The Development of Faith in Ganhwa Seon: A Comparative Analysis of Dahui, Gaofeng, and Mengshan

Abstract

Research on Ganhwa Seon has primarily focused on doubt (疑心), whereas systematic comparative studies on faith (信心)—the first element of the Three Essentials (三要) and the basis from which doubt arises—remain limited. This study conducts a comparative textual analysis of the teachings on faith of Dahui Zonggao (大慧宗杲), Gaofeng Yuanmiao (高峰原妙), and Mengshan Deyi (蒙山德異), whose teachings have been transmitted together within the exegetical tradition (講學) of Korean Seon Buddhism. Drawing on Classical Chinese primary sources, Middle Korean vernacular translations with annotations (諺解本, eonhaebon), and English-language scholarship, this study compares the terminology and semantic characteristics of faith, its content, the relationship between faith and doubt, and the conditions and methods for establishing faith in the teachings of the three masters. The analysis shows that Dahui established decisive faith (決定信) and presented a paradoxical coexistence in which both faith and doubt are indispensable to enlightenment. Gaofeng, by applying the essence-function theory (體用論), defined faith as the essence (體) of doubt and enlightenment as the function (用) of doubt, thereby formalizing a proportional structure linking faith, doubt, and enlightenment. Mengshan strengthened the practical dimension through right faith (正信心) and demonstrated that faith determines the quality of doubt by distinguishing true doubt (眞疑) from contrived doubt (做作). All three patriarchs (祖師) shared faith in original Buddhahood (本來成佛) as the central element of faith. This study demonstrates that faith constitutes the ontological basis of doubt and plays a central role in the theory of Ganhwa Seon practice. Furthermore, it shows that the discourse on faith from Dahui through Gaofeng to Mengshan can be reconstructed, on the basis of thematic continuity, as an analytical model that traces how faith was formed, systematized, and practically elaborated, thereby complementing existing discussions that have been disproportionately focused on doubt.

1. Introduction

Ganhwa Seon is a Seon practice method in which practitioners investigate a huatou (話頭) and thereby attain enlightenment. It is generally understood to have taken systematic form in the writings of Dahui Zonggao (大慧宗杲, 1089–1163) of the Song dynasty, where it is known in Chinese as Kanhua Chan (Buswell and Lopez 2014, s.v. Kanhua Chan; Schlütter 2008, pp. 104–16). This tradition, originating with Dahui, continued to be refined in the writings of Gaofeng Yuanmiao (高峰原妙, 1238–1295) and Mengshan Deyi (蒙山德異, 1231–ca. 1308), became a principal practice tradition of Korean Seon Buddhism and continues to be practiced to this day. The essential elements of Ganhwa Seon practice are summarized as the Three Essentials. The Three Essentials, explicitly systematized by Gaofeng Yuanmiao, consist of great faith (大信), great resolve (大憤), and great doubt (大疑): namely, unwavering faith, firm resolve toward enlightenment, and earnest doubt concerning the huatou (Gaofeng Yuanmiao Chanshi Chanyao 高峰原妙禪師禪要, “Instruction to the Assembly, 示眾,” X 70, no. 1401, p. 708b5–11; see Section 4.1).

Among the Three Essentials, the element that has received the greatest scholarly attention is great doubt, that is, doubt itself. This is because the principle of great doubt, great enlightenment (大疑大悟), according to which the greater the doubt, the greater the enlightenment, has long been regarded as a distinctive feature of Ganhwa Seon. However, while discussions centered on doubt have accumulated, inquiry into faith, which occupies the first position among the Three Essentials, has been relatively neglected. Previous studies have shown that, in Dahui’s teachings, both faith and doubt are essential to enlightenment and that the tension between the two constitutes the dynamic of Ganhwa Seon practice (M. Levering 1978, p. 283; Park 1983, p. 66). Yet it has not been sufficiently clarified that faith does not merely coexist with doubt but also functions as the basis from which doubt arises. This foundational role is directly suggested in the teachings of the patriarchs themselves. Park (1983, p. 67), for example, noted that Gaofeng emphasized that, among the Three Essentials, faith must be “as firm and immovable as if leaning against Mount Sumeru (須彌山).” Although great resolve, another element of the Three Essentials, has also been insufficiently studied as an independent topic, clarifying faith, the first element, is an important starting point for a balanced understanding of the Three Essentials as a whole (see Section 6.3).

Building on these observations, this study raises the following four questions. First, through what terms do the three patriarchs—Dahui Zonggao, Gaofeng Yuanmiao, and Mengshan Deyi—conceptualize faith, and what are the semantic characteristics of each term? Second, what content of faith do the three patriarchs present? Third, how do the three patriarchs explain the relationship and interaction between faith and doubt? Fourth, how does each patriarch present the conditions and methods for establishing faith?

This study adopts textual analysis. Since the teachings on faith of the three patriarchs have been transmitted primarily in the form of letters and Dharma discourses, the primary sources are analyzed directly, while English translations are consulted only as supplementary references. The analysis proceeds in four stages. First, terms related to faith used by each patriarch, such as decisive faith (決定信), great root of faith (大信根), and right faith (正信心), are identified, and their semantic characteristics are compared. Second, the specific content of faith presented by each patriarch is identified, and commonalities and differences are examined. Third, the types of relationships between faith and doubt presented by each patriarch, such as paradoxical coexistence, the essence-function relationship, and chain structure, are compared. Fourth, the conditions and methods for establishing faith are identified and compared.

This study analyzes the primary sources in which each patriarch’s discourse on faith and theory of Ganhwa Seon practice are most extensively treated. In the case of Dahui, it draws on the Dahui Pujue Chanshi Shu (大慧普覺禪師書; T 47, no. 1998A, fascs. 25–30), a collection of letters sent to literati officials and monastic practitioners. As M. Levering (1978, p. 243) notes, this collection has continued to serve as a standard text for understanding the basic principles of huatou practice in China, Korea, and Japan. In the case of Gaofeng, this study draws on the Gaofeng Yuanmiao Chanshi Chanyao (高峰原妙禪師禪要; X 70, no. 1401), a compilation of his Dharma talks and letters. This text presents Gaofeng’s theory of faith, including the formalization of the Three Essentials, and, as Buswell (2004, p. 232) notes, is also regarded as one of the Ganhwa Seon texts that presents the role of doubt in a systematic and lucid manner. In the case of Mengshan, this study uses as its base text the Mongsan Hwasang Beobeo Yakrok Eonhae1 (蒙山和尙法語略錄諺解), a Middle Korean translation with annotations of the Mengshan Heshang Fayu Lüelu, published in 1467 by the Gangyeong Dogam (刊經都監).2

This collection of Dharma discourses consists of six instructional sermons that Mengshan delivered to individual practitioners, including “Instruction to Guyuan” (示古原上人), “Instruction to Jueyuan” (示覺圓上人), “Instruction to Weizheng” (示惟正上人), and “Instruction to Cong” (示聰上人). As such, it serves as a manual for the actual practice of Ganhwa Seon that directly conveys concrete instructions concerning faith, doubt, and huatou investigation. Furthermore, the 1467 Gangyeong Dogam edition is textually reliable because the collation of the Classical Chinese text was carried out with precision, making it suitable for analysis in this study. However, because this edition does not include the section “Wanshan Zhengning Chanshi Shi Mengshan fayu” (皖山正凝禪師示蒙山法語), the teachings corresponding to that section are supplemented through Mengshan fayu (蒙山法語, Beopgongyang) by Wonsun (2006).

