate objects of scientific research in from cultural history to sociology, from the Autumn of the Middle Ages by Johan Huizinga, who is concerned with the style of a whole culture through individual paintings and poems, to Sociology of the Arts: Exploring Fine and Popular Forms by Victoria Alexander who is interested also in rock music. 7 One of the most representative and recently released works on the relationship between Confucian intellectuals and Buddhism in the Late Chosŏn period is Yu Hosŏn, Chosŏn hugi Kyŏnghwa sajok ŭi pulgyo insik kwa pulgyo munhwa (Seoul: T'aehaksa, 2006). It deals with scholars of the first half of the eighteenth century, such as Kim Ch'anghŭp, Ch'oe Ch'angdae, Yi Ŏksu, Yi Hagon, and Cho Gwimyŏng, as well as their thought and literature.

  19 19 For example, Chŏng Chaegŏl, "Chosŏn sidae ponggŏn sahoe ŭi kyoyuk kujo," Han'guk kyoyuk 15 (1988): 5-19.

  Culture,Ideology and Politics, ed. by R.Samuel & G.S. Jones (London: Routledge & Kegan Paul Ltd., 1982), 2-11. There he defines it as "the force of inertia of mental structures" (8).21 There are some works about the interaction between Buddhism and Confucianism (and Taoism) in the history of China. Among them, Paul Demiéville's "La pénétration du bouddhisme dans la tradition philosophique chinoise" (in Choix d'études bouddhiques [Leiden: E.J. Brill, 1973], 1-38) provides a concise and interesting historical overview. Tasan also showed Ch'o-ŭi parallels between some Confucian and Buddhist terms. See Chŏng Min, "Ch'oǔi ege chun Tasan ǔi tangbu," Munhŏn kwa haesŏk41 (2007), 49-69.

(

  penname Tasan), a representative Confucian scholar between the second half of the eighteenth century and the first half of the nineteenth century. Tasan was a committed Confucian and never abandoned the life and spirit this implied. But he was also 25 I have shown some similar cases from commentaries on the Laozi by Confucian literati: Kim Daeyeol, "Chosŏn Confucian scholars' attitudes toward the Laozi," Sungkyun Journal of East Asian Studies 7, no. 2 (2007), 17-22.

  30 "Choch'u pae chungssi yu pong-ŭnsa" 早秋陪仲氏遊奉恩寺, Tasan simunjip, vol.1. 21 hometown. In a poem composed at the time, he describes the joyful welcome of his monk acquaintances and expresses his satisfaction with the monastery: Hermits also love the indigo color of the chinsa [dress],Not having banished worldly thoughts altogether.31 During this same spring, he returned to his hometown and once again visited Sujong monastery. Three days later, he composed the following poem:No desire to ever go back to the storms of life Just one more serene night here! 32A Personal Relationship with the Buddhist WorldTasan also displayed in several writings his knowledge about the history of Korean Buddhism, especially about monks of great virtue. Between 1777 and 1779, during his stay in the town of Hwasun, 33 his father's place of work, he visited such monasteries as Manyŏn 萬淵寺, where he composed a "Panegyric over the portrait of National Master Pojo." 34 Moreover, Tasan had numerous personal contacts with Buddhist monks. The earliest traces of his friendship with monks can be found in his poem written to monk 31 "Suk pongŭn-sa" 宿奉恩寺, Tasan simunjip, vol.1.

(

  Chŏngjo) […] As for monks, they are undoubtedly first-rate heretics, but they should be treated appropriately considering their desperate ascetic devotion and discipline unattainable by ordinary laymen and their aspiration to goodness identical to ours […]. (Tasan) […] As for monks and nuns, they have been notorious since olden times for exploiting innocent people using talismans and chanting invocations, and a good deal of deceitful figures have not infrequently emerged from amongst them to harm virtue and destroy decent tradition. […] Once the government starts to approve and praise them, it may propel innocent people into their snares. While Your Highness rightly dispels them, so as to open the eyes of unenlightened people, I sincerely regret and feel grief about your words [as above].

…

  Whoever allowed only a few monks to dwell in this ethereal pristine hill and valley … My uncontrollable desire to reside here Is not merely to have fun and fool around46

…

  What a decisive and trustworthy person is this sincere and nice Porija 甫里子! Staying up many nights talking with him assured me of his open-heartedness and warm-heartedness Oh ! those disgusting, tenacious souls, their lips teeming with jealousy With all these forty long years of life breathing in this dusty world, I never thought that a true and genuine friend would be here right by the southern seaside. Let us open our hearts no difference between old or new friends In this vast and deep Yongmun valley quite suitable for retirement, Let us live together as hermit neighbors to old age until death 48 During this time Tasan visited monasteries more often than before, stayed with the 48 "Chŭng Porija" 贈甫里子, Tasan simunjip, vol.4.

