Kūkai

David L. Gardiner

In addition to being the founder of the influential Shingon school of Japanese Buddhism, Kūkai (774–835) was one of Japan’s greatest calligraphers, a masterful scholar of pre-Tang dynasty classical Chinese literature, a ritual innovator, and an institutional builder who developed influential networks of relationships among Buddhist monastics, political leaders, and powerful aristocrats alike. Within the circles of Buddhist theorists and practitioners at a very formative early period in Japan’s history, his creative rendering of theological perspectives on contemplative ritual effectively galvanized existing practices with a novel esoteric Buddhist perspective on the means and ends of religious practice itself. His promotion of new approaches to the value of chanting scriptures, adorning sacred spaces, and imagining a more perfect world – within a highly articulated Mahāyāna Buddhist ‘mandalic’ vision of the cosmos – had a lasting impact on Japanese culture, religious and beyond. He became a prominent cultural hero for these accomplishments and others, some of admittedly questionable authenticity. Regardless, his saintly status has sustained centuries of reverence in the domains of pilgrimages to sacred sites related to his life, and a belief that he never died but entered a state of suspended samādhi (meditative concentration) in which he awaits the arrival of the future Buddha Maitreya. As one of Japan’s most celebrated cultural figures, Kūkai’s contributions in the religious sphere deserve substantive attention.

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KūkaiKōbō DaishiShingonEsoteric BuddhismJapanese BuddhismMikkyōVajrayānaMandalaRitualEmbodiment

1 Introduction

Kūkai 空海 (774–835) is one of the most fabled figures in Japanese history. The ancient wooden mausoleum that purportedly holds his remains is the central focus of one of the largest and most majestic burial grounds in Japan, the Okunoin 奥之院, in the small town of Koyasan 高野山 in Wakayama prefecture (designated as a UNESCO World Heritage Site, 2004). Over one million people visit Koyasan each year, including an increasing number of international tourists in addition to throngs of white-robed pilgrims dedicated to honouring Kūkai’s life and spirit (many consider him still alive in the mausoleum). Thousands visit Koyasan as part of a larger pilgrimage to some or all of the eighty-eight sacred sites on the island of Shikoku believed to be related to his own spiritual peregrinations (Reader 2004). He is revered by many as a saint. Kūkai was a Buddhist monk who founded the Shingon 真言 school of Japanese Buddhism after studying in China for two years. He was also a prolific author of influential theological works, a master of classical Chinese literary forms and calligraphy, a bibliophile par excellence, and a ritual expert who established multiple centers for Buddhist practice that remain active today. Kūkai possessed abundant social connections and political savoir faire that enabled him to establish a lasting foundation for religious life that incorporated a complex cosmology, intricate ritual, and rich iconography of paintings (especially mandalas) and statues that came to adorn elaborate spaces in Buddhist temples throughout Japan and even in the Imperial Palace.

The Okunoin cemetery in Koyasan holds not only Kūkai’s remains – or his living body according to many faithful – but also has miles of paved paths through a hauntingly beautiful forest of centuries’ old, towering cryptomeria trees and thousands upon thousands of moss-covered gravestones memorializing members of the imperial family, famous religious and military leaders of Japanese history, as well as aristocrats and commoners alike who were fortunate enough to be honoured in this special place. Legend has it that Kūkai awaits the coming of the future Buddha Maitreya, and will arise at that time. In the meantime, his many followers frequently chant his name to receive blessings: Namu Daishi Henjō Kongō. A century after his ‘passing’ he received the posthumous title ‘Kōbō Daishi’ 弘法大師 from the emperor, meaning ‘great teacher who spread the dharma [Buddhist teachings]’. Those who revere him do not usually refer to him by his monastic name, Kūkai, but rather by his title, which they often replace with the more intimate ‘O-Daishi sama’ (honourable great teacher).

Some tourists visit Koyasan simply because it is an attractive small town on top of Mount Koya with over one hundred Buddhist temples, many with intricate medieval architecture and lush gardens. Three hours south of Kyoto (or two from Osaka), its 2500ft (800m) altitude makes it notably cooler in the summer. Many of the temples offer lodging for visitors that includes a traditional vegetarian dinner and breakfast, and rooms with tatami mat flooring (soft woven-straw panels) and futon bedding. The town resembles both an outdoor and indoor museum with majestic buildings and gardens throughout. The glorious grounds of Okunoin grace the town’s the eastern end, and form the central focus for most visitors. Many Japanese visit because one of the local temples is the caretaker of their ancestor’s cremains and so the descendants attend memorial services (annually or less frequently). Kūkai, however, is honoured daily. Specially trained Buddhist priests prepare a meal for him every morning and ritually place it, with prayers, in front of the mausoleum (Nicoloff 2007).

