Kaibara Ekiken’s Syncretic Shinto–Confucian Philosophy

Abstract

During the Meiji period, the relationship between Confucianism and the indigenous Japanese religion of Shinto became more complex within the context of national culture and policy. The integration of Confucianism and Shinto became an important part of Japan’s modernization and ideological construction. However, this profound fusion did not emerge suddenly; as early as the Edo period, Confucianism and Shinto had already established a certain degree of interaction and influence. Therefore, this article attempts to outline an early example of the combination of Shinto and Confucianism (more specifically, Neo-Confucianism, which had a profound impact on modern and contemporary Japan) through the lens of the integrated thought of Shinto and Confucianism of the early Edo-period scholar, Kaibara Ekiken.

1. Introduction

It is generally believed in academic circles that during Japan’s medieval period, the fusion of Shinto and Buddhism became mainstream. Before the introduction of Buddhism, primitive Shinto in Japan mainly consisted of mythology and prayer rituals, lacking systematic doctrines and classical texts. It had not yet developed into a complete religious system. Therefore, strictly speaking, the initial fusion should refer to the blending of Shinto beliefs with Buddhism1, after which it can be called the fusion of Shinto and Buddhism. In other words, Buddhism significantly facilitated the systematic development of Japanese deity worship (Sueki 2006). From another perspective, the fact that Buddhism could guide Shinto suggests that Buddhist theory was more dominant than the Shinto theory of that time. However, as mentioned earlier, despite Buddhism’s powerful influence, indigenous Japanese belief in deities did not disappear. On the contrary, after absorbing Buddhist ideas, it became more defined and complete, eventually realizing the necessity of breaking free from its dependence on Buddhism to achieve independence. Over time, in China, the Neo-Confucianism that took a strict anti-Buddhist stance spread to Japan through Buddhist monks and became a new social ideology by the Edo period. This ideology fused with Japan’s indigenous Shinto, giving rise to a unique Confucian Shinto.

When Neo-Confucianism was first introduced in Japan, it was primarily disseminated through its association with Buddhism. Several factors may explain its eventual ability to gradually detach from its dependence on Japanese Buddhism (Niu 2007) and rise during the Edo period.

The first is the demand for new moral guidance. The prolonged social turmoil of the Warring States period, along with the integration of Buddhism and secular power, caused Buddhist institutions to become entangled in conflicts, with Buddhism sometimes acting as a destabilizing force, thus losing its authority as a moral power. In other words, Buddhism lost its credibility as a cohesive force in Japanese society. As Japan gradually emerged from the period of internal strife, intellectuals and rulers naturally sought a philosophy that could support peace and order. In this context, neo-Confucianism, emphasizing ethics and social order, became an ideal alternative (Bowring 2017). Additionally, the rise of Neo-Confucianism in China was partly a response to Chinese Buddhism, which laid the foundation for its spread to Japan.2

Second, there was a rise in literacy rates and the flourishing of the printing industry. The curriculum of medieval Japanese temples and samurai schools indicates that The Four Books, including The Great Learning and The Doctrine of the Mean, had already become an important part of education since the 13th century. However, Neo-Confucianism did not spread widely until the 17th century, when it became an independent tradition. This phenomenon is closely related to the significant socio-economic changes in Japanese society during the 16th and 17th centuries. Agricultural production, wealth accumulation, trade prosperity, the increase in literacy, and the development of the commercial publishing industry created favorable social conditions for the spread of Neo-Confucianism. As Kiri Paramore pointed out, “Notably, a nationally mobile and networked elite, high literacy among them, and a commercial publishing and distribution industry to service that literacy, seem to have been instrumental in facilitating the popularization of Neo-Confucianism in both China and Japan” (Paramore 2016, p. 46).

The third factor is the religious aspects of Neo-Confucianism. Research in the history of Japanese thought indicates a deep connection between the rise of Neo-Confucianism during the Tokugawa period (1603–1868) and popular religious practices. Unlike official religious institutions, this spontaneous grassroots religious practice focuses on individual moral cultivation, with its core characteristic being the theoretical construction of ethical order in the present world. Notably, the religious traits of Neo-Confucianism exhibited a dual historical dimension during its process of localization: on the one hand, it created structural tension with the bakuhan system through the cultivation of the internal moral subject, while it maintained compatibility with traditional social ethics on the practical level (Paramore 2016).

The gradual rise of criticism of the fusion between Shinto and Buddhism can be seen as the result of the gradual systematization and independence of indigenous Shinto (with some political factors involved). The rise of Confucianism, on the other hand, was the product of the interaction of multiple factors such as society, economy, and thought. The changes in both of these traditions reflect the complex transformation of Japanese society during the Tokugawa period, showcasing both the continuity and evolution of traditional religions and the development of philosophical systems that adapted to new societal needs. In this social context, independent Confucian scholars began to emerge with the departure from Buddhism and the acceptance of Confucianism. In rejecting Buddhism, these thinkers sought to establish a new fusion of Shinto and Confucianism. This was an intellectual effort and a strategic response to Buddhism’s past position in Japanese religion and life. However, the more specific question is: in what form did the fusion of Shinto and Confucianism take place, and what roles did each tradition play? How did this fusion lead to changes in Neo-Confucianism in Japan that differed from the Neo-Confucianism in China? To address these questions, it is necessary to delve into the thoughts of Confucian scholars in the early Edo period. Kaibara Ekiken’s thoughts on the fusion of Shinto and Confucianism are a good example of this timeline.

2. Deconstructing the Foundation of the Fusion of Shinto and Buddhism

From the perspective of the development of Tokugawa intellectual history, the fusion of Shinto and Confucianism is not an isolated case.3 In the era preceding Ekiken, as one of the early Confucian scholars in the Tokugawa period, Hayashi Razan (1583–1657) was heavily influenced by Neo-Confucianism. In works such as Honchō Jinja Kō, he proposed ideas such as Shinto is the Way of Principle and Shinto and the Way of Humanity are One. By critiquing the amalgamation of Shinto and Buddhism, Razan sought to construct a Shinto doctrine based on Confucianism, offering a philosophical foundation aligned with political goals. As we know, the early development of Shinto was deeply influenced by Buddhism, and, thus, the version of Shinto presented to Tokugawa thinkers naturally contained elements that had merged with Buddhist thought. However, due to Shinto’s inherent need for independence, as well as the anti-Buddhist tendencies within Zhu Xi 朱熹’s teachings, the integration of Shinto and Confucianism inevitably faced the task of rejecting Buddhism. Razan’s strict exclusion of Buddhism was a defining feature of his thought on the integration of Shinto and Confucianism, as he sought to establish a theory of Shinto free from Buddhist influence. This approach contrasts with that of his teacher, Fujiwara Seika (1561–1619), who, although introducing Confucian ideas into his explanation of Shinto, merely transformed the Confucian principles into the content of Shinto without strongly rejecting Buddhism. In this regard, Hayashi Razan’s fusion of Shinto and Confucianism can be seen as an advancement of Seika’s ideas, laying the foundation for Yamazaki Ansai’s further efforts to reconcile Shinto and Confucianism. Following Razan, Yamazaki Ansai (1619–1682) made his mark by integrating Zhu Xi’s teachings with Shinto to establish Suika Shinto. He emphasized the purity and orthodoxy of Shinto, incorporating Confucian values to create a religious system that balanced both traditions. Yamazaki’s approach was rooted in orthodox research into medieval Shinto traditions, drawing from Ise Shinto and Yoshida Shinto. Although Yamazaki Ansai’s thought is an extremely important example of the fusion of Confucianism and Shinto, his ideas have also been criticized. For instance, he is criticized for forcibly aligning Yin–Yang 陰陽 and the Five Elements 五行 (wuxing) with the Seven Generations of Heavenly Gods, among other things (Nagata 1992). The integration of Confucianism and Shinto is a continually deepening process. Wang Jiahua divides the fusion of early Edo-period Confucianism and Shinto thought into two types: one is the purification of Shinto mysticism through the rationalism of Zhu Xi’s teachings, and the other emphasizes the preservation of Shinto’s mysticism (J. Wang 1990). As a thinker from a later period, Kaibara Ekiken can be said to have followed the first path, deepening the fusion of Shinto and Confucianism in a secular direction, based on his firm rejection of Buddhism.