…

  At dawn, a reddish rising sun peeking through the small window in the wall Tame deer and squirrels running through the door A cat brought over and stroked on the forehead With merciful Buddha's mind as on a grandchild's forehead … With a necklace taken off, sitting absentmindedly Waiting until the incense before Buddha is burnt into ashes 29 Moreover holding a volume of biographies of renowned monks Napping over half a day in the shade of a table Chanted sutras through the bamboo garden becoming more soothing to the ears as one gets older Yet, the vicissitudes of life's waves are hindrance as well With a pine-leaf hat on, sipping soup made of pine leaves I'd rather delve into Buddha's teachings in my remaining years in this world 49

Behold

  Sujong monastery 75 far away on the very edge of the sky With its Zen tower standing aloof from the world Resounding in the wind is the reciting of a sūtra Undoubtedly by a soul enlightened by the Way 76 [1824 spring] The way he expresses his regrets for not having reached the stage of self-cultivation he had previously aspired to is obviously influenced by Buddhism, and shows to what extent the Confucian and Buddhist world had become intertwined in his mind. … With all the longing for wife and children so utterly shed off Shall I read the classics of sages on snowy days 77 [14 th day of ninth month, 1820]

  77 "Yongmun sa" 龍門寺, in 'Kyŏng'ŭi si' 經義詩, Tasan simunjip, vol. 7. 40 Life scarcely has room for taking a stroll in the mountains Failed in keeping the karma of offering service for the Buddha's birthday 78 [spring 1827] … How ridiculous it is that the poor learned scholar toiled in vain Achieving merely a self-styled Zen philosophy … As I learned of equality in attaining Buddhahood Good books fully packed in the stacks are not pulled out to read any more 79 [1827] To imagine abandoning one's family is certainly not an appropriate attitude for a serious Confucian. Indeed, it was one of the aspects of Buddhism that Confucians criticized most. Poems composed by Tasan during this period display an intermixing of Confucian and Buddhist ethos, and Buddhist wording is frequently employed: … Utter emaciation from harsh discipline of avoiding cereals learnt from master monk Sprinkled water denoting the real attainment of Buddha contemplating water 水觀佛 […] 80 [sixth month, 1828] Not going out since legs became paralyzed 78 "U Hyŏn-gye chabyŏng sipchŏl" 又玄溪雜詠十絶, Tasan simunjip, vol. 6. 79 "Ch'aun Pŏm Sŏkho Pyŏng-o sŏhoe sipsu kan-gi Song-ong" 次韻范石湖丙午書懷十首簡寄淞翁, Tasan simunjip, volume 6. 80 "Ku'u sangga ch'a'un tongp'a kuhan sim'u chi chak samsu pongsi song'ong" 久雨傷稼 All kinds of ailments coming and going, and the paralysis is unrelenting Confined in this chief monk dwelling quarters, sleeping, awaking, loafing and resting, Meditation "facing the wall" 面壁 must rather be like meditation "contemplating the heart-mind" 觀心! […] 81 [sixth month, 1828] Drooped grass garments Bald head with unkempt hair strewn over Stripped off monk skin Confucian bony core exposed Old mirror already ground and burnished New axes not blunt Enlightened clearly by nowThis is just the "second moon"82 [twelfth month, 1830]

See for example, Cho Sŏngŭl's Yŏyudang chip ŭi munhŏnhakchŏk yŏn'gu(Seoul: Hyean, 2004).

For an early representative study see Yi Chongch'an, Han'guk pulga simunhaksa non (Seoul: Pulgwang ch'ulp'anbu, 1993).

Kim Sŏngǔn, "Chosŏn hugi sŏnbulgyo chŏch'esŏng ǔi hyŏngsŏng e taehan yŏn'gu" (PhD diss., Seoul National University, 2012), 47.

Yi T'aejin, "Chosŏn wangjo ǔi yugyo chŏngch'i wa wanggwŏn," Hanguk saron23 (1990), 231.

Chŏng Ch'angsu, "Chosŏnjo ŭi munhwa hyŏnsang ŭi ilch'ŭngmyŏn e kwanhan kinŭng chuŭi chŏk punsŏk," Sahoe kwahak 27:1 (1987), 7-28.

Nam Hǔisuk, "16-17 segi pulgyo ǔisikchip ǔi kanhaeng kwa pulgyo taejunghwa," Han'guk munhwa34 (2004), 97-165.

Michel de Certeau, L'invention du quotidien, 1. arts de faire (Paris: Editions Gallimard, 1990), xxxvi-xl.

Jonathan Smith, "Religion, Religions, Religious," in Critical Terms for Religious Studies (University of Chicago Press, 1998).

In my current research, I have studied approximately eighty authors who lived during the eighteenth century (identified in the Munjip ch'onggan). Among these, about sixty left writings that are in some way or other related to the Buddhist world.