The Mongsan Hwasang Beobeo Yakrok Eonhae (蒙山和尙法語略錄諺解) consists of the Classical Chinese original text accompanied by Middle Korean gugyeol (口訣)3 reading marks and a vernacular translation. In this article, when citing Mengshan’s teachings, modern Korean translations are presented in the main text, while the Classical Chinese originals are provided in the footnotes. The Classical Chinese text follows the Chinese text of the eonhae edition, but gugyeol markings are omitted for convenience of analysis. The modern Korean translations draw on M.-b. Kim’s (2002) modern annotated edition, Yeokju Mongsan Hwasang Beobeo Yakrok Eonhae (譯註 蒙山和尙法語略錄諺解; King Sejong Memorial Society).

With regard to English translations, this study primarily uses Broughton and Watanabe (2017) for Dahui and refers secondarily to Cleary (1977). Since complete English translations of Gaofeng and Mengshan have not yet been found, this study directly analyzes the Classical Chinese originals while referring to partial translations included in previous studies. Secondary literature is employed in three strands: studies on Ganhwa Seon in English-language scholarship, including Buswell (1991, 2004), M. Levering (1978), Park (1983), and Schlütter (2008); studies by Muller (2016) and Kwon and Woo (2019) for the analysis of essence-function theory; and studies in Korean scholarship, including Ko (2022a, 2022b) and Oh (2024).

Through the above method, this study arrives at the following four conclusions. First, although the three patriarchs refer to faith by different terms—decisive faith (決定信), great root of faith (大信根), and right faith (正信心)—they share both the common content of faith in original Buddhahood and the common quality of unwavering certainty. Second, faith functions as the ontological foundation of doubt, and the three patriarchs explain this relationship, respectively, through the theoretical frameworks of paradoxical coexistence, essence-function theory, and chain structure. Third, the practical ways of cultivating faith are not singular; rather, diverse methods are presented, including the emphasis on faith in oneself, recognition of the urgency of birth and death, observance of precepts, and abandonment of worldly mindedness. Fourth, this study demonstrates that the discourse on faith from Dahui through Gaofeng to Mengshan was progressively refined on the basis of thematic continuity. This study proposes this pattern as an analytical schema of formation, systematization, and practical elaboration. Using the schema, this study seeks to supplement existing discussions that have been overly focused on doubt and to contribute to a balanced understanding of the role of faith in Ganhwa Seon practice theory.

The structure of this article is as follows. Section 2 examines how doubt and faith have been treated in Ganhwa Seon studies and situates this study within existing scholarship. Section 3 analyzes Dahui Zonggao’s concept of decisive faith, Section 4 examines Gaofeng Yuanmiao’s great root of faith (大信根) and the structure of essence-function theory, and Section 5 analyzes Mengshan Deyi’s concepts of right faith and true doubt. Section 6 provides a comparative discussion of the teachings on faith of the three patriarchs, and Section 7 presents the conclusion.

2. Faith and Doubt in Ganhwa Seon Scholarship

2.1. Doubt-Centered Trends in Research

Scholarly research on Ganhwa Seon has largely focused on the role and function of doubt. This tendency is intertwined with the historical transformation whereby the concept of doubt itself, originally regarded in Indian Buddhism as an obstacle to practice, came to be reinterpreted within the East Asian Seon tradition as a driving force for enlightenment (Buswell 2004, p. 226). In particular, Dahui transformed doubt, which his teacher Yuanwu Keqin (圜悟克勤) had regarded as an obstacle to be eliminated, into the central driving force of enlightenment, and this is regarded as Dahui’s distinctive contribution (Buswell 2004, pp. 231–32; Lachs 2012, p. 12).

The central thesis of doubt-centered research is the principle of great doubt, great enlightenment (大疑大悟), according to which the degree of doubt is proportional to the degree of enlightenment. This principle has been widely accepted as the core of Ganhwa Seon practice theory. In this regard, drawing on Kapleau’s insight that the strength of doubt is proportional to the strength of faith, Park (1983, p. 68) argued that investigation arises from the tension between great faith and great doubt. This suggests that inquiry into faith must precede understanding of the operation of doubt.

Research on the nature of doubt has increasingly focused on exploring its internal structure. Buswell (2004, pp. 230–31) argued that, in Ganhwa Seon, doubt functions not as mere cognitive skepticism (懷疑) but as yiqing (疑情), an affective experience that permeates the practitioner’s entire being. Y.-H. Kim (2019, pp. 68, 76) went a step further by distinguishing three dimensions of doubt—fundamental, existential, and methodological. Among these, the dimension directly connected to faith is existential doubt. This is a form of doubt that deepens together with the deepening of faith, and Kim compares this relationship to the way shadows become darker as light grows more intense. This mutually intensifying relationship once again confirms that inquiry into faith is required in order to understand the operation of doubt.

From another angle, Oh (2024, p. 114) drew attention to the differing status among the Three Essentials of Ganhwa Seon and argued that great faith-mind (大信心) and great resolve-mind (大憤心) belong to the category of mental attitudes necessary for practice, whereas great doubt (大疑情) corresponds to the very substance (本體) of practice. The trends described above show that previous studies have converged in positioning doubt as the central element of Ganhwa Seon practice.

2.2. Previous Discussions Concerning Faith (信心)

Even within the broader trend of doubt-centered research, discussions of faith have continued to develop, largely in two directions. One direction seeks to clarify the conceptual characteristics of faith, while the other examines the structural relationship between faith and doubt.

With regard to the conceptual characteristics of faith, the central issue concerns how faith and doubt can coexist within Ganhwa Seon. M. Levering (1978, p. 283), in examining Dahui’s teachings, demonstrated that faith and doubt, though seemingly contradictory, are both indispensable to enlightenment, helping to bring this issue into serious scholarly discussion within English-language scholarship.

This coexistence of faith and doubt is explained differently depending on how faith itself is defined. Park (1983, p. 4) distinguished Seon faith from doctrinal faith (敎信) and defined it as patriarchal faith (祖信) based on the distinction established by Chinul (知訥, 1158–1210)4. Whereas doctrinal faith refers to belief in the possibility of attaining Buddhahood, patriarchal faith actively affirms that one is already a Buddha. From the perspective of patriarchal faith, the practitioner is convinced that one is originally a Buddha while not yet having experientially verified this fact; within this gap, doubt functions instead as a driving force that strengthens faith (Park 1983, p. 73). The view that this concept of patriarchal faith is rooted in Chinul’s understanding of faith is also supported by studies of the Korean Seon tradition. K.-o. Han (2022, pp. 46–47), in reinterpreting Chinul’s understanding-awakening (解悟)5 from the perspective of Tathāgatagarbha (如來藏) thought, presented faith in one’s own mind (自心) as the first element of understanding-awakening. This corresponds to patriarchal faith, namely, the active affirmation that one is already a Buddha.

Significant scholarship has accumulated regarding the structural relationship between faith and doubt. Buswell (2004, p. 234) points out that Gaofeng Yuanmiao positioned faith as the essence (體) of doubt and enlightenment as the function (用) of doubt. He further notes this formulation as drawing on the categories of essence-function theory. Y.-H. Kim (2019, pp. 71–72, 92) connected this structure to the Three Essentials of Ganhwa Seon and suggested that fundamental faith may correspond to great root of faith (大信根), existential doubt to great resolve (大憤志), and methodological doubt to great doubt (大疑情), respectively.

Meanwhile, Lachs (2012, p. 12) focused on the very mechanism through which faith generates doubt. According to his analysis, the practitioner has great faith that he or she has Buddha-nature (佛性), yet does not know this with absolute certainty, and it is precisely this gap that gives rise to doubt. This positions faith as the foundation for the arising of doubt and thus directly connects with the central concern of this study. The analysis of Min et al. (2023, pp. 3, 8) shows that this theoretical structure also operates within contemporary practice settings. They defined great faith, great resolve, and great doubt as the core elements of Ganhwa Seon practice and demonstrated, through an analysis of the instructional methods of Korean Ganhwa Seon masters, that these function as actual components of practice and instruction.