Kaibara Ekiken’s thought underwent three significant transformations. In his youth, he followed Buddhism under the influence of his mother and grandmother. However, he was later guided by his elder brother to abandon Buddhism and embrace Confucianism. Before the age of 36, he enjoyed reading the works of Lu Jiuyuan 陸九淵 (1139–1193) and Wang Yangming 王陽明 (1472–1529). However, after reading the Ming scholar Chen Jian 陳建’s Xuebu Tongbian 學蔀通辨, he turned to adopt Zhu Xi’s teachings. By age 39, Ekiken had firmly established his exclusive devotion to Zhu Xi’s philosophy. Between the ages of 50 and 60, he developed an unprecedented interest in Shinto, making three visits to Yoshikawa Koretaru (1616–1694), the founder of Yoshikawa Shinto, and meeting with scholars of Ise Shinto. He also personally wrote works related to Shinto, such as Shinju heikō aimotorazaru ron 神儒並行而不相悖論 and Jingikun 神祇訓, indicating that his interest in Japan’s indigenous Shinto remained consistent throughout his life. In Ekiken’s works, Shinju heikō aimotorazaru ron was completed when he was 62 and written in classical Chinese. In contrast, Jingikun was completed at 82 and written in Japanese vernacular. These two works represent the culmination of Ekiken’s discourse on integrating Shinto and Confucianism.

Considering Kaibara Ekiken’s personal life experience, it is evident that he spent many years studying Buddhism before turning to Zhu Xi studies at 36. After that, he rejected Buddhism for the rest of his life. Therefore, when Ekiken developed his concept of the unity of Shinto and Buddhism, his anti-Buddhist stance had already been fully formed. It can be said that his rejection of Buddhism was based on his own personal experiences, rather than a thoughtless adherence to Zhu Xi’s anti-Buddhist stance. Ekiken pointed out that Buddhism lacked ethical order and moral substance. At the same time, Japan’s indigenous Shinto possessed qualities conducive to moral instruction, rendering foreign doctrines unnecessary (Shinju heikō aimotorazaru p. 220). Ekiken aimed to repudiate the idea that Shinto and Buddhism are compatible and to challenge the notion of Buddhist influence on Shinto thought.

Ekiken, who saw Buddhism as a peripheral doctrine, acknowledged Shinto’s limited textual legacy yet argued that Shinto’s spirit was not devoid of meaning nor compatible with Buddhist doctrine. He condemned Buddhism’s adaptation as fraudulent (Shinju heikō aimotorazaru p. 220), aiming to dismantle the foundations of Shinto–Buddhist coexistence. While critically deconstructing the Buddhist philosophical system, Kaibara Ekiken systematically expounded the characteristics of Shinto thought through multiple lines of argument. First, he focused on constructing the uniqueness of Shinto: “Its doctrine is simple and not complex, unpretentious; simplicity makes it easy to understand, clarity makes it easy to follow; its essence is plain, not luxurious or cumbersome” (Shinju heikō aimotorazaru p. 220). This refinement of Shinto’s essential characteristics essentially serves as a deconstructive strategy against Buddhism’s sophisticated theoretical system. By returning to the primordial form of Shinto before the fusion with Buddhism, Ekiken attempted to establish the practical superiority of Shinto over Buddhism, namely its “easily known and easily practised” ethical operational characteristics.

It is worth noting that, in response to the long-standing criticism of the superficiality of Shinto theory, Ekiken responded with a functional interpretation: “Although its teachings seem simple and easy to understand, they contain profound truths. Because of this, cultivating one’s mind and character and fostering human relationships can stabilize the world, prevent disasters, and avert chaos” (Shinju heikō aimotorazaru p. 220). This dialectical argument, which seems simple but is profound in content, not only addressed doubts about the depth of Shinto theory but also elevated Shinto to the practical level of social governance. Through this comparative analysis, Ekiken repositioned the two philosophical systems in terms of their value; Buddhism’s speculative depth was reinterpreted as a potential disruptor of social order, while Shinto’s practical character was imbued with the real function of stabilizing political and religious order.

If we examine this ideological discourse within the specific historical context of early Edo Japan, its practical direction becomes even clearer. After the prolonged period of civil war, the Tokugawa regime, newly established, urgently needed to build an ideological system that suited its needs. Ekiken’s emphasis on the social integration function of Shinto doctrine resonated with the demands of the emerging regime. In short, by explaining the worldly, practice-oriented and ethical normative characteristics embedded in Shinto thought, Ekiken deconstructed the inherent connection between Shinto and Buddhism and, based on this, constructed a potential common foundation between Shinto and Confucianism through a secularizing direction.

The secularizing orientation of Ekiken’s thought is not limited to his fusion of Shinto and Confucianism. However, it is also reflected in the publication and writing of his works. Unlike Hayashi Razan and Yamazaki Ansai, Kaibara Ekiken did not establish an independent Shinto theory. His discourse on integrating Shinto and Confucianism is limited to just two works. Compared to the widespread dissemination of his Confucian works, such as Shinshiroku 慎思錄 and Taigiroku 大疑録, these two Shinto-related works did not receive sufficient attention during Ekiken’s lifetime. According to the researcher Tsujimoto Masashi, after completing Shinju heikō aimotorazaru ron, Ekiken primarily focused his efforts on promoting the publication of Daigaku-Shūsō 大学集疏, indicating that he may have been more inclined to disseminate his Confucian thought rather than focus on the societal spread of the integration of Shinto and Confucianism (Tsujimoto 2005). As for why he wrote Jingikun at 82, this may be related to his later habit of creating popular educational works. Emori Ichiro argues that Ekiken’s production of accessible literature in his later years reflected a shift in his mindset, as he gradually regarded the dissemination of practical knowledge for the common people as his mission (Emori 1990).