In Sŏsan-si, South Ch'ungch'ŏng province.

Present-day Sinch'ang-ni, Unsan-myŏn, Sŏsan-si.

"T'aean kunsu Yu Hŏn'ga (hoe) kyŏnbang tongji Kaesimsa Tongdae chomang ilsuk i pyŏl" 泰安郡守柳獻可誨見訪同至開心寺東臺眺望一宿而別, Tasan simunjip, vol.1.

"San-gŏ chaphŭng" 山居雜興, Tasan simunjip, vol.5.

Ibid.

of monk acquaintances and their visits to his home. In his "Miscellaneous Poems from the Tower of Breeze in the Pine Trees," written circa 1810, Tasan confesses that his lofty style of living resembles that of monks. I am learning the monastic ways of life one by one 54 The expression "to espouse the joy of the Buddhist doctrines" appears in the Vimalakirti Sūtra 維摩經. The quotes above may also partially indicate Tasan's approval of Buddhist values, as he learned the monastic life of monks and accommodated Buddhist culture into his own without actually converting.

In 1811, Aam Hyejang passed away. In the ninth month of the same year, Tasan wrote a funeral address for him. In an epitaph for Hyejang's pagoda that he wrote during the same period, Tasan gave a detailed description of the circumstances in which he had met Aam Hyejang for the first time. In this text, he remembered that he had recognized 54 "Songp'ungnu chapsi" 松風樓雜詩, Tasan simunjip, vol. 5.

Mutual Aid Society" (Tasin kye 茶信契) comprised of his disciples from the Kangjin area and two disciples of Hyejang, Suryong and Chyegyŏng. The society's aim was to continue the scholastic relationship of its members and provide mutual aid. Tasan specifically implored those disciples in the club who were not monks to help the two monks in their difficult times. In the society's charter, we can read the following clause:

Suryong and Chegyŏng entered into our study relationship from the outside. When there are worries or difficulties in the farmland of the "Chŏndŭng Mutual Aid Society," the town office has to be informed so that arrangements and care may be provided. 69 The "Chŏndŭng Mutual Aid Society" mentioned here seems to have been organized in a similar way as the Tasin Society, i.e., by monks who shared a scholastic relationship with Tasan. 70 This is one example of Confucian intellectuals accommodating Buddhist monks into their social structure, a significant event, from our viewpoint, in Confucian-Buddhist interaction.

The second case of his social mixing is with another monk who later on, in 1830, took part in a literary club of Confucian intellectuals associated with Tasan. The Sŏn monk Ch'oŭi, whom Tasan had met during his Kangjin exile, joined the Turŭng Society of Poets [also known as the Yŏlsang Society of Poets], a well-attended poetry club in 69 Yi Ŭlho, "Chŏnnam Kangjin e namgin Tasin gyejŏlmok ko," Honam munhwa yŏn'gu 1 (1963), 34-36. 70 Im Hyŏngt'aek, Silsa kusi ǔi han'gukhak (Seoul: Ch'angjak kwa pip 'yŏng sa, 2000), 416-417. the Yangsuri area, Tasan's home region. 71 In a lonely house with a gate of worn-out whitish bamboo twigs at the foot of a mountain Sour rice wine and brewed milk keep friends up late All the poets in attendance say a welcome to a monk Seeing him face to face, he is none other than Ch'oŭi from the south 72 [twelfth month, 1830] Truth Found in Buddhism, and Personal Aspirations over Socio-political Constraints Until the end of his exile period, Tasan seems to have ever been conscious of the fact that the eyes of the government and other Confucians were upon him. In some of the previously-quoted texts, we find certain examples of Tasan's conflicting attitudes. On the one hand, as a learned Confucian, he appreciated the Buddhist world for its atmosphere, which was much better for self-cultivation. Considering the fact that the central government had dismissed him, and that local government was teeming with corruption and unlawfulness, Tasan could not help but abhor officialdom when he compared them to the pure and serene way of life of Buddhist monks, of whom he grew increasingly envious. On the other hand, however open-minded he was, Tasan remained faithful to Confucianism. Despite his friendly relationships with monks and his 71 Kim Yŏngjin, "Yusan Chŏng Hagyŏng ŭi saengae wa chŏjak e kwanhan ilgo," Tasanhak 12 (2008), 82.

72 "Kyŏngin chesŏk tongjeu punun, ki ch'il" 庚寅除夕同諸友分韻其七, Tasan simunjip, volume 6. Here, the term "closeness" means both "proximity" and "similarity." In Tasan's case, as far as we know, no philosophical or doctrinal arguments, or religious convictions, seem to have played a central role in the interaction between these two worlds. The first type of closeness which needs to be mentioned is closeness in spirituality. Both Neo-83 "Hyŏn-gok chapyŏng hwa Yŏ sŭngji" 玄谷雜詠和呂承旨, Tasan simunjip, vol. 6.