2.3. Research Gap and the Selection of Research Subjects

The foregoing review makes clear the position of this study in three respects. First, as doubt-centered discussions have accumulated, it has become clear that faith must be examined first. This study responds to this need by taking faith itself as the object of analysis. Second, Lachs (2012) proposed a mechanism in which the gap between faith and experiential confirmation gives rise to doubt, and this study systematically clarifies this mechanism across the three patriarchs—Dahui, Gaofeng, and Mengshan. Third, although previous studies have acknowledged the importance of faith, it remains difficult to find studies that systematically compare the concepts of faith in Dahui, Gaofeng, and Mengshan, and discussions concerning either the historical development of discourse on faith or the concrete methodologies for establishing faith are likewise insufficient. Focusing on this gap, this study comparatively examines the three patriarchs’ teachings on faith along four axes—terminology, content, relationship, and method.

This study selects these three patriarchs as its subjects of analysis for two reasons. First, their teachings have been transmitted together within the exegetical tradition (講學) of Korean Seon Buddhism. Dahui’s collection of letters has maintained an important place in Korean monastic education since Chinul (M. L. Levering 2010, pp. 91–92), and both Korean Seon and Japanese Rinzai (臨濟宗) have regarded themselves as inheritors of Dahui’s legacy (Foulk 2000, pp. 23–24). Gaofeng’s Chanyao (禪要, Seon Essentials) was adopted in Korea from the late Goryeo period onward and was included in the Fourfold Collection (四集),6 one of the core instructional texts in Korean monastic education. Mengshan’s Dharma discourses likewise came to be highly valued within Korean Seon circles from the late Goryeo period onward (Cho 2005, p. 176). Second, their teachings on faith provide the richest materials for examining the three dimensions of formation, systematization, and practical elaboration in Ganhwa Seon. Grounded in the texts of the exegetical tradition described above, this study employs this schema as an analytical framework that can be applied retrospectively and does not presuppose a direct teacher–disciple lineage among the three patriarchs. In this respect, this approach shares common ground with Oh (2024), who similarly grouped these three figures together for an integrated examination.

3. Establishing Decisive Faith (決定信): Dahui Zonggao

Dahui Zonggao (大慧宗杲, 1089–1163) was a Seon master of the Yangqi lineage (楊岐派) of the Linji school during the Southern Song dynasty and, as noted in Section 1, played a central role in the systematization of Ganhwa Seon. His discourse on faith was formed within the intellectual-historical context of the controversy with Silent Illumination Seon (默照禪), and Schlütter (2008, pp. 117–19) has shown that the central issue in this controversy concerned the presence or absence of faith in enlightenment. Dahui criticized the followers of Silent Illumination Seon for identifying the stillness of seated meditation with enlightenment itself, thereby closing off the possibility of experiential enlightenment (Schlütter 2008, pp. 117–19).7 In response, Dahui regarded conviction that enlightenment is actually attainable as the first condition that a practitioner must have, and he formalized this conviction through the concept of decisive faith.

3.1. Concept and Terminology in Dahui

Decisive faith (決定信) is the term Dahui used to designate the faith required in Ganhwa Seon practice, and he made clear that the lack of faith constitutes an obstacle to learning the Way. Thus, he stated that “the reason literati often create obstacles for themselves while learning the Way is that they lack decisive faith.”8 Conversely, regarding one who has decisive faith, he offered high praise, saying, “You have decisive faith and are therefore a person of great wisdom.”9

The necessity of decisive faith is repeatedly emphasized in other letters as well. Dahui stated, “If one is determined to attain thorough awakening in this very lifetime, one must not doubt the Buddha, the patriarchs, life, or death; one must therefore possess decisive faith and decisive resolve (決定志).”10 Here, decisive resolve refers to an unwavering determination to attain enlightenment and, paired with decisive faith, forms one of the two central pillars of practice. Furthermore, the structure in which Buddha, patriarchs, life, and death are presented as things that should not be doubted implicitly reflects faith in original Buddhahood, a point that will be examined in Section 3.2.

The nature of decisive faith is also reflected consistently in English-language translations. Cleary (1977, pp. 101–2) renders it as settled faith, while M. Levering (1978, p. 283) defines it as definite, absolute faith, both capturing its unwavering firmness that is not shaken by favorable or adverse circumstances. However, this firmness is not a passive firmness. According to the commentary by Hyesim (慧諶)11 included in Broughton and Watanabe (2017, p. 291), the essential point of Dahui’s letter sent to Vice Minister Rong is that one should instead gain strength in practice precisely when confronted with favorable or adverse conditions. Decisive faith thus does not remain merely an unshaken passive faith but has an active and practical character that transforms both adverse and favorable conditions into the driving force of practice.

3.2. The Content of Faith in Dahui

In Dahui’s teachings, the specific content of faith is revealed through scriptural citation. In the Dahui Pujue Chanshi Shu (大慧普覺禪師書), Dahui expounds the importance of faith by quoting a verse from the “Xianshou Pin” (賢首品)12 of the Avataṃsaka Sūtra (Dafangguang fo huayan jing; 大方廣佛華嚴經). According to the verse, “Faith is the source of the Way and the mother of merit; it nurtures and matures all wholesome dharmas, cuts off the net of doubt, escapes the stream of craving, and reveals the unsurpassed path of nirvāṇa.”13 Here, the expression cuts off the net of doubt (斷除疑網) refers to a type of doubt different from that emphasized in Ganhwa Seon, namely, doubt in the sense of disbelief (不信).

Dahui connected faith and enlightenment at the level of essence. He declared that “the very place reached by faith (信得及處) is precisely the basis for becoming a Buddha or a patriarch.”14 Faith is not merely an external prerequisite for practice but constitutes the inner foundation of attaining Buddhahood.

Dahui’s earlier statements that one “does not doubt the Buddha and does not doubt the patriarchs,” and that “the place reached by faith is precisely the basis of attaining Buddhahood,” imply that the content of faith is belief in original Buddhahood. This implication is expressed even more explicitly in the “Reply to Attendant Lü” (答呂舍人). There Dahui teaches that “naturally, one does not doubt the Buddha, does not doubt the patriarchs, and does not doubt either life or death; when one reaches the ground of no doubt (不疑之地), that itself is the Buddha-ground (佛地).”15 Here, the ground of no doubt is identified with the Buddha-ground that is originally present. Viewed in this light, extending the objects of non-doubt (不疑) to include Buddha, patriarchs, life, and death suggests that the ultimate aim of decisive faith is the unwavering conviction that one is originally no different from the Buddha or the patriarchs.

This faith in original Buddhahood occupies a central place in Seon discourse on faith and reflects the traditional position of faith within Seon thought rather than Dahui’s own original view. For example, Chinul likewise distinguished the right faith of the Patriarchal School (祖師宗) from belief in conditioned causality (有爲的 因果), and regarded the true faith of Patriarchal Seon as the conviction that all people are originally Buddhas and have a flawless self-nature (自性) (Buswell 1991, p. 120).

3.3. The Relationship Between Faith and Doubt in Dahui

Dahui’s teachings reveal the structure within which faith and doubt paradoxically coexist. He stated that “only when one reaches faith (信得及) and sees through thoroughly (見得徹) can one finally become a person who enters and exits birth and death and attains great freedom.”16 The practitioner firmly believes in original Buddhahood (信得及), yet has not yet thoroughly seen it (見得徹), and this very gap becomes the driving force that gives rise to doubt. Faith and doubt exist within a single structure, in which faith provides the foundation from which doubt arises.

As formulated by M. Levering (1978, p. 283), Dahui taught that two apparently contradictory mental attitudes are both indispensable for the path to enlightenment: decisive and absolute faith, and doubt. Only on the basis of firm faith can doubt be transformed into a driving force toward enlightenment.

