1. Introduction

The Tang Dynasty (618–907) marked a golden age in Chinese history, characterized by political stability, economic prosperity, and remarkable cultural development. During this period, Mahāyāna Buddhism, which had entered China centuries earlier, had undergone significant transformation, resulting in a distinctly Chinese form that blended Indian doctrine with indigenous Chinese philosophical and institutional traditions [1]. Tang Buddhism became deeply embedded in state ideology and cultural life, while the dynasty’s openness to foreign exchanges facilitated its transmission abroad. Among the regions most influenced were Japan and the Korean Peninsula, where Buddhism was received, adapted, and localized according to local political and cultural contexts. This study focuses on the reception of Tang Buddhism from the 7th to the 10th centuries with particular attention to Japan and the Silla kingdom of Korea. In Japan, transmission coincided with the Asuka, Nara, and early Heian periods, while on the Korean Peninsula, Tang influence overlapped with Silla’s unification and consolidation of power after conquering Goguryeo and Baekje in the 7th century [2, 3].

Existing scholarship has explored this topic along three main strands: studies of transmission routes such as embassies, monks, and texts; research on the intellectual history of sects and doctrines, including Tiantai and Huayan; and country-specific chronologies that trace institutional development. While valuable, these approaches often remained fragmented, adopting a single-dimensional or region-specific perspective—for example, focusing exclusively on Japan or solely on Silla—without a comparative framework that places both within the same analytical scope.

This paper seeks to address that gap by employing a threefold analytical framework—sect, doctrine, and institution—to examine how Japan and Silla received, reshaped, and localized Tang Buddhism. Through comparative analysis, the study highlights the dynamic interplay between religious transmission, state power, and cultural adaptation in East Asia during the Tang period.

2. Buddhism in the Tang Dynasty: sects, doctrines, and institutions

Within the context of sustained cross-regional interaction, the development of Buddhism in Japan and on the Korean Peninsula drew heavily upon Tang Buddhist models and practices. To better understand the scope of this influence, it is necessary to provide a concise overview of Buddhism during the Tang period. Broadly speaking, Tang Buddhism can be analyzed along three interrelated dimensions. The first concerns the formation and evolution of sects, which demonstrate the scholastic diversification and systematization of Buddhism in China. The second is doctrinal development, reflecting both the assimilation of Indian Buddhist philosophy and its accommodation to Chinese intellectual traditions. The third is institutional construction, whereby Buddhist monasticism became embedded within state structures and social practices. Together, these dimensions offer a comprehensive picture of Tang Buddhism and the foundation upon which its transmission to neighboring regions was built.

2.1. The development of sects

During the Tang period, Buddhism reached a new stage of maturity in terms of doctrinal development, sectarian formation, and institutional organization. Mount Wutai, venerated as the bodhimaṇḍa of Mañjuśrī, became one of the most revered sacred sites for pilgrimage, religious exchange, and scholarly interaction with neighboring states [1]. Among the numerous schools of the time, the Tiantai and Huayan schools emerged as particularly influential.

The Tiantai school, originating from Mount Tiantai in present-day Zhejiang, was systematized by the monk Zhiyi (538–597) [4]. Centering its teachings on the Saddharmapuṇḍarīka (Lotus Sutra), Tiantai emphasized the doctrines of “One Vehicle” (ekayāna) and “skillful means” (upāya). Zhiyi’s works—Profound Meaning of the Lotus Sūtra, Great Calming and Contemplation (Mohe Zhiguan), and Words and Phrases of the Lotus Sūtra (Fahua Wenju)—were later canonized as the “Three Great Tiantai Treatises.” [5] The Huayan school, which rose to prominence in the subsequent period of the Tang, similarly structured its thought around a central scripture, the Avataṃsaka Sūtra (Huayan jing), while also drawing upon the Sūtra of Perfect Enlightenment (Yuanjue jing) and the Awakening of Faith in the Mahāyāna (Dasheng qixin lun). It taught the doctrine of the interpenetration of all phenomena within the Dharma realm and upheld the belief that all sentient beings inherently possess Buddha-nature and have the potential to attain Buddhahood [4]. Overall, Tang Buddhism witnessed remarkable prosperity in its doctrinal systems, sectarian institutions, and monastic networks.