Chosŏn culture. 86 During this period, despite there being numerous forms of contact with the Buddhist world open to Confucian intellectuals, social constraint, dogmatic coercion, and supervision by the regime hindered their deeper interaction with it. For Confucian intellectuals, inasmuch as they were occupied with and restrained by their own social status, close as the Buddhist world was, it was kept at a distance. Their knowledge about it thus remained rigidly patterned, and for most of them, fixed ideas and a sketchy understanding regarding Buddhism contributed to their keeping it at a distance. On the other hand, for those free from ideological shackles or living in provincial society where political and social control was looser, or for curious, open-minded or disillusioned Confucians, the role of the Buddhist world seems to have been very significant indeed.

For such individuals, the Buddhist world was probably as close as, or even closer than, the Confucian world. This is what Tasan experienced during his exile in Kangjin. Also, through his personal trajectory, one can see how it became possible for Buddhist monks to participate in social organizations with Confucian literati. Needless to say, Confucian and Buddhist traditions had numerous things in common, such as philosophical questioning, contemplation, modes of expression and practice, as well as other cultural elements. Therefore, had higher values been based on universal principles rather than on 86 See above, note 12.

understand the degree to which the Buddhist world was close to, and a constant environment for, Confucian literati, and how Buddhist culture was shared between different social classes during this period of Korean history.


Dalia El Badawy
email: dalia.elbadawy@technicolor.com

Alexey Ozerov
email: alexey.ozerov@technicolor.com

Ngoc Q K Duong

RELATIVE GROUP SPARSITY FOR NON-NEGATIVE MATRIX FACTORIZATION WITH APPLICATION TO ON-THE-FLY AUDIO SOURCE SEPARATION

Keywords: group sparsity, non-negative matrix factorization, audio source separation, universal model

We consider dictionary-based signal decompositions with group sparsity, a variant of structured sparsity. We point out that the group sparsity-inducing constraint alone may not be sufficient in some cases when we know that some bigger groups or so-called supergroups cannot vanish completely. To deal with this problem we introduce the notion of relative group sparsity preventing the supergroups from vanishing. In this paper we formulate practical criteria and algorithms for relative group sparsity as applied to non-negative matrix factorization and investigate its potential benefit within the on-the-fly audio source separation framework we recently introduced. Experimental evaluation shows that the proposed relative group sparsity leads to performance improvement over group sparsity in both supervised and semi-supervised on-the-fly audio source separation settings.

INTRODUCTION

Dictionary-based signal decompositions usually benefit from sparsity or structured sparsity constraints, especially in the case of overcomplete dictionaries. Group sparsity is a variant of structured sparsity that became quite popular in both signal processing [START_REF] Hurmalainen | Group sparsity for speaker identity discrimination in factorisation-based speech recognition[END_REF] and machine learning [START_REF] Bach | Optimization with sparsity-inducing penalties[END_REF]. In particular, several approaches using group sparsity for audio source separation were recently proposed [START_REF] Lefèvre | Itakura-Saito nonnegative matrix factorization with group sparsity[END_REF][START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF]. While the idea behind sparsity is to allow only few coefficients of the decomposition to be active (i.e., having non-negligible energy), the idea behind group sparsity is to allow only few pre-defined groups of coefficients to be active. These groups of coefficients are usually defined relying on some prior knowledge about the signal and on some desired properties of the decomposition. For example, in the context of speaker independent single channel speech denoising problem Sun and Mysore [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF] propose modeling speech from an unknown speaker by a union of few dictionaries from a large amount of pre-trained speaker-dependent groups of dictionary patterns. Signal decomposition within this dictionary also called universal speech model is achieved via group sparsity, where one group consists of all coefficients within the decomposition that correspond to one pretrained dictionary. However, the group sparsity constraint alone may not be sufficient in some cases. Let us explain this by one example. Consider the problem of single channel separation of two speech sources: one male speech source and one female speech source. In line with [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF], let us assume that the two sources are modeled by a universal male speech model and a universal female speech model, respectively. A straightforward application of a group sparsity-based approach as in [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF] would assume that the mixture of sources is decomposed in the union of several male and female pre-trained dictionaries. In that case it can happen, especially if the female source voice is close to a male's one, that all the active groups (the selected dictionaries) will belong to the universal male speech model. As a consequence, the full mixture will be appointed to only one source. Although, we know that there are two sources. To avoid this problem one solution would consist in explicitly preventing the coefficients corresponding to one universal source model from vanishing altogether.

Formulating such a solution in a more general manner, we introduce in this paper the notion of relative group sparsity. We assume that the groups are assembled into so-called supergroups (i.e., bigger groups corresponding to the universal speech models in the above example) and we characterize a relative group sparsity constraint as

• inducing the sparsity of the groups (as in the group sparsity), while

• inducing the "anti-sparsity" of the supergroups (i.e., preventing them from vanishing entirely).