Legends about Kūkai include that a ritual implement he threw into the sky from his boat when returning from China landed in a tree on Mount Koya. Hence, it became the location for his monastery ten years later. Also, his calligraphic prowess was said to be such that he once wrote on a massive mural using a brush in each hand, both feet, and his mouth. He is also credited with civil engineering skills (building a reservoir), creating masterful wooden sculptures of Buddhist images, and inventing the Japanese syllabary (phonetic alphabet) that came to be combined, around a century after Kūkai’s life, with Chinese graphs. The truth value of these legendary accomplishments aside, his documented achievements are surely noteworthy, and we can trace his footsteps from 804 onward with confidence in many details. What follows includes a brief biographical sketch, a summary of the main ideas of his best-known writings, and an accounting of the lasting impact of his life’s work.

2 Outline of Kūkai’s life

2.1 Early life before traveling to China

Prior to his departure to China in 804, we have only fragmentary knowledge of his movements. Born on the island of Shikoku in 774 (there remain debates about the town of his birth), he followed generations of his family to the national college in the capital city of Nara, where he concentrated in classical Chinese literature. Chinese was the only written language in Japan at the time, and it appears Kūkai not only learned to read and write it with great command but likely learned to speak it as well. However, according to his own written account, his encounters with Buddhist meditation outside the life of the college impelled him to leave formal schooling after several years in favour of the semi-formal life of a monk. He became a ‘self-ordained monk’ (shidosō), a status discouraged by the government that controlled monastic ordination procedures. He wrote the Rōkoshiiki (‘Indicating the Destination for the Deaf and Blind’) in 797 as a partly fictional account of his life focusing on explaining why taking the Buddhist path as opposed to that of Confucianism and Daoism was a superior choice (revised in 804 as Sangōshiiki, ‘Indicating the Destinations of the Three Teachings’; Hakeda 1972). It is unclear how he managed to join an imperial mission of three boats to China in 804, but it likely owed to his familial connections and his mastery of Chinese. He was sponsored by the government as a student-monk with a stipend intended to last twenty years. At the time, monastic ordinations were administered by the national government such that monks were effectively employees of the state whose knowledge, presumed ethical purity, and ritual expertise (in particular, the recitation of Buddhist scripture) all advanced the interests of the ruling elite. It appears that Kūkai received formal ordination just prior to his departure so that his monastic status was legitimate. At this relatively early stage in Japanese history, in order to enhance its prestige and power the ruling house desired to learn about law, architecture, literature, religion, and more, from the highly developed civilization of Tang dynasty (618–907) China. Kūkai’s target was aspects of Buddhist learning – from texts, meditation, ritual practice, and art. He was also likely determined to learn more about specific Buddhist scriptures he had read that no one in Japan could explain.

An early biographical account says that a chief reason for his wanting to travel to China was to find someone to help him decipher the esoteric language of the Chinese translation of the Mahavairocana-sutra (Dainichi-kyō in Japanese). This seventh-century Indian Buddhist text offers one of the earliest expositions of tantric Buddhist (also known as esoteric Buddhist or Vajrayāna) ritualized cosmology (Hodge 2003; Giebel 2005). Kūkai’s Sangōshiiki further notes that his experience with meditating in accordance with a method called the Kokūzōgumonjihō enticed him with a yearning for a deeper contemplative state (Kasulis 1988). This meditation focused on chanting a mantra of the deity Kokūzō (or Ākāśagarbha, meaning ‘womb of space’ in Sanskrit) with the belief that it would improve memory. One possible reward of such efforts is reported to have been enhanced performance in Buddhist text memorization that was required to pass ordination exams. A group of monastics loosely called the ‘natural wisdom school’ (jinenchi-shū) engaged in such Buddhist and other ascetic practices in the mountains near the capital city of Nara. Kūkai’s involvement in the communities of Buddhist monks in the city and the countryside, and his experiences in meditation, seems to have stimulated his passion for forms of study outside the limits of the formal education offered by the government college.

While Kūkai’s writings later distinguished the kind of Buddhist practice he learned in China as being superior to anything available in Japan, various people in Nara were already engaging with texts and practices related to Kokūzō and other Buddhist deities central to the form of religion he eventually promoted as ‘esoteric’ (Abé 1999: 151–184; Beghi 2011; Ford 2011; Gardiner 2018). Kūkai’s Shingon school, formally established in 823, focused on the chanting of mantra (shingon, meaning ‘true words) along with specific ritual gestures (mudrā) and the use of mandalas. Later Shingon exegetes framed Kūkai’s systematized model of practice as representing the ‘pure esoteric’ (junmitsu) in contrast to prior forms being ‘miscellaneous esoteric’ (zōmitsu). Despite this value-laden distinction, a strong thread of continuity across these forms was the application of practices toward worldly accomplishments such as preserving long life, averting disaster, and protecting the nation. Kūkai can at minimum be credited with developing a theoretical framework for systematizing existing ritual practices together with new ones he imported (Abé 1999). Furthermore, the spiritual motivation of a genuine Shingon practitioner is expected to maintain the Mahāyāna Buddhist bodhisattva ideal of practicing for the sake of all sentient beings, such that they may eventually liberate themselves from every form of suffering, and not only toward the temporary alleviation of mundane discomforts.