2.2. Doctrinal features

By the Tang period, Chinese Buddhism had undergone extensive sinicization and thus differed in important respects from its Indian antecedents. Rather than a mere transplantation of Indian doctrines, Buddhist thought in Tang China constituted a localized idiom that integrated indigenous intellectual resources and state institutions [1]. Two characteristic features of doctrinal development in Tang Buddhism merit emphasis:

First, Tang Buddhist thought and praxis were closely entangled with secular power and imperial legitimacy. During the dynasty, emperors actively patronized Buddhism and drew upon its rituals and deities to unite the populace and reinforce state authority [6]. In this sense, Buddhism functioned not only as a salvific religion but also as a political resource within the Tang order. Second, Tang Buddhism exhibits marked accommodation to native Chinese intellectual currents, including Confucian and Daoist thought [7]. Key tendencies include the elevation of certain Mahāyāna sutras—most notably the Saddharmapuṇḍarīka (Lotus Sutra) and the Avataṃsaka (Huayan) corpus—as hermeneutical centers; an intensified emphasis on tathāgatagarbha or Buddha-nature teachings; and the emergence of cosmologies in which the universal Buddha (e.g., Vairocana) functions as the ontological ground of all phenomena.

2.3. Institutional structures

The institutional framework of Tang Buddhism was primarily manifested in two domains: the system of monastic administration and the codification of disciplinary norms for the ordained community. The regulations governing Buddhist institutions—particularly those concerning monastic organization and clerical conduct—were placed under direct jurisdiction and strict supervision by the central government. This arrangement ensured the manageability of Buddhism within the political order and shaped the fundamental structure of monastic life from the Sui–Tang period onward.

Monastic administration in the Tang centered on the registration system (sengji), which had its origins in earlier Northern Dynasties but was further institutionalized under the Tang. This system required the official registration and periodic verification of all monks and nuns, thereby incorporating them into a census-like apparatus akin to the state’s household registration system (bianhu qimin). According to Tang legal codes, registers were renewed every three years, recording clerics’ names, places of origin, ordination dates, lineage affiliations, and scholastic attainments [8]. This institutional mechanism not only stabilized clerical identity but also enabled the government to monitor the size and movement of the sangha, preventing unchecked growth or unauthorized ordinations. As a result, Buddhist institutions—especially major monasteries—operated effectively as extensions of the state administrative apparatus while fulfilling their religious functions.

Ordination in the Tang entailed not only a religious commitment but also a legally regulated transformation of social status, subject to both state law and Buddhist disciplinary codes. State regulation of the monastic order was grounded in the legal framework of the “Lü, Ling, Ge, Shi” —a comprehensive system of statutes, ordinances, precedents, and administrative procedures. Among these, the Daoseng Ge, promulgated in the early Tang, set forth detailed administrative provisions concerning clerical conduct, including attire, diet, travel, and speech [9, 10]. In terms of Buddhist canonical discipline, Tang monastics primarily relied on the precepts contained in the Brahmajāla Sūtra (Fanwang jing) and the Dharmaguptaka Vinaya (Sifen lü) [10]. The former emphasizes that all sentient beings should follow a common set of rules, with a focus on self-discipline. The Dharmaguptaka Vinaya (Sifen lü) belongs to the Hīnayāna tradition and primarily focuses on regulating the conduct of monks.

3. Transmission pathways of Tang Buddhism

The spread of Tang Buddhism to Japan and the Korean Peninsula occurred through a network of interwoven channels, involving both Japanese and Korean monks travelling to Chinese religious centers and Chinese monks propagating Buddhism abroad. Although the specific chronological markers, actors, and institutional forms differ between Japan and Korea, the underlying modalities of transmission are largely comparable. In both regions, the primary mode can be identified: official or state-sponsored exchange (e.g., diplomatic missions, imperial requests for scriptures and teachers, and institutionalized study-abroad programs).