In other words, the group sparsity property is now considered relative to the corresponding supergroup and not within the full set of coefficients.

In this paper we formulate practical criteria and algorithms for relative group sparsity as applied to non-negative matrix factorization (NMF) with Itakura-Saito (IS) divergence [START_REF] Févotte | Non-negative matrix factorization with the Itakura-Saito divergence. With application to music analysis[END_REF] and investigate its potential benefit within the on-the-fly audio source separation framework [START_REF] Badawy | On-the-fly audio source separation[END_REF] we recently introduced. While other user-guided source separation approaches require from the user certain skills and/or knowledge (e.g., humming or speaking source examples [START_REF] Smaragdis | Separation by humming: User-guided sound extraction from monophonic mixtures[END_REF][START_REF] Magoarou | Textinformed audio source separation using nonnegative matrix partial co-factorization[END_REF]; or annotating the mixture spectrograms [START_REF] Lefèvre | Semi-supervised NMF with time-frequency annotations for single-channel source separation[END_REF][START_REF] Bryan | Interactive refinement of supervised and semi-supervised sound source separation estimates[END_REF][START_REF] Duong | An interactive audio source separation framework based on nonnegative matrix factorization[END_REF][START_REF] Duong | Temporal annotation-based audio source separation using weighted nonnegative matrix factorization[END_REF]), this framework allows in principle separating mixtures of any sounds with very light guidance that can be performed by almost any user. Briefly, after having listened to the mixture a user is only required to describe the sources to be separated by some keywords (e.g., "dog barking", "wind", etc.), and some external search engines are then used to retrieve the corresponding source examples for training. In line with the on-the-fly image retrieval approach [START_REF] Chatfield | Visor: Towards on-the-fly large-scale object category retrieval[END_REF], the source models are then learned on-the-fly and used for separation. A demo video of the the on-the-fly audio source separation user interface we have created is available at http://youtu.be/mBmJW7cy710/. We have found in [START_REF] Badawy | On-the-fly audio source separation[END_REF] that among other methods we tested those based on the universal modeling concept with group sparsity [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF] performed the best. However, since these methods are based on several universal models, as in the male/female speech separation example above, they may suffer from exactly the same problem of source vanishing and we expect the proposed relative group sparsity to fix it.

In summary, the main contribution of this paper consists in introducing the notion of relative group sparsity and formulating corresponding practical criteria and algorithms for the NMF model. The potential of this new sparsity is demonstrated within the on-the-fly audio source separation framework. In addition, we investigate the on-the-fly audio source separation in the semi-supervised case, i.e., when retrieved source examples are only available for some but not all sources. We show how relative group sparsity is crucial in that case as well.

The remainder of the paper is organized as follows. Section 2 summarizes the on-the-fly audio source separation framework based on NMF with group sparsity as introduced in [START_REF] Badawy | On-the-fly audio source separation[END_REF]. Section 3 briefly overviews the modifications we propose within this framework to efficiently handle the semi-supervised case. In section 4 the proposed criteria and algorithms for NMF with relative group sparsity are described. Numerical results are given in section 5 followed by the conclusion in section 6.

SUPERVISED ON-THE-FLY AUDIO SOURCE SEPARATION BASED ON NMF WITH GROUP SPARSITY

This section summarizes the on-the-fly audio source separation framework based on the NMF with group sparsity [START_REF] Badawy | On-the-fly audio source separation[END_REF].

Supervised NMF-based source separation

We consider a single-channel source separation problem with J sources. Let X and Sj be the F × N matrices of the short-time Fourier transform (STFT) coefficients of the observed mixture signal and the j-th source signal, respectively, where F is the number of frequency bins and N the number of time frames. The mixing model writes

X = J j=1 Sj. (1)
Let V = |X| .2 be the power spectrogram of the mixture where A .p is the matrix with entries [A] p ij . NMF aims at decomposing the F × N non-negative matrix V as a product of two non-negative matrices W and H of dimensions F × K and K × N , respectively, such that V ≈ V = WH. In audio applications this decomposition is often done by optimizing the following criterion [START_REF] Févotte | Non-negative matrix factorization with the Itakura-Saito divergence. With application to music analysis[END_REF] min

H≥0,W≥0 D(V WH), (2)
where

D(V V) = F,N f,n=1 dIS(V f n Vfn ) and dIS(x y) = x y - log( x y ) -1 is the IS divergence [5]
. The parameters θ = {W, H} are initialized with random non-negative values and are iteratively updated via multiplicative update (MU) rules [START_REF] Févotte | Non-negative matrix factorization with the Itakura-Saito divergence. With application to music analysis[END_REF].