2.2 Kūkai’s stay in China

Kūkai traveled on one of three government sponsored ships as part of a series of regular missions to China (Abé 1999: 113–120; Borgen 1982). The ship had gone off course due to rough waters and landed farther south on the coast, and much later, than expected. Local Chinese officials were not welcoming and apparently it took Kūkai’s drafting of an elegant plea on behalf of the mission for them to be granted entry (Borgen 1982: 26–28). Permission to travel north to the capital of Chang’an (modern day Xian) also took time, and it was well over a month before a small portion of the mission was able to reach the capital. Kūkai was permitted to reside at the Ximingsi 西明寺 temple, which for over a century had hosted famous Chinese and Indian scholars and translators, and was known for its vast library. He wrote that he studied Sanskrit there with the monk Prajñā, who was from the region of modern Afghanistan and had translated several Indian Buddhist texts into Chinese. Within a few months, Kūkai moved to the Qinglongsi 青龍寺 temple where he was able to study closely with the monk Huiguo 惠果. It appears that Huiguo took Kūkai under his wing for intensive study of the tradition of esoteric Buddhism he had trained in under Amoghavajra (Abé 1999: 120–127; Orzech 1989). Amoghavajra (Chinese: Bukong 不空) was a prolific translator whose writings and translations had an enormous impact on Chinese Buddhism as well as on the ruling elite (Goble 2019; Orzech 1989). He became so closely affiliated with the throne that he performed an esoteric abhiṣekha initiation for emperor Xuanzong in an altar that Amoghavajra designed for the palace. Kūkai not only relied deeply on Amoghavajra’s written works but likely also modeled his own activities in Japan on those of his teacher’s teacher. According to Kūkai’s account, in only a matter of months Huiguo had mentored him so closely that he told Kūkai he was qualified to transmit the esoteric teachings and practices to Japan.

Huiguo died about six months after meeting Kūkai, and it appears that an epitaph for him was written by his relatively new foreign disciple (Green 2015). As does Kūkai’s Catalog of Imported Items, the epitaph for Huiguo depicts the master as eager to pass on all he can to his disciple so the latter can return to Japan to benefit beings there with these powerful teachings. Kūkai even writes that the night before he departed from China, his deceased master appeared to him in a dream and told him that the two of them had been working together to promote the Buddha-dharma for lifetimes, alternating as teacher and student (Green 2015: 160).

Photograph of a bronze statue depicting Huigo delivering a scroll to Kūkai.
Figure 1. Bronze statue of Huigo transmitting esoteric teachings to Kūkai, Qinglongsi temple, Xian, China (photograph courtesy of author).

Kūkai’s Shorai mokuroku (Catalog of Imported Items, 806) offers the following account of his time with Huiguo:

I was fortunate enough to meet the ācārya (master) of abhiṣeka (esoteric ritual initiation) of Qinglong Monastery whose Buddhist name was Huiguo; he became my teacher […]. Three times I was bathed in the abhiṣeka in order to receive the mantras and once to inherit the mastership […]. This teaching is as useful to the nation as walls are to a city […]. I have now imported the teachings of the diamond vehicle (Vajrayāna) contained in more than one hundred texts and the dual mandalas […] due to the effect of His Majesty’s influence […]. This teaching is the very heart of all the buddhas and the direct path to perfecting buddhahood. (Gardiner 2024: 23)

And around 815, when he began a determined effort to share esoteric Buddhism more fully, he wrote similarly in a letter (the Kan’ensho) sent to multiple acquaintances throughout Japan asking for assistance in making copies of texts he acquired in China:

I traveled afar to the great Tang in search of the profound Dharma. I had the good fortune to encounter the ācārya Huiguo of Qinglong Temple, who was a direct disciple of the late master Bukong. From him I received instruction in the secret, unsurpassed vajra vehicle of supernatural powers […]. Reverently complying with the instructions of my master (Huiguo), I applied myself to the practice and made a vow to promulgate it. And yet, although several years have passed since I returned to the homeland, conditions have not been receptive and so I have not been able to spread [the teaching] extensively. [Meanwhile,] the passing of time is impossible to halt; like [flowing] water and [the changes of] the moon, it steadily advances. Having made a vow to promulgate [this teaching], how can I bear to remain silent any longer? […] Since at present I am unable by myself to fulfill my vow to benefit beings by spreading this teaching, I have no recourse but to trouble those of you who have affinities with the teaching by this request for your help. (Gardiner 2003: 51–52)

Although it is abundantly clear how great Kūkai’s esteem was for Huiguo, various scholars including Ronald Green (2015) have argued that his account exaggerates Huiguo’s status within the tradition of esoteric Buddhism in China. It has been pointed out that Huiguo was not the chief disciple of Amoghavajra (Kūkai does not mention any of the others) and, furthermore, that there is no precedent for the narrative Kūkai offers that places Huiguo as the seventh ‘patriarch’ in a lineage of teachers of esoteric Buddhism, making Kūkai the eighth. Notwithstanding, this narrative remains central to the identity of adherents to the Shingon tradition in Japan. Since there are no extant writings attributed to Huiguo, we do not have access to his perspective on these matters. It is fairly clear, however, that in the early ninth century those who practiced and studied forms of esoteric Buddhism in China did not consider their commonalities as constituting a particular ‘school’, such as the Faxiang, Huayan, or Tiantai schools that were so identified (Goble 2019; Sharf 2005). Thus, it is reasonable to hold the view that Kūkai not only established the Shingon school in Japan but in doing so also created – in the imagination of many – a belief that this school was a direct transmission of its Chinese antecedent (Orzech 1989).