3.1. Transmission to Japan

The introduction of Buddhism to Japan can be productively analyzed through the dichotomy of “private” (popular) and “public” (official) transmission. “Private” transmission denotes diffusion via non-official, grassroots channels, while “public” transmission refers to state-sponsored or court-mediated exchanges [10]. Early instances of Buddhist introduction to Japan can be traced back to the reign of Emperor Kinmei, but contacts intensified during the Tang period as diplomatic and cultural exchanges deepened. Under the Tang-Japan exchange framework, transmission operated along two complementary lines. On the one hand, Japanese envoys and study monks (sent on official missions to China) systematically acquired canonical texts, monastic codes, liturgical procedures, and institutional models. On the other hand, transplanted monks and scholars from China established local monasteries, taught, and participated directly in the institutionalization of Buddhist practice in Japan [11].

A notable example is the arrival of monk Ganjin, who, after several failed attempts, successfully crossed to Japan at the request of Japanese clerics and led to profound influences in Japanese religion and culture [12]. Thus, through a combination of official missions, the sustained presence of transplanted clergy, and the importation of liturgical and textual repertoires, Tang Buddhism was rapidly transplanted and adapted within Japanese social and institutional contexts.

3.2. Transmission to Silla

Buddhism on the Korean Peninsula displays both continuity and phase-specific characteristics. It first entered Goguryeo and Baekje, and subsequently reached Silla [3]. Royal patronage in Silla played a crucial role in promoting doctrinal study and clerical formation [13]. Silla rulers dispatched monks to Tang China for scriptural study and ordination, while Chinese masters and texts were also welcomed in Silla, enabling local translation, teaching, and ritual activity.

Prominent Silla monks—such as Yuan Guang, Ci Zang, and Yuan Xiao—studied in Tang centers, acquired canonical knowledge and interpretive methods, and returned home to translate texts, lecture, and found monasteries. Tang monks also traveled to Silla to participate in translation projects and to preside over rites, forming part of a two-way flow [13]. Through these processes, Tang doctrinal and institutional models were assimilated and reconstituted within the specific political and social structures of Silla.

4. Reception and imitation of Tang Buddhism in Japan and Korea

In the process of transmission, both Japan and the Korean polities initially engaged primarily in reception and learning before entering phases of imitation and localized adaptation. Consequently, the early management of Buddhism was largely organized around the emulation of Tang models of sectarian affiliation, doctrinal orientation, and institutional arrangements. This section examines, with particular attention to the dimensions of sectarian formation, doctrinal appropriation, and institutional mimicry, how Japan and Korea received and imitated various aspects of Tang Buddhism.

4.1. Japan

Japan’s reception of Tang Buddhism involved a process of elite sponsorship and social institutionalization. From the Asuka period onward, support from the aristocracy exemplified by figures such as Prince Shōtoku, laid the foundation for Buddhism’s penetration into both court and society [10]. During the Nara period, Buddhist importation and formalization proceeded on a more systematic, state-sponsored basis [2]. Early reception encompassed three interconnected dimensions: sectarian organization, doctrinal uptake, and institutional imitation.

4.1.1. Reception and formation of sects

Sectarian formation in Nara-period Japan emerged as temple-centered study groups (commonly called “chō” or “shū,” i.e., communities or congregations) extended its influence beyond local institutions and developed supra-temple organizational networks. By the eighth century, especially in the Nara region (Nanto), a cluster of schools known as the “Six Nanto Sects” (Nan-to roku-shū) had become prominent: Sanron (Three Treatise), Jōjitsu (Tattvasiddhi), Hossō (Yogācāra/Faxiang), Kusha (Abhidharma/Kuśa), Kegon (Huayan), and Ritsu (Vinaya) [11]. These schools reflected the imprint of Tang Chinese Buddhist traditions. The arrival of transplanted clergy and eminent Tang masters, most notably Ganjin, further accelerated the institutionalization of vinaya study and sectarian structures in Japan.

4.1.2. Doctrinal appropriation and political instrumentalization

Nara-period monastic culture was broadly ecumenical, with monks typically studying multiple doctrines rather than adhering strictly to a single sectarian line [11]. This cross-school learning was partly a consequence of the political instrumentalization of Buddhism: the imperial court used Buddhist doctrine and ritual as resources useful to statecraft, and thus the formation of monastic curricula and institutions was substantially guided and constrained by imperial policy [14]. Tang-origin doctrines and textual repertoires (notably the Lotus, Avataṃsaka, and Brahmā’s Net traditions) were deployed in state-sponsored rituals and “protector-of-the-state” ceremonies.