In the supervised setting, the factorization of V is guided by a pre-learned spectral model. In other words, the matrix W is obtained (and fixed within the optimization) by

W = [W (1) , . . . , W (J) ], (3)
where W (j) is the spectral model for the j-th source learned via the NMF decomposition of some training examples using (2).

On-the-fly NMF-based source separation

The above supervised strategy could be also applied in the onthe-fly context by training the NMF spectral models (dictionaries) W (j) from the retrieved examples. However, this straightforward approach does not address the following two challenges:

H (1,1)
Group sparsity Relative group sparsity

(a) (c) (e) (b) (d) (f) H (1,2) H (2,1)
H (2,2)
H

H

H (1,1) 1. How to deal with irrelevant retrieved examples (i.e., sounds not corresponding to the sources of interest)? 2. How to deal with noisy retrieved examples (i.e., mixtures of relevant and irrelevant sounds)? To deal with these challenges, it was proposed in [START_REF] Badawy | On-the-fly audio source separation[END_REF] to rely on a universal model-based approach with group sparsity [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF]. This approach relies mainly on the following steps:

H (1,2) H (1,3) H b
1. Assume Lj examples were retrieved for the j-th source. For the l-th example (l = 1, . . . , Lj) a spectral model W (j,l) is learned optimizing (2). 2. The mixture spectral model W is constructed as in [START_REF] Lefèvre | Itakura-Saito nonnegative matrix factorization with group sparsity[END_REF], where each W (j) is a universal spectral model obtained by concatenation of the pre-trained example spectral models as W (j) = [W (j,1) , . . . , W (j,L j ) ]. 3. The non-negative activation matrix H is randomly initialized and estimated (while keeping W fixed) using the following criterion min

H≥0 D(V WH) + Ψ(H), (4)
where

Ψ(H) = J j=1 λj G j g=1 log + H (j,g) 1 (5)
is a group sparsity-inducing penalty defined as in [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF], • 1 denotes the 1 matrix norm, and λj are some constants, and H (j,g) (j = 1, . . . , Gj) are the groups within the activation sub-matrix H (j) corresponding to the j-th universal source model.

4. Sources are separated using standard Wiener filtering [START_REF] Badawy | On-the-fly audio source separation[END_REF].

An iterative algorithm optimizing criterion (4) based on MU rules [START_REF] Févotte | Algorithms for nonnegative matrix factorization with the beta-divergence[END_REF] is summarized by Algorithm 1, where η > 0 is a constant parameter, P (j,g) is a matrix with equal entries; its size is the same as H (j,g) , and P is a matrix concatenating all P (j,g) . This algorithm is almost identical to the one proposed in [START_REF] Lefèvre | Itakura-Saito nonnegative matrix factorization with group sparsity[END_REF], except that the groups are defined differently and W is not updated here. It is proven in [START_REF] Lefèvre | Itakura-Saito nonnegative matrix factorization with group sparsity[END_REF] using a majorization-minimization [START_REF] Hunter | A tutorial on MM algorithms[END_REF] formulation that these updates with η = 1/2 are monotonic, i.e., they ensure that the cost function in ( 4) is non-increasing after each iteration.

Algorithm 1 MU rules for NMF with group sparsity Input: V, W, λ Output: H Initialize H randomly V = WH repeat for j = 1, . . . , J, g = 1, . . . , Gj do P (j,g) ←

λ j + H (j,g) 1 end for H ← H W T (V V.-2 ) W T ( V.-1 )+P .η V ← WH until convergence
In our previous work [START_REF] Badawy | On-the-fly audio source separation[END_REF] we introduced two options for defining the groups H (j,g) . First, as in [START_REF] Sun | Universal speech models for speaker independent single channel source separation[END_REF], we restrict the groups to be sub-matrices of H (j) corresponding to the pre-trained example spectral models W (j,l) (in that case the indices g and l coincide and Gj = Lj). This so-called block sparsity-inducing strategy allows filtering out irrelevant spectral models W (j,l) , thus dealing with irrelevant retrieved examples (see, e.g., Fig. 1 (a) and (b)). Second, as an alternative solution, we restrict the groups to be lines of H (j) corresponding to different spectral components (in that case the number of groups Gj simply equals to the number of rows in H (j) ). This so-called component sparsity-inducing strategy allows filtering out irrelevant spectral components, thus dealing with noisy retrieved examples (see, e.g., Fig. 1 (c) and(d)).

While enforcing group sparsity as in ( 5) is useful for selecting the appropriate dictionary elements for the decomposition, it does not guarantee that elements from every learned source model are used; in other words, two or more sources in the mixture can be lumped together and expressed using the same dictionary elements making the separation impossible (as in the male/female speech example in the introduction). This "source vanishing" problem was observed in practice quite often and is illustrated in Fig. 1 (a) and(c). It can also be easily seen that increasing the constants λj in the penalty (5) (thus decreasing the number of active/emerging groups) increases the chances of source vanishing.