For this paradoxical coexistence to hold, the doubt spoken of by Dahui must have a character different from mere disbelief. If, in the expression cutting off the net of doubt (斷除疑網) from the Avataṃsaka Sūtra examined in Section 3.2, the doubt to be eliminated refers to skeptical disbelief concerning the Three Jewels and causality, then the yiqing (疑情) that must be generated in Ganhwa Seon refers instead to an investigative question concerning the huatou and functions as a means directed toward enlightenment. Dahui’s originality lies in distinguishing these two types of doubt and positioning the latter at the center of practice.

However, the centrality of doubt does not mean the negation of faith. Doubt unsupported by faith remains merely skepticism, and this point can also be seen in Mengshan’s later distinction between true doubt and contrived doubt (see Section 5.3).

Dahui clearly articulated the relationship between breaking through this investigative doubt and enlightenment. He stated that “if yiqing (疑情) is not broken through, birth and death continue repeatedly; if yiqing is broken through, the mind of birth and death is severed; and when the mind of birth and death is severed, views of Buddha (佛見) and views of Dharma (法見) also disappear.”17 The disappearance of views of Buddha and Dharma has traditionally been regarded in the Seon tradition as a sign of enlightenment, and thus it is explicitly stated that breaking through yiqing leads directly to enlightenment. This is precisely the principle of great doubt, great enlightenment (大疑大悟), expressed in the phrase “beneath great doubt there is necessarily great enlightenment” (大疑之下必有大悟).18

According to M. Levering (1978, p. 301), Dahui expanded Linji’s (臨濟) understanding of doubt in two respects. First, all doubts are in reality a single doubt. Second, the huatou expresses a paradoxical truth that cannot be grasped through ordinary logic, and it serves to arouse doubt when one cannot understand it.

In a letter sent to Attendant Lü Sheren Juren (呂舍人 居仁)19, Dahui stated that “the thousand and myriad doubts are only a single doubt; when doubt concerning the huatou is shattered, the thousand and myriad doubts are shattered all at once.”20 Regarding this, M. Levering (1978, p. 303) pointed out that doubt can break through doubt only when the energy of all doubts is concentrated at a single point, and that this is precisely the function of the huatou.

The most frequently used concrete example of huatou investigation in Dahui’s teachings is Zhaozhou’s (趙州, 778–897)21 Mu (無) huatou.22 When a monk asked Zhaozhou, “Does a dog have Buddha-nature or not?”, Zhaozhou replied, “No (無).” Dahui, in turn, said that this single character was “a sword that cuts through doubt about birth and death.”23 According to Buddhist scriptures, all sentient beings have Buddha-nature. Why, then, did Zhaozhou say “No”? This discrepancy gives rise to doubt in the practitioner’s mind. However, this doubt differs from skepticism that rejects the scriptural teaching itself. When faith in one’s original Buddhahood is grounded in itself, doubt does not develop into skepticism. Rather, it is transformed into the driving force of investigation aimed at breaking through the huatou.

3.4. Methods for Establishing Faith in Dahui

In Dahui’s letters, faith is established through several avenues. First, Dahui arouses faith through scriptural citation. In Letters 16 and 17, Dahui repeatedly cites the verse from the “Xianshou Pin” (賢首品) of the Avataṃsaka Sūtra examined earlier in Section 3.2 in order to expound the importance of faith (Broughton and Watanabe 2017, pp. 131, 134). In addition, in Letter 1, he cites the story of Sudhana (善財童子) from the “Entering the Dharma Realm” chapter (入法界品) of the Avataṃsaka Sūtra, recalling Mañjuśrī Bodhisattva’s teaching to Sudhana that if one departs from the foundation of faith, the mind becomes weak (Broughton and Watanabe 2017, p. 58). By repeatedly citing the verse from the “Xianshou Pin” and invoking the story from the “Entering the Dharma Realm” chapter, Dahui shows that he regarded scriptural teachings as a principal means of establishing faith.

Dahui also urges practitioners to establish both decisive faith and decisive resolve. Only when these two work together does practice gain both driving force and direction. In Letter 17, Dahui compares such faith to something cast from molten iron. He states: “If one resolutely straightens one’s backbone and aspires to become a person unhindered in both worldly and supramundane realms, one must become like iron cast from molten metal (生鐵鑄就底); only then can one accomplish it. If one is half bright and half dark, half believing and half unbelieving, one will definitely not accomplish it.”24

In particular, the most distinctive aspect of Dahui’s discourse on faith lies in faith in one’s own mind, that is, faith in oneself (自信). In Letter 31, Dahui states: “All Buddhas and patriarchs have not a single dharma to give to others; they only require that the individual have faith in oneself, affirm oneself, see for oneself, and awaken for oneself.”25 Self-faith, self-affirmation, self-seeing, and self-awakening may be interpreted not merely as parallel terms but as a fourfold progression, moving from faith to affirmation, from affirmation to seeing, and from seeing to awakening. In this structure, faith appears as an inner conviction concerning one’s own nature. This constitutes a key characteristic distinguishing Dahui from the methods for establishing faith found in Gaofeng and Mengshan. In Letter 53, Dahui invokes the phrase the place reached by faith (信得及處) (Broughton and Watanabe 2017, p. 283). This likewise reaffirms that self-faith ultimately culminates in conviction of the original Buddhahood within oneself.

4. Systematizing the Great Root of Faith (大信根): Gaofeng Yuanmiao

Gaofeng Yuanmiao (高峰原妙, 1238–1295) was a Seon master of the Yangqi branch (楊岐派) of the Linji school active during the Yuan dynasty. He was a disciple of Xueyan Zuqin (雪巖祖欽, ?–1287) (Watanabe 2015, p. 86) and stood within the Ganhwa Seon tradition stemming from Dahui. His discourse on faith is noteworthy in two respects. First, Gaofeng explicitly systematized the structure of the Three Essentials and placed faith in the first position among them. Second, he theorized the relationship between faith and doubt through essence-function theory (體用論), one of the central categories of East Asian thought. This study regards this as the result of reconstructing, in a more highly structured form, the same underlying concern reflected in Dahui’s paradoxical coexistence of faith and doubt.

4.1. Concept and Terminology in Gaofeng

The first of the Three Essentials presented by Gaofeng Yuanmiao is the great root of faith (大信根), that is, the root of great and profound faith. In a Dharma discourse entitled “Instruction to the Assembly” (示眾) in the Gaofeng Yuanmiao Chanshi Chanyao (高峰原妙禪師禪要), Gaofeng first states that “if one truly wishes to practice Seon, one must definitely possess the Three Essentials (三要),” and then explains that “the first essential is to have the great root of faith (大信根); one must clearly recognize this matter (此事) and stand as though leaning on Mount Sumeru (須彌山).”26 In Buddhist cosmology, Mount Sumeru is the mountain forming the central axis of the world. As Buswell (2004, p. 232) explains in citing this passage, the metaphor expresses a solidity “not moved even an inch from one’s faith.” Buswell (2004, p. 232) further argues that Gaofeng’s contribution lay in clearly explaining and systematizing the thought of the existing Linji Seon tradition. Accepting this evaluation, this study argues that Gaofeng’s great root of faith explicitly presents unwavering firmness as a point of reliance (依支處) through the metaphor of Mount Sumeru, whereas Dahui’s decisive faith emphasized firmness unshaken by favorable or adverse conditions (see Buswell 2004, pp. 232–33).

4.2. The Content of Faith in Gaofeng

In Gaofeng’s teachings, the content of faith may be summarized as acceptance of the inherent purity of the original face (本來面目). As discussed in the previous section, Gaofeng takes clearly recognizing this matter (此事) as the point of departure for faith, which means accepting that one’s own nature is originally pure. Faith consists of accepting the immanence of Buddha-nature just as it is, and this faith forms the fundamental basis for attaining enlightenment (see Buswell 2004, p. 233).