3. Using Confucianism to Support Shinto

Building on the rejection of Shinto–Buddhist syncretism, Ekiken sought to enhance Shinto’s principles by drawing on Confucian thought, emphasizing its ethical framework while maintaining Shinto’s autonomy from Buddhist doctrines.

“Since the medieval period in Japan, the ancient Chinese classics of the sages have been transmitted to our country. The teachings of these classics—focusing on rectifying the mind, cultivating oneself, and promoting moral virtues, such as benevolence—align fundamentally with our Shinto beliefs. The teachings of the sages are expansive, comprehensive, precise, and profound. They can complement and advance our religious doctrines, further elucidating the principles of Shinto. Therefore, those who study Shinto should also not neglect the study of the sage’s teachings. In essence, Shinto is a simple yet profound core teaching, and once the key is grasped, it can be encapsulated in a single phrase. Thus, although there is no need to seek external sources actively, if one can draw upon the support of Confucian teachings, the underlying principles will become clearer and more complete” (Kaibara 1985, p. 220).

In brief, Ekiken’s attitude is to use Confucianism as a means to support and enhance Shinto. Ekiken posits that Shinto, by its inherent nature, does not require external influences to validate its principles. Given this perspective, how does Confucianism—also an import—find a place within his framework?

Ekiken argues that Shinto embodies purity and sincerity (Kaibara 1985, p. 220). These attributes make Shinto particularly compatible with Japanese customs, accessible in understanding and practice. However, unlike interpreting Confucianism from the perspective of religious deities to establish a basis for connection,4 Ekiken built the relationship between the two on the level of daily human relations and ethics. Ekiken believed that the lack of doctrinal scripture in Shinto demonstrated that Japanese Shinto embodies a path of clarity, sincerity, simplicity, and uprightness—essentially, a way grounded in daily human interactions. He argued that this made it well suited to Japanese customs, easily understood and practiced.

Furthermore, he held that Chinese Confucian culture also embodies principles of rectifying the heart and cultivating social ethics, contrasting with the suppression of human nature in Buddhism. Therefore, he saw an inherent commonality between Confucian principles and Shinto doctrines, suggesting that there could be room for mutual explanation and inspiration. However, since Ekiken believed that Shinto’s doctrine was already complete and did not need external support, he regarded Confucianism as supplementary to Shinto, carrying forward the duty of safeguarding Shinto’s orthodoxy and purity. In Ekiken’s view, the teachings of sages from foreign lands could clarify the concepts within Shinto, helping people better grasp Shinto doctrines and teachings. “Thus, it is acceptable to say that Shinto can stand independently without relying on Confucianism, but it is unacceptable to say that Confucianism offers no support to Shinto” (Kaibara 1985, p. 220). Here, “relying” means borrowing or depending upon.

This arrangement seemingly diminishes Confucianism’s status by assigning it a secondary role. On a deeper level, however, Ekiken’s description of the characteristics of Shinto heavily borrowed vocabulary from Confucianism, such as “sincerity 誠”, “daily human relations 人倫日用”, and “don’t have to look for it from outside 不待求乎外”. His portrayal of Shinto relies on the Confucian lexicon and philosophy. Scholar Liu Ying argues that Ekiken’s ideal fusion positions Shinto as the “soul” and Confucianism as the “material substance”, forming an integrated entity in which both complement each other, suggesting a principal–agent relationship rather than strict subordination (Liu 2022).

Although Ekiken affirmed the value of Confucianism, this does not mean that Ekiken incorporated Confucian thought into Shinto without reservation. Ekiken advocated absorbing the teachings of the sages selectively, considering the differences between Japan and China. He believed that these teachings should not be adopted indiscriminately.

“As for the rules of ritual and law, it is natural that they vary according to the particularities of geography, climate, and historical context, adapting to different times and places. Even the systems of the ancient sage kings in China underwent continuous revision, adapting to changing circumstances. Surely, how could the institutions created by ancient sage kings of China be with flaws? Yet they also required modifications over time to align with changing conditions. Is this not due to the gradual evolution of customs from ancient to modern times in response to the needs of each era? Moreover, our land lies thousands of miles from China, and we have been separated from the ancient sages for several thousand years. Our customs differ profoundly, and our times are far removed. Today’s scholars, unmindful of the gradual changes in human society, indiscriminately adopt the rites and laws of China’s distant past as universally applicable to the present day in our land. This is akin to failing to understand the difference between boats and carts suited to water and land or the distinction between fur and cotton suitable for winter and summer. How can this be considered a wise adaptation to current circumstances?” (Kaibara 1985, p. 220).

It is important to note that Ekiken’s rationale for selecting aspects of the sages’ teachings was not about judging them as good or bad. On the contrary, he emphasized, “Surely, how could the institutions created by ancient sage kings of China be with flaws?” He revered the sage kings for establishing rituals, music, and education to benefit the people, indicating that Ekiken held the teachings of the sages in absolute esteem, different from Ansai’s veneration of virtuous figures, such as Zhu Xi. (In fact, Ekiken believed that one should maintain a spirit of skepticism toward Zhu Xi’s teachings and regarded Zhu Xi as a virtuous figure rather than a sage.)5 Ekiken proceeded to discuss, from temporal and spatial perspectives, why Japan should exercise discretion in adopting the ways of the sage. First, given that the sages are now distant in time, current customs have diverged from theirs, and each successive dynasty preserved and renewed the old systems, giving eternal vitality to the sages’ teachings. Second, regarding geography, Japan is thousands of miles away from China, with different customs and social conditions, so it is impossible to apply these teachings in a one-size-fits-all manner. Thus, Ekiken asserted that contemporary scholars should heed the changing human customs, weighing the advantages and disadvantages. He believed this was the proper way to approach the teachings of the sages.

Meanwhile, Ekiken highlighted the unfortunate obscurity of sage learning within Japanese society, attributing it to scholars’ failure to reasonably discern what is appropriate for different times and places, leading to a blind adoption of Confucian elements unsuitable for Japanese society and consequently to resentment toward Confucianism. “This is why common people harbor animosity toward Confucianism and why the benefits of sage learning remain obscure. As The Doctrine of the Mean says, ‘Living in the present yet reverting to the ways of antiquity will bring misfortune upon oneself’” (Kaibara 1985, p. 220). Finally, Ekiken articulated his core perspective: “Shinto and Confucianism can coexist harmoniously without contradicting each other” (Kaibara 1985, p. 220). The essential connection between Shinto and the Way of the Sage makes the Way of the Sage the core element in the fusion of Shinto and Confucianism. In other words, Ekiken believed that the Way of the Sage was the “bridge” for the fusion of Shinto and Confucianism. The later reinterpretation of the doctrine of the sages by movements such as Neo-Confucianism in China was, in fact, a response to the demands of the times, representing the expression of the Way of the Sage in different historical periods. For Japanese society, if the core principles of Shinto align with the Way of the Sage, then Confucian scholars should naturally use the later development of Neo-Confucianism to enrich the content of Japanese Shinto.