The arrival of Ganjin represents a decisive moment in the institutionalization of Buddhist discipline in Japan. According to historical records, Ganjin brought forty-eight Buddhist scriptures to Japan and arranged for their copying and distribution among various temples. These texts effectively laid the theoretical foundation for the Japanese Ritsu school. In addition, Ganjin actively promoted Buddhism locally, with particular emphasis on the Tiantai and Esoteric traditions. He later joined other Japanese monks in forming a preaching group to expound the Brahmajāla Sūtra (Fanwang jing) [12].

Over subsequent centuries—particularly by the mid- to late-Heian period—other doctrinal currents, such as Pure Land thought, were reinterpreted and popularized within local socio-religious contexts [2].

4.1.3. Institutional imitation

Japan’s temple system and monastic administration were largely emulated on Tang precedents. Beginning in the Hakuhō period, the number of monks and nuns gradually increased. Following the Taika Reform of 645, Buddhism became an official ideological foundation of state governance, and the ruling elite promoted its influence through the construction of provincial temples (kokubun-ji) [11]. The Tōdai-ji temple, with its Great Vairocana (Rushana) Buddha statue, served as the central, national kokubun-ji. In addition, numerous provincial kokubun-ji followed Tang models of temple layout and administration [10]. At the macro level, Japan engaged in extensive temple construction; within the temples themselves, monks primarily devoted their efforts to the copying of Buddhist scriptures. In this process, Chinese thought was indirectly integrated into the Buddhist texts, meaning that what Japan absorbed at this time was not merely the original Buddhist scriptures, but also their Chinese exegetical interpretations [14].

Monastic training systems were also adapted from Tang models. The introduction of the “three teachers and seven witnesses” (sanshi shichishō) ordination procedure by Ganjin standardized monastic discipline in Japan, putting an end to the previously inconsistent and disorderly state of Buddhist regulations [12]. In addition, certain legal codes were promulgated to regulate the behavior of monks and nuns, such as the Sōni-rei (Ordinances for Monks and Nuns), which prescribed in detail the rules governing their clothing, food, housing, and daily conduct [10].

4.2. Silla

Tang–Silla relations were characterized by intensive political, military, and cultural interaction. Tang assistance materially supported Silla’s campaigns against Baekje and Goguryeo, fostering sustained exchanges in religion, learning, and administration. Against this backdrop, Silla proactively adopted and adapted Tang Buddhist traditions: Tang masters, texts, and ritual forms entered Silla through multiple conduits and became important resources for the construction of local Buddhist institutions and practices [14].

4.2.1. Introduction and formation of sects

Silla’s sectarian development was heavily influenced by Tang Buddhism, though local schools were not verbatim replicas. Prominent Silla sects included Esoteric (Mìzōng), Vinaya (Lǜzōng), Huayan (Huáyán zōng), Jungdo/Chungdo (Middle Way zong), and Cien (Ci’en zong) [14]. Leading Silla monks undertook study in Tang centers or were deeply influenced by Tang doctrinal currents: for example, monks associated with esoteric teaching, vinaya reform, and Huayan exegesis (e.g., Yuan Guang, Ci Zang, and Yuan Xiao) had direct study or contact with Tang monastic institutions. Even for those who did not personally travel to Tang, their thoughts and practices were often shaped by Tang intellectual trends that had already circulated regionally [13]. Thus, Silla monastic traditions during this period reflect both a continuity with Tang models and a process of selective indigenization.

4.2.2. Doctrinal development and local interpretation

Doctrinal development in Silla was driven principally by monks who had studied in Tang centers and then returned to teach and compose locally relevant expositions. For instance, Yuan Guang studied in Tang and, upon his return, produced works such as commentaries on tathāgatagarbha (Buddha-nature) literature—emphasizing doctrines that assert the presence of Buddha-nature in all beings—and thereby articulated a Silla-specific reception of such ideas. Similarly, Ci Zang studied major Mahāyāna texts in Tang, and on his return lectured extensively on treatises such as the Mahāprajñāpāramitā commentaries and the Bodhisattva Precepts, thereby disseminating vinaya and bodhisattva-path teachings within Silla [3].