This faith in the original face also rests on the same premise of original Buddhahood. Gaofeng did not justify this through any newly formulated doctrinal foundation. Rather, he accepted the teaching of original Buddhahood already established within the Seon tradition in the condensed expression this matter (此事), and established it as the doctrinal foundation of faith by placing it in the first position within the structure of the Three Essentials.

However, merely defining the content of faith as acceptance of original Buddhahood does not by itself clarify the mode of faith. In “Instruction to Layman Xinweng” (示信翁居士), Gaofeng taught that “in Seon practice there is no distinction between monastic and lay; only a single phrase, decisive faith (決定信), is necessary.”27 The term decisive faith (決定信) is the same term used by Dahui in his letters, and it suggests that Gaofeng’s faith has decisive and unwavering conviction as its core. The content of faith is acceptance of original Buddhahood, while its mode is decisive faith.

4.3. The Relationship Between Faith and Doubt in Gaofeng

This study pays particular attention to Gaofeng’s formalization of the relationship between faith and doubt through essence-function theory. Essence-function theory (體用論) is a central category in East Asian thought dealing with the relationship between essence (體) and function (用).28

Gaofeng explicitly articulated this relationship in terms of essence-function theory in “Instruction to Layman Xinweng” (示信翁居士). He taught as follows: “You must decisively believe and doubt in this way. Thus you must clearly understand that doubt takes faith as its essence (體), while enlightenment takes doubt as its function (用) (疑以信爲體, 悟以疑爲用).”29 On the basis of this passage, Buswell (2004, p. 234) pointed out that Gaofeng regarded faith as the essence of doubt and enlightenment as the function of doubt, and that this formulation draws on the categories of essence-function theory established in the Awakening of Faith in the Mahāyāna (Dasheng qixin lun; 大乘起信論). This study accepts Buswell’s observation and understands Gaofeng’s formulation as a more highly structured result, within the framework of essence-function theory, of the paradoxical coexistence already observable in Dahui.

At this point, however, care must be taken not to confuse the meaning of the term essence (體). In the analysis by Oh (2024, p. 114) examined in Section 2.1, great doubt was defined as the substance (本體) of Ganhwa Seon, but there the term substance refers to the claim that great doubt is the central element among the Three Essentials. By contrast, when Gaofeng states that “doubt takes faith as its essence (體)” (疑以信爲體), he refers to the essence-function relationship in which doubt takes faith as its substance (本體, foundational essence). The same Chinese character ti (體) is thus being used on two different levels: one as positional centrality and the other as structural foundation. If this distinction is overlooked, there is a danger that Gaofeng’s contribution through essence-function theory may be reduced merely to a reaffirmation of the importance of doubt.

Gaofeng further clarified the relationship among faith, doubt, and enlightenment following the above essence-function formulation. The very next sentence of the same passage states this concisely: “when faith is full (十分), doubt is likewise full; when doubt is full, enlightenment is likewise full.”30 By presenting the essence-function relation and the proportional relation within a single continuous statement, Gaofeng declares that faith, doubt, and enlightenment stand in a directly proportional relationship.

This proportional relationship extends the principle of great doubt, great enlightenment. What Park (1983, p. 68) observed in Dahui as a proportional relationship between faith and doubt is extended by Gaofeng to enlightenment itself, thus forming a triadic proportional structure of faith-doubt-enlightenment (see Buswell 2004, p. 234). Within this structure, doubt does not negate faith but instead functions as the fuel of faith, deepening it dynamically (Park 1983, p. 73).

4.4. Methods for Establishing Faith in Gaofeng

If faith consists of accepting original Buddhahood and stands in an essence-function relationship with doubt, then how is such faith established? Gaofeng emphasized that doctrinal acceptance alone is insufficient and that faith becomes truly dynamic only when joined to an existential motivation. In “New Year’s Eve Informal Instruction” (除夜小參), he declared: “The matter of birth and death is great, and impermanence is swift. Being born without knowing from where one has come is called the greatness of birth (生大), and dying without knowing where one goes is called the greatness of death (死大).”31 In this way, he stressed the existential urgency of birth and death. According to Gaofeng, the Buddhas of the three times appear in the world, successive patriarchs transmit the Dharma, and Seon monks throughout the monasteries practice all for the sake of resolving the fundamental matter of birth and death (see X 70, no. 1401, pp. 709c18–22). When practitioners recognize that their own existential concern is situated within this tradition, the existential foundation of faith is formed.

Gaofeng also warned of the danger arising from insufficient faith, stating that “if this mind is not earnest, true doubt (眞疑) will not arise.”32 In other words, the earnestness of faith is the precondition for the arising of yiqing, and this very warning also functions as a means of encouraging the practitioner’s faith.

Although Gaofeng emphasized the urgency concerning the matter of birth and death (生死心切) and maintained terminological continuity with Dahui through the expression decisive faith (決定信), he distinguished himself from Dahui by structurally establishing the status of faith within the framework of the Three Essentials. However, as Oh (2024, p. 115) has pointed out, Gaofeng’s system of practice lacked concrete practical instructions and therefore did not fully systematize how practitioners should establish faith. It is precisely this practical elaboration that appears prominently in the teachings of Mengshan Deyi.

5. The Practice of Right Faith (正信心): Mengshan Deyi

Mengshan Deyi (蒙山德異, 1231–ca. 1308) was active during the same Yuan period as Gaofeng but belonged to a different Dharma lineage, inheriting the Dharma of Wanshan Zhengning (皖山正凝) (Watanabe 2015, p. 78). His discourse on faith is noteworthy in two respects. First, through the new term right faith (正信心), he emphasized the rightness of faith by stressing the union of faith and observance of precepts (持戒). Second, through the distinction between true doubt and contrived doubt, he elucidated the mechanism by which faith determines the quality of doubt. Mengshan’s Dharma discourses were transmitted to Korea in the late Goryeo period through Naong Hyegun (懶翁慧勤) (Itō 2023, p. 166), eventually extending to the vernacular editions published by the Joseon Gangyeong Dogam and coming to occupy a central place within the Korean Seon tradition.

5.1. Concept and Terminology in Mengshan

Mengshan developed his discourse on faith in a more practically elaborated form. In his teachings, practical instructions concerning how faith is to be aroused and how it is to be carried forward into doubt are formulated in much more concrete terms (see Oh 2024, pp. 115–16). The starting point of this formulation is the term right faith (正信心) presented in the Mongsan Hwasang Beobeo Yakrok Eonhae (蒙山和尙法語略錄諺解), through which Mengshan conceptualized the faith required in Ganhwa Seon practice.

In “Instruction to Guyuan” (示古原上人), Mengshan states: “Only when one fully arouses right faith (正信心), and within the true mind (眞心) there is doubt, will the huatou naturally appear before one.”33 Having right faith thus becomes the foundation for the manifestation (現前) of the huatou.

The same teaching is repeated in “Instruction to Weizheng” (示惟正上人). Mengshan states: “Fully arouse right faith, cast away all worldly mindedness (世間心), and hold the huatou with clarity and meticulousness; then, while sitting, one will most easily gain strength.”34 Here, right faith arises together with the abandonment of worldly mindedness, and only when these two conditions are fulfilled does practice gain strength.

Compared with Dahui’s use of decisive faith and Gaofeng’s use of the great root of faith, Mengshan’s right faith emphasizes rightness (正). The concrete content of this rightness lies in its accompanying observance of precepts. Mengshan’s teacher Wanshan (皖山) taught that even if faith had been established, one must still uphold the precepts (戒), and accordingly Mengshan stated that he himself observed the Five Precepts (五戒) (see Oh 2024, p. 171). For Mengshan, right faith means faith accompanied by observance of precepts. Within the limits of the materials analyzed in this study, Mengshan alone among the three patriarchs explicitly mentions this point in the context of his discourse on faith (the practical significance of observance of precepts is analyzed in Section 5.4).