4. Shinto Is the Way of Heaven (Tendō)

To deeply examine the true implications of Kaibara Ekiken’s proposition that “Shinto is the Way of Heaven (Tendō)”, it is first necessary to analyze precisely the two core concepts: Shinto and the Way of Heaven (Tendō). The meaning of Shinto has already been discussed earlier. The idea of the “Way of Heaven (Tendō)” discussed here is not entirely equivalent to the “Way of Heaven (Tian Dao)” in the Chinese historical context—primarily due to the different understanding of Heaven. Tendō holds a distinctive meaning within Japan’s socio-cultural framework. Therefore, before discussing Ekken’s thoughts on Tendō, it is necessary to clarify to avoid conflating it with the concept of the “Tian Dao”, as understood by Confucian scholars of the Song Dynasty in China.

In the Japanese socio-cultural context, the term Tendō carries a profound psychological foundation, particularly shaped by the societal conditions of the Sengoku period. The prolonged era of warfare significantly influenced the formation and dissemination of Tendō as a concept. Among the warrior class, it was common to attribute individual destiny to Heaven. The outcomes of battles were often explained as the result of “the exhaustion of divine fortune” or “the protection of Tendō”. This cognitive pattern, which interpreted fate through Tendō, gradually developed into a belief system of Tendō identification, wherein Tendō was seen as having a decisive influence on human destiny. This notion reflects the samurai class’s understanding of fate and provided the cultural and psychological foundation for the widespread acceptance of Tendō thought in Japanese society. At the same time, Sengoku-period warriors held works of gunki monogatari (military chronicles), such as the Taiheiki, in high regard. The Taiheiki, which depicts the turmoil of Japan’s 14th-century Nanboku-chō period, profoundly influenced the warrior class with its embedded ideas of Tendō. These literary works not only deepened the warriors’ understanding of Tendō but also facilitated the broader dissemination and acceptance of Tendō thought across different levels of society (Shimazono et al. 2014).

As time progressed, the connotations of Tendō thought expanded, driven primarily by evolving political needs. In the early 17th century, the Taiheiki hyōban hiden rijinshō 太平記評判秘伝理尽鈔 (selected commentaries, secret transmissions, and underlying logic of the Taiheiki) proposed that feudal lords embody Heaven’s compassionate virtues and practice benevolent governance, warning that failure to do so would result in not being protected by Tendō (the Way of Heaven). This perspective emphasized the role of Tendō in legitimizing political authority, laying the groundwork for the later development of the “Taisei-ininron” (大政委任論, also called 天命委任論). According to this theory, Tendō conferred ruling authority upon the shogun, who in turn delegated power to the daimyōs, thereby establishing a framework for the legitimacy of governance. This doctrine, which addressed the ideological needs of political rule at the time, also reinforced and advanced the integration of Tendō thought into the political structures of early modern Japan. It was included in political texts, such as the Honsaroku 本佐録 and the Testament of Ieyasu 東照宮御遺訓 (Tōshōgū Goyikun). Furthermore, it appeared in publications such as the Nōgyō zensho 農業全書, an agricultural treatise aimed at the general populace. This demonstrated the transition of Tendō thought from an ideology confined to the ruling class to a widespread societal concept, extending its influence from the elite to ordinary citizens. However, regardless of the context, the idea of Tendō (the Way of Heaven) in Japan at this time differs from the meaning of the Tian Dao (the Way of Heaven) in Neo-Confucianism in China. In Japan, Tendō can be understood more narrowly as the Mandate of Heaven, referring to the control and influence of Heaven over an individual’s fate, which is more closely related to the idea of the response between Heaven and humanity in the Han Dynasty of China.

In the early Edo period, as the influence of Neo-Confucianism gradually expanded, various philosophical systems engaged in intense competition and exchange centred around the concept of the Tendō. This intellectual interaction refined and innovated theoretical frameworks and invigorated cultural and intellectual development. As Wakao Masaki observed, early modern Japan was characterized by the widespread recitation of the Taiheiki and the confluence of diverse belief systems and intellectual traditions, including Shinto, Confucianism, and Buddhism (Shimazono et al. 2014). The evolution of Tendō thought ran as a central thread throughout this period. Kaibara Ekiken was a key participant in this intellectual milieu. His proposition that “Shinto is the Way of Heaven (Tendō)” emerged as a significant product of this pluralistic cultural context, enriching and developing the concept of Tendō.

Ekiken states, “The way between heaven and earth is singular; therefore, human conduct is identical to Shinto, and Shinto is identical to the Way of Heaven; there are not two ways.” (Kaibara 1985, p. 220). In his Jingikun, Ekiken elaborates further: “Shinto is the Way of Heaven, which is also the Way of humanity. Our Japan, referred to as a divine nation, is situated in the eastern sea of the world, filled with the essence of divinity. Hence, its people often perform acts of virtue akin to those of divine beings without the brutishness found among outsiders, distinguishing themselves from animals. In truth, Japan does not monopolize Shinto; the Way of the Sages from ancient China, such as Yao and Shun and Confucius, are also Shinto. Our ancient texts, such as the Kojiki 古事記 and Nihon Shoki 日本書紀, record the history of ancient times. However, to understand the principles of Shinto in our country, we must seek the teachings of the sages from the Way of the Sages from ancient China. The Way of Shinto in Japan is an unspoken doctrine without written texts; the sacred scriptures of ancient China are precisely the scriptures of Shinto. Between heaven and earth, there is but one Way.” (Kaibara 1911, p. 650).

It is important to note that Ekiken’s writings primarily address the ordinary people of Japan; hence, his expressions are more accessible and straightforward. Ekiken posits that Japan, located in the east and rich in the divine essence, reveres deities and believes that all spirits embody the essence of heaven and earth, leading people to emulate the sacred virtues. This again indicates that Ekiken aimed to discuss Shinto’s characteristics based on its original form’s traits. Furthermore, Ekiken emphasizes that although Japan has some historical texts documenting ancient events, understanding the principles of Shinto still requires reliance on the classical texts left by the sages of China. He asserts that the ways of Shinto, humanity, and heaven are all aligned, which implies that Japan can draw on the teachings of the Chinese sages to understand the doctrines of Shinto. This also imbues the Way of Heaven with a dual significance, encompassing religious belief and Confucian moral principles.

While Ekiken refers to Japan as a divine nation, “divine” primarily highlights Japan’s polytheistic beliefs. Wang Jie believes that the core of Ekiken’s fusion of Shinto and Confucianism is the Way of Heaven(Tendō). His interpretation of the Way of Heaven(Tendō) is fundamentally different from Zhu Xi’s concept of the Way of Heaven(Tian Dao), which is centred on the principle of li (principle). Through an analysis of Ekiken’s works, including Shinshibetsuroku 慎思別録, Wang argues that Ekiken’s conception of the Way of Heaven displays numerous characteristics of a personal deity imbued with a strong sense of rewarding good and punishing evil. Thus, Ekiken’s thoughts on the Way of Heaven are deeply intertwined with native Shinto beliefs (J. Wang 2015). Since Ekiken equates Shinto with the natural manifestation of the Way of Heaven, the personal characteristics found in some beliefs related to deities within Shinto subtly influence Ekiken’s views on the nature of the Way of Heaven. Ekiken points out the need to respect the warnings of heaven (Kaibara 1927a). In his later work, Yamato zokukun 大和俗訓, he asserts, “Knowing the mandates of heaven, one should follow them” (Kaibara 1927b). Ekiken also emphasizes that humans should feel grateful towards heaven and earth. The personified concept of heaven within Ekiken’s idea of the Way of Heaven conveys a rich array of meanings. The heavenly authority can reward good and punish evil on a political level. At the same time, individual fortunes and misfortunes are tied to heavenly mandates. In this framework, rulers act as executors of the heavenly will, while the Way of Heaven governs ordinary citizens. It becomes apparent that Ekiken elevates the Way of Heaven to the status of religious belief.