PROPOSED SEMI-SUPERVISED ON-THE-FLY AUDIO SOURCE SEPARATION

In this section we briefly describe a novel so-called semi-supervised on-the-fly audio source separation setup that was not addressed in [START_REF] Badawy | On-the-fly audio source separation[END_REF], but may be very useful in practice. In this setup we assume that for some of sources there are no retrieved examples available. That may happen either in the case when no keywords were provided for some of sources (e.g., because the user has not described all the sources either to save time or because he/she has not recognized some sources) or in the case when for some keywords no examples were retrieved by the search engine (e.g., if there are no sounds matching the corresponding queries). All these "undescribed" sources are modeled as one background source by a randomly initialized NMF model θ b = {W b , H b } with a small number of components (i.e., number of columns in W b ) K b . All the other sources, for which some examples are available, are modeled as in the supervised case by θ = {W, H} (see Fig. 1 (e) and (f)) and the parameters are estimated altogether by optimizing the following criterion min

H≥0,W b ≥0,H b ≥0 D(V WH + W b H b ) + Ψ(H). ( 6
)
We see that in contrast to criterion (4) W b is updated and there is no group sparsity-inducing penalty on H b . Criterion ( 6) may be optimized by MU rules that are very similar to those in Algorithm 1, and we omit them here for the sake of conciseness. Note that the source vanishing problem is even more problematic in this case than in the supervised case. Indeed, we have observed in many cases that the full matrix H vanishes, which means that the full mixture is modeled by the estimated background model θ b (see Fig. 1 (e)). This is very likely due to the fact that W b and H b are now fully unconstrained in ( 6), while W is fixed and H is constrained by the group sparsity-inducing penalty.

NMF WITH RELATIVE GROUP SPARSITY

According to the terminology described in the introduction we here consider H (j,g) as groups and H (j) , i.e., activation coefficients corresponding to universal models, as supergroups. In order to keep group sparsity, while assuring supergroups anti-sparsity, and thus hopefully fixing the problem of sources vanishing in the case of our application, we propose replacing the group sparsity-inducing penalty (5) by the following relative group sparsity-inducing penalty

Ψ rel (H) = J j=1 λj G j g=1 log + H (j,g) 1 H (j) γ j 1 , (7)
where γj are some non-negative constants. The new penalty ( 7) can be also rewritten as

Ψ rel (H) = Ψ(H) - J j=1 λjγjGj log H (j) 1 , (8)
and one can easily understand that, while the new penalty keeps the group sparsity property thanks to Ψ(H), it prevents the 1-norms of the supergroups from vanishing. Indeed, if H (j) 1 tends to zero, then -log H (j) 1 tends to +∞. Note also that this formulation generalizes the group sparsity approach, since (7) reduces to (5) for γj = 0.

To derive MU rules optimizing criterion (4) (or ( 6)) with a new penalty Ψ rel (H) we relied on MU rules derivation heuristics as described in [START_REF] Févotte | Algorithms for nonnegative matrix factorization with the beta-divergence[END_REF][START_REF] Lee | Algorithms for non-negative matrix factorization[END_REF]. The resulting MU rules for criterion (4) are summarized in Algorithm 2, where Q (j,g) is a matrix with equal entries; its size is the same as H (j,g) , and Q is a matrix concatenating all Q (j,g) (the same for P (j,g) and P, as above).

Algorithm 2 MU rules for NMF with relative group sparsity Input: V, W, λ Output: H Initialize H randomly V = WH repeat for j = 1, . . . , J, g = 1, . . . , Gj do P (j,g) ←

λ j + H (j,g) 1 Q (j,g) ← λ j G j γ j H (j) 1 end for H ← H W T (V V.-2 )+Q W T ( V.-1 )+P .η V ← WH until convergence
During our preliminary studies we also considered the following alternative version of penalty ( 7)

Ψ rel2 (H) = J j=1 λj G j g=1 log + H (j,g) 1 H (j) γ j 1 . (9)
The latter penalty cannot be nicely decoupled as penalty [START_REF] Smaragdis | Separation by humming: User-guided sound extraction from monophonic mixtures[END_REF] in [START_REF] Magoarou | Textinformed audio source separation using nonnegative matrix partial co-factorization[END_REF]. However, it has another potentially attractive property consisting in the fact that with γj = 1 it is fully invariant to the 1-norm of each supergroup H (j) . Since experimentally we have not found a big difference between penalty (7) and penalty [START_REF] Lefèvre | Semi-supervised NMF with time-frequency annotations for single-channel source separation[END_REF] in terms of source separation performance, and since MU updates for penalty (9) are more complex, we decided to use penalty [START_REF] Smaragdis | Separation by humming: User-guided sound extraction from monophonic mixtures[END_REF] in our experiments.