2.3 Return to Japan

When Kūkai returned to Japan in 806, he arrived in Dazaifu on the southern island of Kyushu where his trip had originated. Dazaifu was an important city for official cultural exchange between Japan and China, serving both as a place to receive foreign emissaries and a place from which Japanese missions abroad were launched. Possibly due to unsettling political circumstances in the new capital at Kyoto (established in 794), it appears that Kūkai was unable to enter the capital until 809 and so remained in Dazaifu. While residing there, he seems to have been productively engaged making acquaintances and sorting through the massive volume of items he brought back from China (Bogel 2010; Gardiner 1999). The relationships he developed while in Kyushu are evident in letters he later wrote from the capital – requesting assistance and thanking people for helping him promote his new esoteric dispensation – and in documents he wrote to perform memorial rituals in Dazaifu (Gardiner 1999). The Catalog of Imported Items he sent to the court in Kyoto included a long list of texts and various kinds of artwork, including specialized ritual implements (Bogel 2010: 112–140). Clearly, Kūkai was intimately familiar with the contents of the libraries at the major Buddhist monasteries in Japan because the texts he brought back were with rare exception all new to Japan. One of the most eminent monks in Japan at the time, Saichō 最澄 (767–822), who sailed on another boat in the same mission as Kūkai but returned earlier, was so impressed by the contents of Kūkai’s Catalog that he made a copy in his own hand (that remains extant today). Saichō’s closeness to Emperor Kanmu and his court permitted him access to the Catalog. Once Kūkai entered the capital in 809, Saichō borrowed as many texts from him as he could to make copies. He also introduced Kūkai to monks and laypersons alike interested in learning about the new esoteric practice he had learned. Kūkai’s emergence as a sought-after teacher and ritual master in subsequent years owed much to his early friendship with Saichō (Abé 1995; Gardiner 2003; 2024).

Saichō went to China to study the Tiantai 天台 (Jpn. Tendai) Buddhist tradition. It appears that Emperor Kanmu sponsored Saichō with an aim to creating a more harmonious foundation for Buddhist institutions in the new capital, and perhaps in particular to quell the doctrinal antipathies (and attendant political rivalries) that had emerged between the Hossō 法相 and Sanron 三論 schools in Nara (based on the Chinese developments of the Indian Yogacāra and Mādhyamaka traditions) (Groner 2016). Saichō’s Enryakuji temple on Mt. Hiei in the northern hills of the capital was the first monastic Buddhist establishment permitted in Kyoto. For many years Saichō provided training for monks there and he prayed for Kanmu’s health prior to the emperor’s death in 806. However, Saichō’s single-minded devotion to the Tendai tradition’s unique theories and practices as being ‘superior’ to the traditions emphasized in Nara contrasted with the interest the emperor and many others had in the purported power of esoteric rituals for healing and protection. Thus, Kanmu required that Saichō incorporate esoteric ritual training as part of his Tendai monastic curriculum. To make this possible, Saichō enlisted Kūkai’s assistance by borrowing his texts and sending his top disciples to study with Kūkai. While the two of them appear to have cooperated for a few years in nurturing forms of esoteric Buddhist study, by 813 their relationship experienced a rupture and they went separate ways. Their priorities were not mutually aligned (Abé 1995; Groner 2016; Gardiner 2003; 2024). Nonetheless, the people that Saichō introduced to Kūkai and the esoteric ritual ceremonies (abhiṣekha; Jpn. kanjō) he organized Kukai to perform at Takaosanji, for hundreds of monastics from Nara as well as lay nobles, were instrumental in launching Kūkai’s career as a new Buddhist leader.