However, in Ekiken’s view, there is no strong tendency to elevate the principles of Shinto above those of the Chinese sages. Instead, he emphasizes the equality and consistency of principles, arguing that both the Way of the Sage and Shinto are centred on human relationships and daily life, focusing on moral education and practical morality. Thus, these two paths possess the potential for mutual supplementation, with anything else considered non-humanistic. Based on this inclination and understanding, Ekiken exhibits a strong cultural identification with the Way of the Sage. However, his ultimate aim for this cultural identification is to cultivate Japan’s culture, reflecting a robust sense of national pride rather than a psychological dependency on another culture.6

By examining Ekiken’s other works and academic interests, it becomes clear that his concept of the Way of Heaven (Tendō) has Confucian and religious elements and includes ethical and natural tendencies. These ethical and natural tendencies can also be seen as a continuation and further development of Zhu Xi’s teachings. On the ethical level, Ekiken inherited the concept of “li” (principle) in Zhu Xi’s philosophy and believed that the Way of Heaven gives birth to all things and that human ethics derives from the virtue of Heaven and Earth. Therefore, he emphasized that people should practice following the Way of Heaven (Tendō). This forms a coherent route from cosmology to human nature theory and finally to practical application, inheriting the ethical characteristics of Zhu Xi’s philosophy. On the natural level, Ekiken often highlighted the joy of exploring the natural principles of Heaven and Earth in his scholarly pursuits. He gave humans an active role in engaging with the Way of Heaven (Tendō) rather than being passive recipients of it. He is generally seen as developing the natural path within Zhu Xi’s philosophy.

As a result, Ekiken’s view of the Way of Heaven presents an impression of blending multiple elements. His concept of the Way of Heaven not only follows the widely popular view of Heaven in Japan since the Warring States period, such as the personification of Heaven and the idea that Heaven rewards good and punishes evil, but it also reflects the influence of Dong Zhongshu董仲舒’s ideas on the response between Heaven and humanity (Ekiken also quoted Dong Zhongshu in a letter to Kuroda). He combined the virtues of rulers with divine warnings. Additionally, he imbued Tendō with the characteristics of Neo-Confucianism. Ultimately, these ideas converged into the core concept of Tendō, reflecting the coexistence of religious and Confucian traits.

5. The Justification for the Unity of Shinto and Confucianism

The core of Ekiken’s idea of the unity of Shinto and Confucianism lies in emphasizing that Shinto is the Way of Heaven (Tendō), and the Way of Heaven is the Way of Humanity. Through the central concept of Tendō, he links Shinto with the Way of Humanity. As previously analyzed, Ekiken’s concept of the Way of Heaven is rich in meaning, reflecting religious elements and ethical concerns related to interpersonal relationships while also embodying the rational dimension emphasized in Zhu Xi’s philosophy. The interplay of these aspects merits a deeper analysis, both in terms of content and theoretical validity.

Specifically, attributing a religious hue to the unity of Shinto and Confucianism is an inevitable part of integrating Shinto with Confucianism. However, it is important to note that the religious aspect in Ekiken’s theory is not prominent, which sharply contrasts with the suika shinto established by Yamazaki Ansai, another adherent of Zhu Xi’s teachings. Ekiken’s discussion of the unity of Shinto and Confucianism pays relatively little attention to the theoretical construction of Shinto’s religious colour; instead, his main effort is to transform Shinto’s spiritual core using the principles of Confucian ethics. Additionally, due to Ekiken’s scholarly inclinations and the rationalist tendencies within Zhu Xi’s thought, he strongly emphasizes “practical” scholarship. In this regard, we can say that Shinto serves as the foundation and background. At the same time, Confucianism embodies the essence of Ekiken’s thought. The rationalist spirit from Zhu Xi’s teachings is the driving force that connects the three.

On this point, those familiar with Zhu Xi’s teachings may raise questions. Zhu Xi advocated the investigation of things and the pursuit of principles 格物窮理 (Gewu qiongli), but the concept of principles 理 (li) in his thought primarily leans toward human ethical principles and appears to have little connection with natural rationality. First, consider the term “investigation of things and the pursuit of principles”. Cheng Yi程頤 interprets 格 as to investigate; 窮 (qiong) as to exhaust; 物 (wu) as things; and 理 (li) as principles, suggesting that 格物窮理 means to exhaust the principles of things (Cheng and Cheng 1981). In The Great Learning, 格物 is presented as the primary approach to knowledge, leading to the assertion that “between rulers and subjects, fathers and sons, all are principles” (Cheng and Cheng 1981). Cheng Yi thus believes that scholars should exhaust the universally applicable principles, encompassing the principles of specific things (natural sciences) and social ethics. Given that the scope of principles is so vast, how should scholars understand it? Cheng Yi pointed out that everything has its principle, and the methods for pursuing principles are varied; scholars may comprehend ethical principles through reading, discussing historical rights, and wrongs, or realize principles in everyday interactions (Zhu and Lü 2008). Here, two questions arise. First, do we need to exhaust all things to understand all principles? Cheng Yi elaborates on this: “Even Yan Hui 顔回 did not dare to say this” (Zhu and Lü 2008). He believes even someone as gifted and studious as Yan Hui would not be able to exhaust all things; how much less so for ordinary people? Cheng Yi demonstrates a process from quantitative change to qualitative change, suggesting that through continuous investigation, one can accumulate knowledge to achieve a state of understanding all principles.

The second question is whether the principles in the natural world are as important as the principles in the ethical world. This involves a question of priorities. Cheng Yi believes that “The pursuit of knowledge lies in the investigation of things; understanding the principles of things is not as critical as self-reflection, and one’s gains are especially pertinent” (Cheng and Cheng 2000). This statement can be interpreted in two ways. First, scholars should regard self-examination as the most important method; second, they must reflect on whether their concepts conform to ethical principles. Understanding moral principles is of greater importance to Cheng Yi, reflecting the Confucian traditional view that a gentleman should prioritize self-cultivation. It is worth noting that natural principles also fall within the realm of the pursuit of principles. However, the ultimate focus remains on oneself rather than the principles of specific things.