In general, Silla doctrine shows patterns of selective appropriation: Tang canonical and exegetical materials were adopted, reinterpreted, and reworked in light of local concerns and practices.

4.2.3. Institutional adoption, reform, and practice

Silla’s monastic administration and disciplinary systems drew upon Tang Buddhist precedents but were adapted to local political structures. Ci Zang played a leading role in clerical governance and reform, holding the office of Daeguk-tong (“Great State Preceptor”) and the administrative model of appointing clerical officials to regulate the sangha was clearly inspired by Tang precedents [3]. Ci Zang’s regulatory measures—sometimes referred to in secondary literature as the “Ci Zang code” or related disciplinary enactments—helped standardize clerical conduct and institutional order [13]. These measures contributed to the emergence of a distinctly Silla vinaya tradition.

The establishment of ordination platforms and precept halls—such as the diamond-precept platform at Tongdo-sa—signaled the institutionalization of formal ordination practice in Silla. At the level of praxis, leading masters developed locally inflected practices: Yuan Guang promulgated methods of confession and reintegration (a form of repentance and reordination practice often summarized as “return-to-precepts and extinguishing of offences”), while other monastics promoted lay and monastic observances (e.g., the Eight Precept practices) that contributed to the wider social embedding of Buddhism [3]. Collectively, these institutional and practical developments illustrate how Silla adopted Tang models yet transformed them into forms suited to indigenous political and social contexts.

5. Innovations and localization of Buddhism in Japan and Silla

Buddhism in Japan and Silla evolves through processes of localization and innovation. These adjustments enabled Buddhism to resonate more closely with indigenous traditions, leading over time to forms of religious life that diverged in significant ways from Tang Buddhism.

5.1. Japan

In Japan, sectarian structures, doctrinal orientations, and institutional systems were no longer simple replications of Tang models; rather, they increasingly reflected a synthesis of imported traditions with local cultural elements.

5.1.1. Sectarian innovation and development

Two of the most prominent innovations in Japanese sectarian Buddhism were the establishment of the Tendai and Shingon schools. The Tendai school, founded by Saichō, was rooted in the Tiantai tradition of Tang China, with the Saddharmapuṇḍarīka (Lotus Sutra) as its central scripture. However, Japanese Tendai expanded its doctrinal scope by integrating the principles of “En” (Perfect Doctrine), “Mitsu” (Esoteric Buddhism), “Zen” (Meditative Practice), and “Kai” (Vinaya Discipline) [9]. This integration introduced divergences from the Chinese Tiantai tradition. For example, whereas Chinese Tiantai emphasized the cultivation of sentient beings, Japanese Tendai advanced the doctrine that even plants and trees possess the potential for Buddhahood [15]. Such innovations were in part influenced by esoteric teachings, which emphasized a more anthropomorphic and mystical conception of the dharmakāya and incorporated ritual practices such as mantras and prayers.

The Shingon school, founded by Kūkai, represented another major development. Drawing upon both Indian and Chinese esoteric traditions, Shingon emphasized the spiritual potency of mantras and advocated for mountain ascetic practices as a means to attain extraordinary powers [9]. These doctrinal emphases marked a notable departure from Tang models, signaling the emergence of distinctly Japanese forms of esoteric Buddhism. By the late Heian and Kamakura periods, further transformations gave rise to the so-called “Kamakura New Buddhism,” in which sects such as Pure Land, Zen, and Nichiren Buddhism consolidated, marking Japan’s transition toward autonomous religious traditions less dependent on Tang influence.

5.1.2. Doctrinal orientation

The localization of Buddhism in Japan also manifested in doctrinal orientation. First, Buddhism increasingly shifted from being an instrument of aristocratic rule to becoming a religion embraced by the broader populace. This transition reflected a movement away from an emphasis on Buddhism as a tool for worldly governance toward its role as a source of spiritual salvation for common believers. Second, although Buddhism maintained its longstanding entanglement with politics, its development in Japan took on a distinctly nationalistic dimension, characterized by strong “protect-the-nation” themes. Finally, the interaction between Buddhism and indigenous Shinto traditions gave rise to the doctrine of shinbutsu shūgō (the harmonization of kami and buddhas), representing a profound example of religious syncretism in Japan’s medieval period [9].