2.4 Emerging as a prominent public figure

2.4.1 Overview

From around 815, Kūkai’s efforts to promote the new teachings and practices kicked into high gear. He sent a letter to multiple people in eastern and western Japan – by personal messengers each carrying a trove of new texts – to request help getting copies made to enable study across the land (the Kan’ensho, cited above) (Gardiner 2003; 2024). At about the same time, he wrote the Treatise on the Two Teachings, Exoteric and Esoteric (Benkenmitsu-nikyōron), which like the Kan’ensho clarified his view on how ritualized contemplative practices based on the new esoteric scriptures offered unparalleled access to deep states of spiritual realization. During the next several years he also composed his major works on esoteric Buddhist theory and practice: Realization of Buddhahood with This Body (Sokushin jōbutsu-gi), The Meaning of Sound, Word, and Reality (Shojijissōgi), The Meaning of the Word ‘Hūm’ (Unjigi), and The Secret Key to the Heart Sūtra (Hannya shingyō hiken) (partial translations in Hakeda 1972). In 816, Kūkai requested and was granted permission by emperor Saga (r. 809–823) to build a monastic center on top of Mount Koya, a few days by foot southwest of Nara. In 822, he managed to create a hall for esoteric initiations at the Tōdaiji temple in Nara, which served as the central administrative temple of a national network of temples and was the designated place for monastic ordinations in the capital region. It appears that the meditation practices he introduced quickly became popular at temples associated with all the other schools of Buddhism. His leadership qualifications were also recognized by his being appointed to the national Office of Priestly Affairs, the Sōgō, in 824 and being designated as its director, Daisōzu, in 827.

Kūkai was active not only in the writing of poetry (one of his poems was included in the 827 Keikokushū imperial anthology), but in writing about the vast poetic traditions of China. His close relationship with Emperor Saga was surely due more to their mutual interest in poetry than in Buddhism. His 819 Bunkyō hifuron was ‘an extensive compendium summarizing the major poetic theories and rhetorical strategies of classical Chinese literature and a work that had a lasting influence on the development of Japanese poetry and poetics’ (Abé 1999: 104; see also Bodman 2020). His profound knowledge of and interest in classical Chinese language was further expressed in his 828 authoring of the Tenrei banshō meigi, one of Japan’s earliest Chinese dictionaries that, while based on an earlier one produced in China, nonetheless demonstrated his fascination with language and bibliophilic familiarity with a variety of dictionaries in China (Bailey 1960).

2.4.2 Constructing, managing, and growing institutions

Having been granted permission in 816 to develop a monastic compound (Kongōbuji) on Mount Koya, Kūkai began construction there in 819. In a votive document honouring the formal ritual for ‘drawing the boundary’ (kekkai 結果) of the compound, he wrote that the presence of esoteric practice there amounted to ‘establishing both the great mandalas’. As a section below explains, ‘mandala’ in general refers not only to elaborate painted icons with deities but, on a psychological level, to states of mind that embody aspects (in this case, two complementary ones) of truth:

In order to repay above the kindness of the buddhas by spreading the esoteric teaching, and to augment below the resplendence of the five kinds of deities by liberating sentient beings, in sole reliance upon the esoteric teaching of the Vajrayāna, I wish to establish [here on Mount Koya] both the great mandalas of the Matrix and Vajra realms. With reverence I beseech all the buddhas to rejoice in, and all the devas to protect, my efforts here and ask that all virtuous spirits vow to help realize my wishes. (Gardiner 2000: 128)

His correspondences reveal how difficult the task was to build Kongōbuji since it was far from both the new and the old capital, and on top of a mountain in the wilderness. Until his death in 835, he divided his time between official duties in the capital, mentoring people and offering initiations into esoteric Buddhist practice in Nara, and finding his way to the mountaintop to supervise the early construction of the complex there. The complex was not completed during his lifetime but by one of his successors, Shinnen 真然 (804–901). The center of the complex was designed as two stupas signifying the two realms (and their corresponding two mandalas) of Shingon practice: the Vajra Realm (kongōkai 金剛界) and the Matrix Realm (taizōkai 胎蔵界) (Gardiner 1996). The mandalas are symbolic representations of the unfathomable depths of reality (Vajra Realm) and richness of creation of the world of experience (Matrix Realm) when explored through Shingon practice.

In the capital area, Kūkai was recruited by Emperor Saga to supervise the construction of one of the first three Buddhist temples to be located within the city limits, the Tōji 東寺temple. It stood on the eastern side (its name meaning ‘eastern temple’) of the original main gate on the south border of the capital while Saiji 西寺was placed to the west. Only Tōji remains, with its exquisite five-tiered stupa. In 823, Kūkai’s request for Tōji to be used exclusively by monks initiated into the esoteric practices was approved. He devoted a great deal of time not only to securing materials and labor to build the Tōji complex but to train its monks as well. At the same time, he was often in Nara conducting rituals and instructing people in esoteric practice. In 822, he established an initiation hall for exoteric practice (kanjōin 灌頂院) as part of the Tōdaiji temple complex (the headquarters of Japan’s national temple network) and in 829 was assigned to be the administrator (bettō 別当) of the important Daianji 大安寺 temple in Nara. While in the capital he also participated in the cultural salons at the court, where the emperor’s literary interests benefitted greatly from Kūkai’s unsurpassed knowledge of Chinese poetry and literature. The two of them were both expert in calligraphy and together with Tachibana no Hayanari 橘逸勢 (782–844) – who traveled as a government official on the same mission to China as Kūkai – were renowned as Japan’s three greatest calligraphers of the early Heian period.