Using Cheng Yi’s thoughts, Zhu Xi further comments on the “investigation of things”. Specifically, Zhu Xi states: “格 means to reach; 物 means to focus on matters; 窮理 is to seek the utmost without missing anything” (Zhu 2011). In other words, Zhu Xi believes that acquiring knowledge involves “directly addressing matters to exhaust their principles”. He posits that “To use one’s existing knowledge to further explore and thoroughly understand the principles of all things” (Zhu 2011). Once one achieves this understanding, one attains the highest knowledge. So, what are the characteristics of Zhu Xi’s method of investigating things? Firstly, regarding the scope of the investigation, Zhu Xi provides a clearer expression of Cheng Yi’s thoughts, asserting that all things have principles, and failing to investigate one will result in missing out on one principle. Given that all things possess different principles, are they equal? Is there no order? Zhu Xi states, “In investigating, one must also consider urgency and priority” (Zhu 2018). Scholars should focus on “understanding heavenly principles, clarifying human ethics, discussing sacred words, and grasping worldly affairs” rather than being preoccupied with trivial matters, such as grass, trees, tiles, and stones.

In other words, while the distinction between knowledge of virtue and knowledge through experience began with Zhang Zai 張載, these distinctions never departed from Confucianism’s emphasis on morality. The inherent moral inclination was not altered but rather strengthened through the theoretical refinement and development by scholars of the Song and Ming periods. This characteristic is especially evident in Zhu Xi’s teachings. Although Zhu Xi rarely mentions knowledge of virtue, by linking the object of investigation with experiential knowledge, he ultimately defined the goal of investigation as the attainment of moral knowledge. This means that through understanding the principles of external things, one can attain the metaphysical heavenly principles, which relate more closely to human ethical standards.

From the perspective of theoretical validity, if Ekiken had become a strict follower of Zhu Xi, like Yamazaki Ansai, and did not propose his revisions and critiques of the theory, Zhu Xi’s teachings in Japan would similarly have leaned towards strict moral tension, losing the potential for dissemination among the general populace. This is because the goal of self-cultivation in Zhu Xi’s teachings is less about depicting human nature but rather about portraying a vision of rational personality. There is always a gap between this vision and the individual’s true psychology, necessitating the subject’s continuous self-cultivation to approach this psychological experience. However, unlike traditional Chinese society, where those who genuinely studied and practised Zhu Xi’s theories on self-cultivation were primarily educated elites or members of the scholar-official class, the primary responsibility of early Edo-period Zhu Xi scholars, especially those from the Kyoto school, was to integrate Confucianism into the daily lives of the populace, implementing this theory centred on self-cultivation into practice. This transformation from theory to a mode of living for people is not a direct and simple leap; rather, it involves a certain distance that needs to be bridged. This bridging process requires both individual acceptance and practice of the theory and the theory’s necessary adjustments and transformations. Ekiken’s efforts are precisely aimed at bridging this gap.

To begin with, regarding the nature of Confucian moral psychological experiential, due to the absolute reverence for the sage’s character, this experiential imposes a remarkably high moral standard on individuals, demanding absolute goodness in their moral motivations. As Wang Yangming noted, “What I emphasize with the unity of knowledge and action is that when a thought arises, it is already an action. If a thought that is not good comes to mind, one must eliminate it immediately; do not allow negative thoughts to take root in the heart” (R. Chen 2017). This statement highlights the essence of Confucian moral psychological experiential. Instead of relying on external guidelines or laws to judge and regulate behaviour, Neo-Confucianism requires that goodness be present when a thought arises. Even virtuous actions are rendered meaningless if one’s thoughts are not good. This demand represents a higher moral aspiration, aligning with the true essence of virtue, akin to what Kant called the “moral law within me”. However, even in the era of the Song Confucians, those striving to follow the teachings of the sages were primarily members of the literati or elite scholar-official class. Ordinary people are the only group that receives the educational system of rites and music developed by the saints. To some extent, the assertion that “everyone can become a sage like Yao 堯 or Shun 舜” is a rather optimistic proposition. In other words, what should be does not necessarily equate to what is practically achievable; theoretical possibilities do not always translate into practical realities. The sage’s path, which claims that “even foolish men and women can reach the realm of the sage” (R. Chen 2017), assumes an innate goodness in humanity. In practice, individuals need to reflect daily on the morality of their thoughts and actions. Each individual is both the doer and the doe of moral psychological experiential. However, the sage’s perfection often highlights one’s imperfections. While the “realm of the sage” can inspire individuals to strive toward that ideal standard, in practice, it usually leads to a tendency for continual self-correction or self-reproach. In the late Ming dynasty, many Yangming scholars produced numerous self-reflection writings, with some even claiming that they had no virtues at all, only faults, stating that “they are filled with sins” (from Complete Works of Liu Zongzhou, Human Profiles) or that “if one is not a sage, they are merely a deluded beast” (Q. Chen 1979 ). This kind of strict moralism can turn what is fundamentally a positive psychological experience into one of self-denial. Therefore, in practical terms, if scholars strictly hold the “sage’s ideal” as the standard for psychological experiential, the theory risks becoming a treasure only for a select few. The pursuit of sagehood has historically been an aspiration for a minority. At the same time, it may suffice to nurture more good thoughts and fewer bad ones for the broader public. Finding a “middle ground” between the sage and the ordinary person is essential for making Confucian theories of moral psychological experiential both relevant and moderate in contemporary society.

Moreover, the various concepts promoted by Confucian scholars—such as “Doctrine of the Mean 中庸”, “Benevolence 仁”, and “Conscience 良知”—fail to accurately capture the essence of the moral psychological experiential. Instead, they merely indicate certain representations of this experience. This limitation arises from the Confucian tendency toward a form of understanding characterized by “wu 悟”, which suggests that verbal expression ultimately falls short of the inner realization. This kind of understanding is subtle, profound, and difficult to articulate. For instance, Lu Jiuyuan remarked, in response to a question from Bo Min 伯敏 about human emotions and nature: “There is no need to speak; that which can be articulated is not true understanding” (from the Collected Works of Lu Jiuyuan). Similarly, Wang Yangming believed that conscience does not need to be sought through external affairs but can be realized by uncovering one’s true heart. However, even Wang’s insights into conscience came only after decades of trials and tribulations, culminating in a sudden awakening to his true self. Without concrete adherence to or practice in daily life, how can one truly comprehend this knowledge of the conscience? In the earlier critiques of Lu Jiuyuan’s ideas, Zhu Xi expressed concern that this direct method of discovering one’s true heart, while rooted in the essence of Confucian thought, could easily lead individuals astray. In a letter to Wang, his disciple Nie Bao 聶豹 wrote, “I have reflected on my inner self, attempting to seek knowledge of the conscience from within. Although the mind’s function is subtle and profound, it often seems to feel that there is no means by which it can be specifically relied upon. Recently, however, I have found a way to experiential this knowledge of the conscience through my duties of filial piety to my parents and respect for my elders” (Nie 1997, p.386). Nie Bao found it challenging to grasp the concept of conscience by directly reflecting on his heart. Instead, he began his journey from the acts of filial piety and brotherly love in daily life, which provided him with a practical path to follow.