RESULTS

Note first that an informal analysis of activation matrices H has shown that the source vanishing problem does not happen any more for any value of λj and in both supervised and semi-supervised cases. This can be observed in the right column of Fig. 1.

Dataset and parameter setting

Our experimental setup, that we recall briefly below, is almost as in our previous work on on-the-fly audio source separation [START_REF] Badawy | On-the-fly audio source separation[END_REF], except that the number of mixtures is increased from 10 to 15, we here use two sound search engines instead of one in [START_REF] Badawy | On-the-fly audio source separation[END_REF], and some parameters are better tuned.

The test dataset we used consists of 15 single-channel mixtures of two sources artificially mixed at 0 dB SNR. The mixtures were sampled at either 16000 Hz or 11025 Hz and vary in duration between 1 and 13 seconds. The sources in the mixtures represent different types of sound ranging from human speech to musical instruments and animal sounds. In our experiments, the example wave files were retrieved from www.findsounds.com and www.freesound.org. The keywords used included guitar, drum, cat, dog, river, chirps, rooster, bells, and traffic.

For parameter settings, a frame length of 47 ms with 50% overlapping was used for the STFT. The number of iterations for MU updates in all algorithms was 200 for training and 100 for separation. The number of NMF components for each spectral model learned from one example in the universal model was set to 32. Parameters γj for relative block sparsity were set to 1. Parameters λj were set to λ0F N Lj where λ0 was tuned. The number of background components K b in the semi-supervised case was set to 10.

Method

NSDR NSIR Block sparsity (λ0 = 1 × 10

Simulations

To evaluate source separation performance we used the normalized signal-to-distortion ratio (NSDR) and and the normalized signal-tointerference ratio (NSIR) [START_REF] Ozerov | One microphone singing voice separation using source-adapted models[END_REF][START_REF] Vincent | Performance measurement in blind audio source separation[END_REF]. We tested four different methods characterized by block vs. component sparsity and by group sparsity vs. relative group sparsity in both supervised and semi-supervised cases. In the semi-supervised case only one of two keywords was retained for each mixture. The group sparsity penalty parameter λ0 was tuned over a grid for each tested method and λ0 leading to the highest NSDR was retained in each case. Results are summarized in tables 1 and 2. As can be seen, relative group sparsity improves the results over group sparsity in 3 of 4 cases. This is especially significant in the semi-supervised case where an improvement of 0.94 (0.33) dB NSDR is achieved by relative block (component) sparsity over block (component) sparsity; although the source separation performance of all methods drops significantly compared to the supervised case. Finally, as in [START_REF] Badawy | On-the-fly audio source separation[END_REF], we note that component-based sparsity outperforms block-based sparsity owing to its flexibility in choosing the most appropriate spectral components; in particular, the best results in both supervised and semi-supervised cases are obtained by the relative component sparsity method.

CONCLUSION

In this paper, we introduced the notion of relative group sparsity for NMF which prevents some bigger groups (supergroups) of coefficients from converging to zero. We formulated practical criteria and algorithms for relative group sparsity and investigated it within the framework of on-the-fly audio source separation, where supergroups correspond to the universal source models. More specifically, we considered two cases: supervised and semi-supervised. Experiments with mixtures containing various sound types showed that the proposed relative group sparsity outperforms conventional group sparsity in both supervised and semi-supervised settings. Future work may be devoted to the investigation of better ways of choosing λ0 and γj as well as for combing relative block sparsity and relative component sparsity-inducing penalties within the same optimization criterion. In addition, while we examined the notion of relative group sparsity in the context of on-the-fly audio source separation and within the NMF-based approaches, we believe that it can be useful for other dictionary-based signal decompositions.

Fig. 1 .

 1 Fig. 1. Examples of estimated activation matrices H. Left column: (a) block sparsity in the supervised case, (c) component sparsity in the supervised case, and (e) block sparsity in the semi-supervised case. Right column: same settings as in left column, but for the proposed relative block/component sparsity.

Table 1 .

 1 Supervised case: Source separation performances averaged over mixtures.

	-4 )	5.14	9.80
	Component sparsity (λ0 = 1 × 10 -6 )	5.91	10.67
	Relative block sparsity (λ0 = 1 × 10 -4 )	4.78	9.27
	Relative component sparsity (λ0 = 1 × 10 -6 )	6.15	10.70
	Method	NSDR NSIR
	Block sparsity (λ0 = 1)	0.74	4.66
	Component sparsity (λ0 = 2 × 10 -8 )	1.98	6.22
	Relative block sparsity (λ0 = 4 × 10 -4 )	1.68	6.03
	Relative component sparsity (λ0 = 5 × 10 -7 )	2.31	6.64

Table 2 .

 2 Semi-supervised case: Source separation performances averaged over mixtures and keywords.