5.2. The Content of Faith in Mengshan

Like Dahui and Gaofeng, Mengshan takes belief in original Buddhahood as the core of faith. This is observed in “Instruction to Jueyuan” (示覺圓上人), where Mengshan states: “If original awakening (本覺) has not yet become clear, one must raise doubt about each and every thing.”35 The use of the term original awakening (本覺) implies the premise that all sentient beings inherently possess the nature of enlightenment from the beginning. When the practitioner considers that “original awakening has not yet become clear,” this does not indicate the absence of original awakening but rather a state in which it has not yet been experientially verified.

However, the distinctive feature of Mengshan’s right faith lies in the fact that it places the content of faith within the practical context of cultivation rather than describing it at the level of abstract doctrine. Whereas Dahui clarified the doctrinal foundation of faith through quotations from the Avataṃsaka Sūtra, and Gaofeng theorized it through the structure of essence-function theory, Mengshan presents faith in the form of a practical imperative: fully arouse right faith (發盡正信心). This means that Mengshan transforms faith, grounded in the doctrinal premise of original awakening (本覺), into an active function to be manifested in the field of practice.

Although all three patriarchs transmitted their thought in the form of teachings for actual practitioners, the rhetorical mode through which they present faith differs from one another. Dahui appeals for the establishment of faith through scriptural citation and exhortation, while Gaofeng defines the status of faith through essence-function formulation. By contrast, Mengshan directly presents faith as an act that the practitioner must actualize here and now through the imperative expression fully arouse (發盡). This practice-oriented character remains consistent throughout Mengshan’s entire theory of cultivation.

5.3. The Relationship Between Faith and Doubt in Mengshan

Not all forms of doubt are the same within Ganhwa Seon practice. According to Ko (2022b, p. 118), the essential key to Mengshan’s actual practice (實參) consists of arousing true doubt-mind (眞疑心) toward the huatou with a right mind, together with uninterrupted, lucid and meticulous (惺惺密密) investigation. Among these, the problem of arousing true doubt-mind is directly connected to faith, and Mengshan presents this point clearly at the beginning of “Instruction to Guyuan”: “If doubt on the huatou does not cease, this is called true doubt (眞疑). But if one doubts briefly and then doubt disappears again, this is not doubt arising from the true mind (眞心) but belongs to contrivance (做作).”36

Here the distinction between true doubt and contrived doubt emerges. True doubt is doubt that naturally arises from the true mind (眞心), which has been brought forth through the full arousal of right faith, and that continues without interruption. Contrived doubt, by contrast, is temporary doubt artificially produced through external determination alone, without the foundation of faith. The distinction between the two is not merely a difference in degree but a difference in the source of their arising. This difference produces decisive consequences for the continuity of practice. As Ko (2022b, p. 128) points out, Mengshan warned that in the case of doubt arising through contrived doubt, the huatou easily disappears, and torpor (昏沈) and distraction (掉擧) could intrude through such gaps. As a corresponding claim, this study further infers that in true doubt, which continues without interruption, no space remains for torpor and distraction to intrude.

Viewed in this light, the intrusion of torpor and distraction during practice may function as a diagnostic sign revealing that one’s doubt has not yet reached the level of true doubt.

Then from where does true doubt arise? The phrase fully arouse right faith (發盡正信心), examined in Section 5.1, provides the answer. This phrase shows a chain structure—this study’s term for Mengshan’s configuration of right faith, true mind, and true doubt—in which right faith must be aroused for the true mind to be established, and doubt then arises from that true mind. Only when right faith becomes the foundation of the true mind does true doubt become possible.

This chain structure is connected to the concept of turning the light around to look back at oneself (廻光自看). Mengshan’s teacher Wanshan Zhengning (皖山正凝) taught that when investigating the Mu (無) huatou, “whenever doubt arises, one should silently attend to this Mu huatou and turn the light around to look back at oneself (廻光自看).”37 Inheriting this teaching, Mengshan emphasized turning doubt not outward but inward toward the mind itself (see P.-r. Kim 2023, p. 141). Yet in order to turn doubt inward, there must first be an inward place to which it can return, namely, conviction concerning one’s originally awakened nature. This conviction is right faith. If one turns doubt inward without right faith, it merely becomes contrived doubt.

Mengshan likewise shares with Dahui and Gaofeng the same principle of great doubt, great enlightenment. The teaching from “Instruction to Jueyuan” (示覺圓上人) cited in Section 5.2 is extended in the following passage into the principle of great doubt and great enlightenment. Mengshan teaches: “If original awakening has not yet become clear, one must raise doubt about each and every thing; if one greatly doubts, then there will be great enlightenment.”38 This study regards the principle that originated with Dahui and was formalized by Gaofeng into a triadic proportional structure of faith, doubt, and enlightenment as an interpretive framework equally applicable to Mengshan’s schema of right faith and true doubt. Mengshan’s schema may likewise be reconstructed as a chain structure in which the deeper the right faith, the deeper the true doubt, and the greater the enlightenment. However, it should be clearly noted that the explicit formulation of proportionality belongs to Gaofeng and not to Mengshan himself. What is clear in Mengshan’s teachings is that doubt must be true doubt grounded in right faith, and that contrived doubt cannot lead to enlightenment.

5.4. Methods for Establishing Faith in Mengshan

If right faith is the foundation of true doubt, then how is such right faith established? In response to this question, Mengshan presents more concrete practical instructions than the other two patriarchs. Whereas Dahui and Gaofeng concentrated on establishing the status and structure of faith, Mengshan provided multilayered practical guidance concerning how faith is to be manifested and how it is to be maintained within daily life.

The first concrete method for establishing right faith is observance of precepts. As confirmed in the anecdote concerning Wanshan and Mengshan, Mengshan concretized the rightness of right faith through the reception and observance of the Five Precepts (五戒). Observance of precepts functions as a mediating practice that transforms faith from superficial determination into embodied daily practice. In this respect, Mengshan’s right faith does not remain at the level of volitional resolve but is established as a faith continuously sustained within daily conduct.

The second method is the abandonment of worldly mindedness. In the teaching from “Instruction to Weizheng” (示惟正上人) cited above, arousing right faith is presented as a simultaneous task together with the removal of attachment to worldly concerns. If faith is not separated from worldly standards of value, that faith will fluctuate according to external conditions. By pairing the establishment of right faith with the abandonment of worldly mindedness, Mengshan explicitly presents the condition necessary for faith to attain self-sufficiency unshaken by external circumstances.

The third method is the Middle Way mode of directing the mind (中道的 用心). In “Instruction to Weizheng” (示惟正上人), Mengshan states that “the subtlety lies in using the mind well,” thereby emphasizing the importance of how to direct the mind.39 He also states: “Directing the mind must not be too urgent; if urgent, it agitates the body–mind (色心) and illness arises. Nor must it be too lax; if lax, one forgets the huatou and falls into torpor and distraction (掉擧).”40 If one is overly urgent, illness results; if overly lax, one forgets the huatou and may fall into the contrived doubt discussed in Section 5.3. The practice of turning the light around to look back at oneself (廻光自看), discussed above as turning doubt inward toward the mind rather than outward, also becomes possible only when this Middle Way mode of directing the mind is established. The presentation of such concrete practical instructions itself functions as a means of supporting the practitioner’s faith.

6. Discussion

6.1. Comparative Overview of the Teachings on Faith in Dahui, Gaofeng, and Mengshan

Through the analyses presented in Section 3, Section 4 and Section 5, the teachings on faith of Dahui Zonggao, Gaofeng Yuanmiao, and Mengshan Deyi were examined according to the four axes introduced in Section 1—the semantic characteristics of the terms for faith, the content of faith, the relationship between faith and doubt, and the methods for establishing faith. The results are summarized in Table 1. Since all three patriarchs present the content of faith in the form of belief in original Buddhahood, it is not presented as a separate row in Table 1; only the three differentiating axes are compared.