At the same time, when theory is applied to practice, it often reveals layers of complexity and discrepancies with the original theoretical concepts. Most individuals do not base their choices on the completeness or profundity of a theoretical system but rather on its practicality. As Wang Fansen noted, “Throughout Chinese history, any thought that made a significant impact in daily life has likely undergone a process of simplification—this includes an omnipresent principle of ‘frugality,’ which breaks down relatively complex and profound ideas into simpler, more accessible forms. Over time, these may evolve into a few concepts or slogans, continuously being popularized or rewritten (including both concretization and metaphorization)” (F. Wang 2018). For individuals still imperfect in their practice or experience, pursuing an excessively lofty spiritual realm too early may not be beneficial. In reality, abstract and elevated moral psychological ideals, such as “harmony between the heaven and human”, cannot be said to have no connection to the vast majority of ordinary social behaviours; they may be quite distant from them. Therefore, in order to popularize Confucian ideals among the people, the focus should not solely be on inner experiential as the primary guiding principle. Instead, there should be a degree of externalization and practical application of the theory. Ekiken’s efforts, such as skillfully transforming Confucian theories into the spiritual core of Shinto and composing accessible instructional texts, all aim to deepen the integration of Confucianism into popular culture and to facilitate the reform of customs and practices in Japanese society through Confucian thought. Thus, while Ekiken may appear broad in theory but lacking in depth, and even though he later devoted himself to writing instructional texts, he nonetheless left a significant mark on history. His instructional writings continue to be recited and read to this day.

6. Discussion and Conclusions

Kaibara Ekiken’s attempt to integrate Shinto with Confucianism must be examined within the broader context of his intellectual project, particularly his revisionist stance toward Zhuxi studies. In Studies in Intellectual History of Tokugawa Japan, Maruyama Masao constructs a historiographical framework centred on the Sorai school, positioning Ekiken as a critic of Zhu Xi’s thought. According to Maruyama’s analysis (Maruyama 2014, p. 62), “As a result, the anti-Ghu Hsi tendencies that emerged in his Jigoshu [Essays for my own amusement] in 1712 and increased in intensity in his Shinshiroku [Record of Prudent Reflections] in 1714 finally exploded in Daigiroku”. Maruyama’s study, grounded in the internal logic of Japanese intellectual history, outlines a clear trajectory of thought development that situates Ekiken within the complex scholarly currents of the Tokugawa period. It brings to light his interaction with the Ancient Learning school and, in particular, underscores his revisions to Zhu Xi’s metaphysical framework of li (principle) and qi (vital force). However, scholarly debate persists as to whether Ekiken’s thought constitutes a fundamental rejection of Zhuxi studies. Lin (2016) argues that Japanese scholars’ critiques of Zhu Xi’s conception of the li–qi relationship do not necessarily amount to a wholesale negation of Zhuxi studies. Tsujimoto (2016), examining Ekiken’s reading list, contends that his thought should be situated within the broader peripheral context of contemporary developments in Chinese Zhuxi studies. This position is supported by compelling historical evidence that the founding of the Tokugawa shogunate coincided with the late Ming period in China, during which Zhuxi studies had already begun to exhibit a marked tendency toward the transformation from li-centred to qi-centred interpretations. Significantly, Ekiken frequently cites and affirms the views of Luo Qinshun, a prominent Ming-dynasty advocate of a qi-monist position. Thus, when viewed within the broader trajectory of Zhuxi studies across East Asia, Ekiken’s divergences from Zhu Xi’s original formulations appear not as acts of doctrinal rupture but rather as part of a natural evolution of scholarship in line with the intellectual currents of his time.

It is important to emphasize that such intellectual revisions are closely tied to both the scholar’s socio-historical context and individual disposition. As a thinker grounded in practicality and rational inquiry, Ekiken’s reconfiguration of Zhu Xi’s philosophy exhibits a distinct orientation toward real-world concerns. Compared with Ming dynasty thinkers, his theoretical adjustments reflect not only a profound engagement with the realities of Japanese society but also a critical appropriation of traditional intellectual resources. This dual orientation becomes especially salient in his effort to synthesize Shinto and Confucianism, exemplifying the creative adaptation undertaken by early Tokugawa scholars in their reception of foreign thought.

Compared to his more renowned Confucian works, Ekiken’s integration of Shinto and Confucianism did not achieve widespread influence or dissemination during his lifetime. Does this suggest that the early Edo period was solely an era of Confucianism? Herman Ooms, in Tokugawa Ideology Early Constructs, 1570–1680, proposes that the early Tokugawa period’s ideology was a composite form encompassing Zhu Xi studies, Shinto, Buddhism, and the Way of Heaven, characterized by the sacralization of these thoughts. Yamazaki Ansai, by integrating Zhu Xi’s teachings with Shinto, established Suika Shinto, which is regarded as a more complete stage of this ideology (Ooms 1985). Furthermore, Kurozumi Makoto, in Early Modern Japanese Society and Confucianism, emphasizes that the defining feature of Japanese social thought during the Tokugawa period was the religious syncretism inherent in it (Kurozumi 2003). This ideological syncretism shares a common characteristic: “secularization”. Early Edo-period thinkers broadly exhibited this quality.

In Ekiken’s thought system, he promoted the popularization of Confucianism through the “Unity of Shinto and Confucianism” approach, grounding it in the Cheng-Zhu school while not rejecting practical matters of daily life. This represents a distinctive path of Confucian development in Japan. As Cheng-Zhu thought was accepted and practised in Japan, Ekiken emphasized the ethical dimensions of DaoXue 道学7, particularly its application in everyday life, enabling Confucian ideals to penetrate deeply into Japanese society and take root in concrete cultural practices. This development enriched the content of DaoXue and facilitated the mutual integration of Confucianism and Shinto.

Beyond Ekiken’s approach, the interaction between Shinto and Confucianism was even more multifaceted. For instance, unlike Ekiken, who was devoted to Song Confucians, Ogyū Sorai fundamentally questioned the “cultivation of mind and nature” promoted by the Song Confucians, viewing it as tainted by personal bias and lacking the absolute purity of the “Way of the Sages”. Sorai argued that only the teachings of Confucius and earlier sages embodied the unadulterated way, thereby liberating Dao’s principles from individual ethics and emphasizing the superiority of institutional frameworks to establish stable, objective order. Masao Maruyama suggests that Sorai sought to diminish the subjective influence of personal virtue through the objectification of political institutions (Maruyama 2000).

A comparison of Ekiken’s and Sorai’s perspectives reveals different pathways for Confucianism’s transmission and localization in Japan. Ekiken, through the unity of Shinto and Confucianism, connected Confucian ethics with the ruler’s virtue via the concepts of cosmic resonance and reward for good and punishment for evil, highlighting the influence of the benevolence inherent in Heaven’s Way on governance, thus emphasizing the Cheng-Zhu school’s focus on individual morality. Sorai believed that only the system of ritual and institutions recorded from the time of Yao and Shun could be considered objective. In contrast, the ideas of the Song Confucians were deeply influenced by personal temperament. Their interpretation of the teachings of the sages was primarily aimed at countering Buddhism and Daoism. This approach placed their doctrines in a relative, debatable position, thus losing their absoluteness. As a result, Sorai argued that only the teachings of Confucius and those before him could be called the “teaching of the sages”. He excluded Mencius and Xunzi from this category because, by their time, the Dao had already lost its absolute, dominating position and was often engaged in debates with other philosophies or used to address contemporary issues. Therefore, in Sorai’s system, the virtues discussed by the Song Confucians were no longer emphasized. Instead, only the specific “virtue” passed down through the ancient system of ritual and institutions could serve as the model for practising the way of the sages. Ekiken, therefore, represented a life-oriented, popularized approach to Confucianism. At the same time, Sorai sought to shift Confucianism toward pursuing institutional order. These diverse and distinctive exchanges illustrate the different developmental paths of Confucianism within foreign cultures and also reflect the unique contributions arising from the interaction and integration of Confucianism and Shinto in Japan.