In 835, in the innermost sanctum of imperial government, the emperor’s palace, Kūkai succeeded in installing a special chapel for Shingon practice (the Shingon’in 真言院), just a few months prior to his death. There he officiated over a one-week ritual for the welfare of the nation, called the Goshichi nichi mishuhō. The rite took place during the second week of the new year, following the first week’s annual Misae ceremony. In his petition requesting permission to perform the rite, Kūkai wrote that it would be comprised of

[…] fourteen monks skilled in ritual and fourteen novices […] who while reading the scripture properly will for seven days arrange the sacred images, perform the necessary offerings, and chant mantras in a specially adorned room. If this is done, both the exoteric and esoteric teachings, which express the Buddha’s true intent, will cause great happiness in the world and thereby fulfill the compassionate vows of the holy ones. (Gardiner 2024: 27; for more on this text, see Ruppert 2000: 102–125)

2.4.3 Significant writings

It is generally assumed that Kūkai wrote his key texts clarifying the outlines of his esoteric Buddhist system of thought and practice during roughly a nine-year period spanning from 815 to 824. During this time his main residence was likely the Takaosanji temple northwest of the capital, where he first gave esoteric initiations to Saichō and many others in 812–813. He also often traveled to Mount Koya and spent time in Nara, which was more or less on the route between the capital and Koyasan. These texts were: Treatise on the Two Teachings, Exoteric and Esoteric (Benkenmitsu nikyōron), Realization of Buddhahood with This Body (Sokushin jōbutsugi), The Meaning of Sound, Word, and Reality (Shojijissōgi), The Meaning of the Word ‘Hūm’ (Unjigi), and The Secret Key to the Heart Sūtra (Hannya shingyō hiken). Then there was likely a gap of a few years before he wrote his magnum opus Ten Stages of Mind of the Secret Mandala (Himitsu mandara jūjū shinron 秘密曼荼羅十住心論), composed in response to the emperor’s request that each of the six established schools in Japan (Sanron, Hossō, Kegon, Ritsu, Tendai, and Shingon) submit in 830 a summary of their teachings. Due to the perceived excessive length of the Ten Stages, Kūkai complied with a request to submit a shorter, simplified version titled Precious Key to the Secret Treasury (Hizō hōyaku 秘蔵宝鑰) soon afterward. While each of these texts possesses layers of complexity in terms both of philosophy and of implications for contemplative practice, their key ideas can be summarized as follows.

Treatise on the Two Teachings, Exoteric and Esoteric likely came first as an announcement of the unique quality of the new dispensation of the esoteric texts and practices he brought back from China. The text critiques existing forms of Buddhism in Japan for sharing a perspective regarding the utterly transcendent nature of ultimate reality. It refers to the existing traditions of practice as being based on an exoteric paradigm that understands the verbal teachings of the historical Buddha (Śākyamuni) as having indicated that the highest truth is a domain where ‘language is cut off and mind ceases’ (gongo dōdan, shingyō shometsu 言語道断 心行所滅). Kūkai writes that this may be a sound view for unenlightened beings, but from a buddha’s perspective, there does exist enlightened speech and mentation that are inseparable from ultimate reality. Moreover, he asserts that it is via the medium of esoteric Shingon practice that one comes to see this truth and to embody it fully. He cites a handful of the new texts in his possession to support this claim (Gardiner 2024: 131–154).

Realization of Buddhahood with This Body lays out reasons for the esoteric Buddhist view that its ritual contemplative practices enable one to achieve complete enlightenment much faster than the standard (exoteric) account, which says the bodhisattva path to buddhahood requires cultivating the virtues related to both wisdom and compassion across multiple, if not myriad, lifetimes. The Vajrayāna tradition of India asserted its path was ‘sudden’ in the same way. Kūkai cites some esoteric Buddhist texts that make this claim and he champions the Shingon tradition’s unique methods for accomplishing it. The text’s focus, however, is less on rapidity than it is on the metaphysics that make it possible. Even the first two words of the title – soku shin 即身 – hold a double meaning in Kūkai’s treatment. They can refer to ‘this body’ as meaning this lifetime, but they also point to the very nature of this fleshly body as being marvelously interdependent, free from the fixations of time and space. Kūkai adeptly develops an account the entire cosmos – sentient and non-sentient, awakened and unawakened – as being comprised of the six elements of earth, water, fire, wind, space, and consciousness. And he depicts these elements not as static, independent entities but as active processes that organically flow into one another freely, following a natural principle of mutual non-obstruction. In his phrasing, this whole cosmic ‘body’ is the unified fabric of all existence, shared by Buddhas and ordinary sentient beings alike. It is the body of the ‘great illuminating one’ (Mahāvairocana; Jpn. Dainichi 大日). Kūkai equates this body – or at least its realization within a being – with the dharma-body (dharmakāya; Jpn. hosshin 法身), the dimension of an enlightened being that is free of all the obstructions of ignorance, craving, and hatred.