Table 1. Comparison of Faith Teachings in Dahui, Gaofeng, and Mengshan.

Category	Dahui Zonggao	Gaofeng Yuanmiao	Mengshan Deyi
Term for Faith	Decisive faith (決定信)	Great root of faith (大信根); decisive faith (決定信)	Right faith (正信心)
Semantic Features of the Term	Unwavering firmness amid favorable and adverse conditions	A point of reliance as immovable as Mount Sumeru	Emphasis on rightness (正); accompaniment by observance of precepts
Faith–Doubt Relationship	Paradoxical coexistence (both required)	Essence–function theory and proportional relationship	Right faith (正信心) gives rise to the true mind (眞心), from which true doubt (眞疑) arises
Methods of Establishment	Scriptural teachings and the instructions of spiritual teachers; establishment of decisive faith and decisive resolve (決定志); emphasis on faith in oneself (自信)	Full acceptance of the inherent presence of Buddha-nature; recognition of the existential urgency of birth and death	Arousal of right faith and abandonment of worldly mindedness (世間心); observance of precepts (持戒); Middle Way mode of directing the mind (用心); guidance from spiritual teachers

6.2. The Mechanism of Faith, Doubt, and Enlightenment

The clearest common feature running through the teachings of the three patriarchs is that all regard faith as an indispensable prerequisite for Ganhwa Seon practice. Although the terminology differs—decisive faith (Section 3.1), the great root of faith (Section 4.1), and right faith (Section 5.1)—all three patriarchs share the recognition that doubt cannot even arise without faith. This proposition was expressed in its most explicit formulation by Gaofeng through the categories of essence-function theory (Buswell 2004, p. 234), and the same structure also operates in the teachings of Dahui and Mengshan. Furthermore, all three patriarchs regard unwavering firmness as the central attribute of faith. In addition, all three understand faith and doubt not as oppositional but as interconnected, as seen respectively in Dahui’s paradoxical coexistence (Section 3.3), Gaofeng’s explanation in terms of essence-function theory (Section 4.3), and Mengshan’s chain structure moving from right faith to true doubt (Section 5.3).

The faith taught by the three patriarchs also shares belief in original Buddhahood as its core content. This tradition can be traced back as far as Bodhidharma’s Treatise on the Two Entrances and Four Practices (二入四行論). According to McRae (2003, pp. 29–30), this text proclaims deep faith that all sentient beings possess the same Buddha-nature. If Park’s (1983, p. 4) distinction between doctrinal faith (敎信) and patriarchal faith (祖信), examined in Section 2.2, is applied to the analysis of this study, then the faith of all three patriarchs corresponds to patriarchal faith. That is, it goes beyond merely acknowledging the possibility of attaining Buddhahood and instead affirms that one is originally a Buddha, which constitutes the core of Seon discourse on faith, as confirmed in Section 3.2 (Buswell 1991, p. 120).

This faith in original Buddhahood is doctrinally connected to Tathāgatagarbha and Buddha-nature thought. Mengshan’s use of the term original awakening (本覺) (Section 5.2) and Chinul’s presentation of faith in one’s own mind as the first element of understanding-awakening (K.-o. Han 2022, pp. 46–47) both rest on the same doctrinal foundation.

Based on this common foundation, the processes for establishing faith taught by the three patriarchs may be synthesized as follows. As discussed by Park (1983, pp. 6, 73), faith and doubt form a dialectical tension within koan (公案) practice, and in this process doubt in turn strengthens faith (see Section 2.2 and Section 4.3). The point of departure lies in encountering the teaching of original Buddhahood. The gap between the belief that one is originally a Buddha and the absence of its direct experience gives rise to doubt (see Section 3.3), and the doubt thus generated flows back into faith, thereby deepening it.

This principle appears in different forms within the teachings of the three patriarchs. In Dahui, this gap is concretized as the distance between reaching faith (信得及) and seeing through thoroughly (見得徹). Gaofeng applied a logic of proportionality to this relationship. That is, the depth of faith determines the depth of doubt, and the depth of doubt in turn determines the depth of enlightenment.

Mengshan’s contribution lies in clarifying the case in which this process fails. Doubt generated without right faith cannot become true doubt and remains at the level of contrived doubt.

In short, the three patriarchs clarified different aspects of the same principle. Gaofeng’s proportional relationship provided a theoretical formulation for Dahui’s structure, while Mengshan’s distinction between true doubt and contrived doubt clarified under what conditions this structure functions and under what conditions it fails.

6.3. The Status of Faith Within the Structure of the Three Essentials

The principle elucidated in Section 6.2 is directly connected to the question of what status faith occupies within the structure of the Three Essentials. In the structure of the Three Essentials formalized by Gaofeng—great root of faith, great resolve, and great doubt—the fact that the great root of faith is presented as the first element reflects the sequence according to which faith must first be established. Only when faith has first been established can resolve and doubt arise rightly.

In the “Instruction to the Assembly” (示眾) discourse cited in Section 4.1, after presenting the great root of faith, the great resolve, and great doubt, Gaofeng states that “if even one of these three is lacking, it is like a cauldron with a broken leg and in the end becomes useless,” thereby clarifying that all three essentials must be fully present. However, the fact that all three are necessary does not mean that they arise simultaneously. As seen above, Gaofeng made it clear that the earnestness of faith is the precondition for the arising of true doubt, and this is the natural conclusion flowing from the structure of essence-function theory.

This priority of faith is not inconsistent with the analysis of Oh (2024, p. 114) examined in Section 2.1. To say that great doubt corresponds to the substance of practice means only that it constitutes the central function of practice; it does not mean that it arises first chronologically. Only if the great root of faith is first established as a mental attitude can great doubt come to function as the central operation of practice. That is, these two are compatible precisely because they belong to different levels: great doubt’s status as the central function and faith’s chronological priority.

Meanwhile, Y.-H. Kim’s (2019) correspondence between the Three Essentials, examined in Section 2.2—fundamental faith ↔ great faith, existential doubt ↔ great indignant resolve, and methodological doubt ↔ great yiqing—is compatible with this study in two respects. First, his recognition of fundamental faith—namely, belief in Buddha-nature—as an essential foundation across both Patriarchal Seon and Ganhwa Seon (Y.-H. Kim 2019, p. 92) aligns with this study’s proposition that faith has a foundational status in Ganhwa Seon practice theory. Second, his characterization of existential doubt as a doubt that deepens together with the deepening of faith (Y.-H. Kim 2019, p. 76) has the same structure as this study’s explanation that faith functions as the basis for the arising of doubt. The two studies differ, however, in their choice of basic analytical categories. Kim’s framework takes a typology of doubt as its primary analytical category, treating faith as a concept paired with fundamental doubt and even understanding great resolve as a dimension of doubt (Y.-H. Kim 2019, p. 92). By contrast, this study establishes faith as a distinct category separate from doubt and positions it as the foundation from which doubt arises.

Modern scholarly interpretations also support this understanding. Subul Sunim (2010, p. 30) defines Ganhwa Seon as “a practice method in which an enlightened Seon master enables one who has generated faith to arouse true doubt through huatou investigation and thereby attain sudden enlightenment,” thus explicitly indicating that faith is a prerequisite for huatou investigation. Likewise, J.-K. Han (2011, p. 143) defines great faith as conviction in enlightenment, namely, the conviction that “I too can do it,” and presents it as an essential requirement for the practice of Ganhwa Seon. As shown through essence-function theory and the proportional relationship, faith is the foundation that supports doubt and enlightenment and thereby sustains the entire structure of the Three Essentials.