In general, Kaibara Ekiken’s thought of harmony between Shinto and Confucianism is not only a strategy to respond to the influence of Buddhism but also an attempt to solidify the core of Shinto culture through Confucianism. Subjectively, it aims to preserve the purity of the indigenous religion, positing that Confucianism merely plays a supportive role. However, the principles he emphasizes within Shinto already carry a distinct Confucian character. Therefore, rather than viewing the relationship between Shinto and Confucianism as that of Shinto being the master and Confucianism being the guest, it is more appropriate to say that the core content of Confucianism is used as a tool for Shinto. This research example demonstrates the complex situation faced by Confucianism, as a foreign culture, in modern and contemporary Japanese history, as well as its powerful inclusiveness. At the same time, it also shows us the new developments of Zhu Xi’s philosophy in early Edo-period Japan. These new meanings also hint at the separation between Japanese Neo-Confucianism and Confucianism on the mainland, raising the question of why such differences emerged.

The reasons why early Edo-period scholars of Zhu Xi studies diverged from the path of Chinese Confucianism may lie in the following factors. The first difference lies in the composition of the scholar-officials in China and the samurai class in Japan. In China during the Song and Ming periods, the mainstream group of Confucian scholars comprised scholar-officials who aspired to or succeeded in obtaining official positions through studying Confucian classics (including those who failed the imperial exams). They held varying degrees of power in the government. Studying Confucian classics from a young age and delving into Confucian teachings was quite natural for them. In contrast, in early Edo Japan, the samurai class, which had emerged after the end of the civil wars, did not rely on studying Confucian classics to secure official positions as the Chinese scholar-officials did. In other words, the samurai class did not see the study of Confucian thought as essential to their roles. Their survey of Confucianism did not directly determine their official positions or status. Therefore, rulers and samurai in Japan used Confucianism more pragmatically, considering practical applications. As James McMullen observes in Confucian Perspectives on Tokugawa Japan: “Though over time Tokugawa society came to accept many ideals and practices from Confucianism, its leaders were no more attracted by a meritocratic examination system as entry to administrative office than were those in ancient Japan. Once more, hereditary oligarchy became the dominant form of political control” (McMullen 2021). From the perspective of the samurai class, Watanabe Hiroshi offers a psychological perspective. With the cessation of warfare, the samurai class faced diminished clarity in their societal contributions. They naturally sought to justify their existence, often through appeals to “public significance” or “transcendence”. In other words, they needed Confucianism to provide meaning to their lives in a time of peace. As Watanabe explains, in the Pax Tokugawa era, samurai had to demonstrate their value to rulers, the public, and themselves. They could either appeal to the realization of their latent functions (an inherently tenuous claim) or rely on a transcendent dao to justify their role as a class (Watanabe 2020). The Confucian ideals of loyalty 忠 (Zhong) and righteousness 義 (Yi) met the needs of the samurai, making Confucian values acceptable and promotable within the samurai class. These differing attitudes and needs naturally shaped their selective adoption and transformation of Confucianism. In brief, “The development of the samurai code during the Tokugawa period can be summarized as follows: As the historical changes in the form of samurai society took place, everyday behaviours gradually overshadowed actions in extraordinary circumstances, and the initial sense of camaraderie evolved into a generalized ethical norm for the expanding feudal vassal system” (Maruyama 2021).

Second, there is tension between Zhuxi studies and the Tokugawa government. Neo-Confucianism became the official orthodoxy in China, closely tied to imperial politics and theoretically maintaining the dominance of “moral rationality”. However, in Japan, while Neo-Confucianism was also adopted by the government during the Edo period, its social function focused more on individual moral cultivation and providing an ethical framework for the samurai class. Although Japanese Confucian scholars such as Hayashi Razan and Yamazaki Ansai drew on Zhu Xi studies, their understanding of Confucianism leaned toward ethical practice rather than abstract metaphysical discussions. One possible reason for this divergence is the tension between Confucianism and the feudal political system. The practice of Confucianism under the Tokugawa shogunate faced significant political tension, particularly the contradiction between Confucian moral ideals (such as the concept of the virtuous ruler and the theory of the Mandate of Heaven) and the hereditary system of feudal society. Many Japanese Confucian scholars sought to reconcile this contradiction. For instance, Yamazaki Ansai, while affirming Confucian notions of orthodoxy, rejected doctrines advocating the replacement of immoral rulers to align with the Tokugawa shogunate’s political reality. This indicates that Japanese Confucian scholars often had to find compromises between ideals and reality, even adjusting core Confucian doctrines to ensure their applicability in feudal Japan’s social and political context.

Third, the development of Japanese Confucianism integrated various intellectual elements. This has become a widely accepted consensus in current scholarship. Increasingly, researchers recognize that during the early Edo period, Zhuxi studies did not achieve the status of official orthodoxy, and even Confucianism itself did not enjoy absolute dominance. Unlike in Ming and Qing China, where Confucianism became the primary intellectual tradition for the scholar-official class, Neo-Confucianism in Japan remained a foreign cultural import. This gave Japanese intellectuals a distinct perspective on China’s imperial rule, prompting them to selectively adopt Neo-Confucian ideas according to Japan’s unique societal needs. Moreover, Japanese scholars consciously sought to integrate Neo-Confucianism with native Shinto traditions. Even Yamazaki Ansai, who pursued a purer form of Zhuxi studies, developed the renowned Suika Shinto, which blended Confucian and Shinto elements. Thus, the Edo period was characterized by a convergence of diverse intellectual traditions, collectively moving toward greater accessibility and secularization.

Overall, the divergence between mainland Confucianism and Japanese Confucianism was a gradual process of localization. In China, Neo-Confucianism was interwoven with Buddhist and Daoist philosophy, presenting itself as a rational and metaphysical system. In Japan, however, Confucianism emphasized the practical application of social morality, merging with indigenous religious culture to form a Confucian tradition deeply imbued with social and national characteristics. From the perspective of the methodology of intellectual history, the case of Ekiken reveals the composite nature of Tokugawa scholarship. Horizontally, it was influenced by contemporaneous transformations in Chinese Confucianism; vertically, it inherited Japan’s indigenous Shinto traditions. The result was the formation of a theoretical framework marked by distinctly local characteristics. Ekiken was neither a thoroughgoing rebel against Zhuxi studies nor a mere imitator of Chinese thought. Rather, he was a thinker who actively engaged in cultural selection and theoretical reconstruction within the broader dialogue of East Asian civilizations.