He affirmed that all beings share this cosmic body as part of their deepest nature, but that most are unaware of their true heritage being such. Consecrated ritual practice bridges this gap by opening one’s energies of body, speech, and mind to their deeper roots. Kūkai thus prescribes training in ‘three secrets’ (sanmitsu 三密) practice wherein one experiences at a foundational level the participation of one’s entire being in the cosmic freedom of Dainichi. The ‘body secret’ entails holding specific postures, in particular with the hands in symbolic positions known as mudrā. In this way one’s entire physical being expresses an intention related to enlightened awareness. The ‘speech secret’ practice employs the recitation of mantras in a manner that allows one to see that the vibrations of voice are an extension of the vibratory and ever-shifting feature of all phenomena. More importantly, the practitioner feels as if their speech emerges from an awakened, sacred source. Together, the body and speech secret practices galvanize one’s ordinary physical presence with a sense of being conjoined with a universal sacrality (Abé 1999: 275–304; Kasulis 1988). The ‘mind secret’ practice entails working with the images within a painted mandala diagram. Part of this practice is to imagine that one’s ordinary self is transformed into that of one of the enlightened deities of the mandala. This is done as a vivid imaginative gesture that, combined with the other two secrets, catalyses a felt sense of both mental and physical regeneration. Kūkai refers to this felt sense as a kind of inner glow that comes, at first, from a perceived outer sacred source. He uses the term kaji 加持, which can loosely be translated as ‘mysterious empowerment’. Kaji is a translation of the Indian Buddhist term adhiṣṭhāna, which has a range of meanings. One meaning is the spiritual support or blessing that drives one’s practice, especially of visualizing oneself as an enlightened being or deity in Vajrayāna meditation. When glossing his own verses in Realization of Buddhahood with This Body, Kūkai describes the experience of kaji by means of a creative exegesis, taking the two graphs 加 (ka, ‘add’) and 持 (ji, ‘hold’) as referring to two interrelated dimensions of the experience:

My verse says, ‘The mysterious empowerment of the Three Secrets quickly manifests’. ‘Mysterious empowerment’ expresses both the great compassion of the Buddha and the faith-mind of a sentient being. The reflection of the sunlight of Buddha appearing in the mind-water of a sentient being is called ‘adding’. The ability of the mind-water of the practitioner to sense this [light of the] Buddha’s sun is called ‘holding’. If the practitioner is able to contemplate this principle, then the Three Secrets [both of the Buddha and of the practitioner] will unite. In the present body one will quickly obtain the originally existent Three Buddha Bodies. Hence the phrase, ‘quickly manifest’. Just like the everyday phrases ‘at this time’ or ‘on this day,’ the phrase ‘this very body’ has the same meaning [that is, of immediacy]. (Teihon Kōbōdaishi Zenshū [TKZ] 3:23)

Kūkai’s poetic expression conveys a somatic (warmth of sunlight in water) sense of both blessing and of union. The ‘originally existent’ three Buddha bodies refers to an understanding that the three dimensions of a buddha’s awakened state (her dharmakāya, sambhogakāya, and nirmanakāya) reside within all beings as intrinsic capacities. The Three Secrets practice – when done properly on the basis of a prior initiation – is said to catalyse a full actualization of these potentialities.

In The Meaning of Sound, Word, and Reality and The Meaning of the Word ‘Hūm’, Kūkai offers tour de force explications of language on multiple levels. The first text elaborates how human speech operates in general and how mantra practice in particular can reveal depths of reality. The latter presents an elaborate exegesis of a single mantric syllable to unpack the layers of significance that esoteric texts, and by implication esoteric practices, possess.

The hidden power of ontological and epistemological multivalence is a key emphasis in both writings. The theme of hiddenness (as in ‘secret’ and ‘esoteric’) is central to much of Kūkai’s writings, and in many ways his entire corpus points from various angles to the potential all beings have for uncovering their own awakened nature. As he writes in the concluding section of the Treatise on the Two Teachings:

The meanings of exoteric and esoteric are multiple and without limit. Viewed from the perspective of shallow teachings, deeper ones are esoteric while the shallow and abbreviated ones are exoteric. Thus, even in non-Buddhist texts there are those called esoteric. In the Buddha’s teachings there are many meanings of exoteric and esoteric. In comparison with non-Buddhist teachings, the Buddha’s Hīnayāna teachings can be considered profoundly esoteric. The same distinction of exoteric and esoteric can be made when comparing the Mahāyāna and Hīnayāna, and [within Mahāyāna] the [teaching of the] One Vehicle earns the label esoteric in contrast to the Three [Vehicle teaching].