This status is shared by all three patriarchs. Gaofeng systematized this foundational status of faith by explicitly placing it in the first position within the structure of the Three Essentials.

6.4. The Progressive Refinement of Discourse on Faith: An Analytical Schema of Formation, Systematization, and Practical Elaboration

Although the three patriarchs share a common principle, they each developed their discourse on faith in different directions. This study reconstructs this pattern as a progressive schema of formation, systematization, and practical elaboration. These stages appear most clearly in the transformation of terminology. Decisive faith, established by Dahui, continued to be used by Gaofeng, where it was combined with the new designation great root of faith within the structure of the Three Essentials. By the time of Mengshan, it had developed into the new term right faith (正信心), which emphasized rightness (正) and the accompanying observance of precepts as essential requirements of faith.

Beyond the level of terminology, shared phrasing can also be identified. Dahui expressed the unity of doubt through the phrase “the thousand and ten thousand doubts are only a single doubt” (千疑萬疑, 只是一疑) (Dahui Pujue Chanshi Shu, T 47, no. 1998A, p. 930a14–15), and the same phrase also appears in Gaofeng’s “Instruction to Layman Xinweng” (Gaofeng Yuanmiao Chanshi Chanyao, X 70, no. 1401, p. 707a11). This suggests that the analytical schema employed in this study has a certain basis in the actual sharing of textual phrasing. However, the sharing of phrasing alone does not prove direct master-disciple transmission, and this remains a task for future intellectual-historical research.

Likewise, a pattern of progressive refinement appears in their configuration of the relationship between faith and doubt. Dahui presented their paradoxical coexistence; Gaofeng formalized this through essence-function theory and a proportional relationship; and Mengshan presented a chain structure moving from right faith through true mind to true doubt. The structure observable in Dahui becomes more systematically organized through essence-function theory in Gaofeng’s texts and is further concretized as a practical chain structure in Mengshan’s texts. This pattern of refinement may be understood not so much as the result of direct influence among the three patriarchs but rather as the outcome of different forms of refinement applied to a shared concern at the level of distinct textual materials.

The elements combined with faith also differ according to each patriarch. Dahui emphasized faith in oneself, Gaofeng emphasized an awareness of the urgency of life and death, and Mengshan emphasized the abandonment of worldly mindedness together with observance of precepts. These differences are also related to the historical contexts in which the respective patriarchs were active. Whereas Dahui, in the Southern Song period, emphasized the unwavering firmness of decisive faith within the context of controversy with Silent Illumination Seon, Gaofeng, active during the Yuan dynasty, inherited Dahui’s lineage and moved toward theoretical systematization, while Mengshan, belonging to a different lineage, moved toward the establishment of practical instructions. Accordingly, this study reconstructs the corpus of discourse on faith in Ganhwa Seon through the analytical schema of formation (Dahui), systematization (Gaofeng), and practical elaboration (Mengshan).

6.5. Practical Implications

The practical implications derived from the preceding mechanism and historical development are clear. The fact that only true doubt arising from right faith can lead to enlightenment means that the establishment of faith determines the quality of doubt and ultimately conditions the possibility of enlightenment.

This analysis also carries implications for the contemporary guidance of Ganhwa Seon practice. The establishment of great faith remains a major component within contemporary Korean Ganhwa Seon training (Min et al. 2023, pp. 5, 8), and, in particular, Mengshan’s distinction between true doubt and contrived doubt provides practical criteria for meditation instructors to assess whether a practitioner’s doubt is grounded in faith.

This criterion also has historical significance. Scholarship has long pointed out that, after the Song dynasty, East Asian Seon became increasingly intertwined with literati culture, resulting in prominent literary engagement with koans through poetry and prose (see Cho 2025, pp. 81, 90). Mengshan regarded a koan (huatou) as the object of investigation through which one arouses right faith (正信心) and gives rise to true doubt (眞疑) from within the true mind (眞心).41 However, his recorded sayings contain no direct criticism of the literary use of koans. Rather, his criticism is directed at an intellectual approach that attempts to interpret and analyze koans through language, as well as at contrived doubt (做作) that does not arise from the true mind. This study therefore draws attention to the fact that Mengshan’s distinction between true doubt and contrived doubt was presented in the midst of this historical tendency, and suggests that this distinction may be read as an internal criterion intended to guard against the substitution of formal imitation for the substance of practice. In this respect, the discourse on faith developed by the three patriarchs remains even today as an internal standard through which Ganhwa Seon can preserve its practice-oriented character.

7. Conclusions

This study analyzed the teachings of Dahui Zonggao, Gaofeng Yuanmiao, and Mengshan Deyi in order to clarify the role of faith in Ganhwa Seon practice. The central finding revealed through the analysis is that, despite differences in terminology and emphasis, the discourse on faith developed by the three patriarchs shares a common structure while simultaneously showing a progressive refinement that this study reconstructs through the analytical schema of formation, systematization, and practical elaboration. First, despite the differences in the terms decisive faith, great root of faith, and right faith, the three patriarchs share the same understanding of faith: it consists in a firm belief in original Buddhahood and is characterized by unwavering firmness.

Second, all three patriarchs made it clear that faith is the ontological foundation of doubt. Dahui’s paradoxical coexistence, Gaofeng’s explanation in terms of essence-function theory, and Mengshan’s chain structure moving from right faith to true doubt employ different theoretical frameworks, but all converge on the same principle. The teachings of the three patriarchs also show a shared understanding that scriptures and Dharma teachings function as occasions for faith, and that established faith does not exclude doubt but rather makes genuine doubt possible.

Third, with respect to the ways in which faith is established, the three patriarchs each emphasized different elements. Dahui emphasized faith in oneself, Gaofeng emphasized recognition of the urgency of birth and death, and Mengshan emphasized observance of precepts together with the abandonment of worldly mindedness, thereby demonstrating that the practical paths for establishing faith are not singular.

Fourth, the preceding discourse on faith may be reconstructed as a pattern in which Dahui’s materials articulate decisive faith, Gaofeng’s materials systematize this discourse through the structure of the Three Essentials and essence-function theory, and Mengshan’s materials give it practical form through the distinction among right faith, true doubt, and contrived doubt. This study adopts this stage-based schema as an analytical framework distinct from a theory of intellectual-historical influence.

This study supplements the existing tendency to understand Ganhwa Seon primarily as a practice of doubt. In particular, Gaofeng’s formulation, “doubt takes faith as its essence, and enlightenment takes doubt as its function” (疑以信爲體, 悟以疑爲用), explicitly indicates that faith is not merely the basis for the arising of doubt but is also structurally linked to doubt within the framework of essence-function theory, one of the central categories of East Asian thought. This makes it possible to move beyond readings that interpret faith merely as an attitudinal prerequisite. Furthermore, this study traced the continuous refinement of discourse on faith from Dahui through Gaofeng to Mengshan. Since Gaofeng shared with Dahui the same term decisive faith, and Mengshan further concretized its practical dimension through the concept of right faith, the analysis confirms that discourse on faith in Ganhwa Seon may be reconstructed, on the basis of thematic continuity, through the analytical schema of formation, systematization, and practical elaboration.

Nevertheless, one limitation of this study is that all three patriarchs developed their discussions on the presupposition of already established faith; consequently, the process through which faith matures, as well as methods for responding to the loss of faith, were not sufficiently clarified. Future research should address this issue, while also undertaking a more rigorous comparison between Y.-H. Kim’s (2019) correspondence framework of the Three Essentials and the foundational analysis proposed in this study, a task deferred in Section 6.3. Moreover, since the coexistence of faith and doubt is not limited to Ganhwa Seon alone, comparative studies with other religious practice traditions may likewise be possible. It is hoped that this study will contribute to a balanced understanding of the role of faith in Ganhwa Seon practice theory.