5.1.3. Institutional evolution

Institutional structures likewise underwent significant transformation. As Buddhism gradually became a religion of the populace and greater emphasis was placed on spiritual cultivation rather than monumental construction, the building of temples and statues began to receive less emphasis among lay believers. In the realm of monastic regulation, Emperor Kanmu sought to reform the Buddhist establishment during the Heian period. Faced with the growing political and social influence of the monastic community—sometimes with destabilizing effects—he implemented policies that curtailed the unchecked expansion of temples, restricted the ordination of monks and nuns, and reformed the system of clerical licensing [8]. These measures not only restrained the institutional power of the Buddhist establishment but also reshaped the contours of monastic life in ways distinct from Tang precedents.

5.2. Silla

Silla’s path of localization exhibited distinctive forms of institutional adaptation and doctrinal interpretation. These were manifested in the indigenization of sects, the tendency of doctrines toward state protection, and the integrative innovation of institutional structures.

5.2.1. The Silla-ization of Buddhist sects

Within Silla, Chinese Buddhist sects were not adopted in their entirety but rather selectively assimilated and reinterpreted in the local context. Doctrinal traditions such as Tiantai and Huayan continued to exert significant influence. Through processes of study, practice, and dissemination, Silla scholars and monks gradually shaped scholastic traditions that bore distinct local characteristics. For example, Silla Buddhist sects and their founders were deeply intertwined with Silla’s political structures and social hierarchy, as Buddhism during this period was closely integrated with the royal authority of the Silla state. Besides, different Buddhist schools, along with their founders and adherents—such as Ci Zang, Yuan Xiao, and Yi Xiang, as well as later traditions like Esoteric Buddhism and the Yogācāra school—were accompanied by indigenous Silla commentaries and interpretations of Buddhist scriptures [3].

5.2.2. The state-protecting orientation of doctrine and the pursuit of spiritual unity

The development of Buddhist doctrine in Silla was closely aligned with the interests of royal authority, in which Buddhist discourse served the purposes of state governance and social integration. Buddhism progressively evolved into a state-protecting religion, while simultaneously fostering the pursuit of spiritual unity and deeper localization. A representative example is the monk Ci Zang and his formulation of the theory of Silla as the “fundamental Buddha-land.”

5.2.3. The localization of institutions

Silla possessed its own political institutions, and when Buddhist institutions—such as temple administration and monastic practices—were introduced, they were integrated with existing local customs. One notable example is the Hwarangdo. As a state-sponsored system for recruiting and cultivating talent, the Hwarangdo also absorbed certain Buddhist elements into its ideology. In terms of monastic practice, disciplinary rules remained central for regulating the behavior of monks and nuns. Among these, Ci Zang established the Vinaya School of Silla (Silla gyeyul jong), which introduced new disciplinary regulations adapted to the local context [3].

6. Conclusion

Tang Buddhism exerted a profound influence on Japan and Silla in terms of sectarian development, doctrinal formation, and institutional structures. In the initial stage, both polities relied heavily on Buddhist scriptures and the instruction of Chinese monks, making their early forms of Buddhism closely aligned with Tang practices. Subsequent religious development, however, saw Buddhism gradually merge with local cultural traditions, resulting in transformations and divergences from its Tang origins. Transmission was facilitated through multi-layered, transnational exchanges, including official policies and diplomatic missions, as well as the personal journeys of monks who acted as cross-cultural mediators, circulating scriptures, doctrines, and institutions. Although Japan and Silla shared a similar starting point in adopting Tang Buddhism, their developmental trajectories diverged due to differences in indigenous cultural traditions, political needs, and social structures. Japanese Buddhism gradually diversified into multiple sects and formed complex ties with political authority, whereas Silla Buddhism emphasized state protection, combining Buddhist precepts with political institutions to sustain social and political order.

This study remains limited, focusing on the one-way influence of Tang Buddhism on Japan and Silla without adequately addressing the interactions between Japan and Silla themselves nor the potential reverse influence of these polities on Tang Buddhism. Future research would benefit from integrating archaeological evidence, epigraphic materials, and cross-linguistic scholarship to explore the multi-directionality and interactivity of Buddhist exchange networks in East Asia, thereby yielding a more comprehensive understanding of Buddhism’s role within the regional cultural system.