The preaching by the Dharma-body is profound and hidden, while the preaching by the Manifestation-body is shallow and abbreviated. Thus, we call [the former one] esoteric. Within the designation esoteric there are also two meanings [of secretness]. One is the secret of sentient beings [that they keep from themselves], and the other is the secret [awakened state] of the Tathāgata (Buddha). Because sentient beings cover their original nature of true awakening by ignorance and deluded thinking, we refer to their self-concealment. (TKZ 2:35)

3 Kūkai’s theologies of embodiment

3.1 ‘Mandala’ as a central concept

Just as the concentric circles of a mandala have layers, so too does the meaning of ‘mandala’. On a surface level it designates the diagrams painted on cloth or made of coloured sand (on horizontal platforms) that depict in concentric geometric shapes (circles, squares, and triangles) the images of buddhas, bodhisattvas, attendant deities, and more, that are imagined gracing the world of living beings. In the Japanese Shingon tradition, the large painted ones often come in a pair – portraying the Matrix Realm and the Vajra Realm – and can serve as sacred icons that bless a space, the beings in it, and the practice of one engaged in the Three Secrets ritual contemplation. To fill a ritual space with mandalas and other religious objects, including statues of buddhas, offerings of incense and flowers, banners and various other symbolic items is called ‘adorning’ (shōgon 荘厳) the space. Yet like ‘mandala’, the word ‘adorn’ also takes on a deeply symbolic metaphorical meaning. It can refer to the qualities of an awakened being, their virtues of wisdom, compassion, generosity, and so on. A buddha is adorned with these attributes just as a queen is bedecked with fine garments and jewellery (Gardiner 2008a).

In the esoteric Buddhist practice of Shingon, part of the ritual contemplative practice entails imagining oneself to possess both the form and the inner qualities of an enlightened being. The Three Secrets practice aims to emblazon the practitioner with the characteristics of awakened functions within body, speech, and mind. It brings about a state of kaji, or ‘mysterious empowerment’, wherein ‘the Buddha enters the person and the person enters the Buddha’ (nyūga ga’nyū 入我我入). Such a state is one of perfect adornment. What the practitioner realizes in the kaji state is a radically transformed sense of self that is liberated and enhanced. Moreover, the renewed self-sense occurs on cognitive as well as somatic levels. This ritual regeneration begets an embodied state that is itself called a mandala (Gardiner 2008a).

In Kūkai’s Ten Stages of Mind of the Secret Mandala, he writes of the highest stage of esoteric Shingon practice in terms of ‘adornment’:

The mind of secret adornment [the tenth abode] is to thoroughly awaken to the knowledge of the root source of one’s own mind and to realize, as it truly is, the multiplicity of one’s own body/ies. This [abode] is none other than the oceanic assembly [of all the deities] of the Matrix Mandala, the assembly of the Diamond World Mandala, and the Eighteen Assembly Mandala of the Vajra Peak [Sūtra]. (Gardiner 2008a: 49; TKZ 2:307)

It is noteworthy that he mentions both mind and body as being integral to awakening to the ‘root source’. It is with both body and mind that the practitioner realizes (as in, makes real) the mandala of experience that unfolds from within the state of kaji. In the same section of the text, he incorporates the remaining member of the ‘three secrets’, the property of speech:

The term ‘adornment’ refers to the universal manifestation of all manner of sacred deportment from the single equality of body. There is nothing among these sacred deportments that is not a secret seal [that is, that does not express reality]. From the single equality of word manifests all sounds. There is nothing among these sounds that is not mantra. From the single equality of mind manifests all of the sacred ones (honzon). There is nothing among these sacred ones that is not an expression [of their vows; sammaya]. Every single one of the distinct marks of these three activities [of body, speech and mind] are without limit and unfathomable. Therefore, we speak of ‘inexhaustible adornment’. (Gardiner 2008a: 49; TKZ 2:316)

In a summary statement, Kūkai points to the realization that it is not just one’s individual body, speech, and mind that are transformed, but that the practice opens up one’s experience to the unfathomable, limitless nature of these three dimensions of being within an envisioned and embodied sacrality that pervades the entire universe: ‘The Three Secrets as numerable as particles of dust are the adorned body and land [of enlightenment]. This is called mandala’ (Gardiner 2008a: 53–54; TKZ 2:318).

3.1.1 The two mandala worlds: Vajra and Matrix

The Shingon tradition employs two mandala images as sacred icons that represent dual aspects of its cosmology (see mandala images below). They are known as the Mandalas of the Vajra Realm (Kongōkai) and the Matrix Realm (Taizōkai). The Vajra Realm mandala derives from an Indian model that became prominent in later centuries and that extended into Tibetan religious culture. This is the Vajradhātu mandala that embodies the Five Buddhas, each symbolically representing a cardinal direction and its corresponding wisdom. The Taizōkai mandala was likely developed in China, while the Kongōkai (Skt, Vajradhātu) mandala was conceived in India. In ritual settings, the two mandalas are hung left and right, symbolizing a balance or, better, a non-dual relationship. The mandalas are often said to represent qualities such as centripetal and centrifugal energies, and wisdom and compassion. Contrary to some popular interpretations, mandalas are not so much maps depicting the universe in a material sense but, instead, depictions of a vision of the cosmos as a vast matrix of sacred and profane dimensions interpenetrating one another, of mind and world as inseparable, or depictions of how enlightened awareness fully cognizes, and thus even embodies, all of reality and as such is not limited to being merely a ‘mental state’. In Shingon parlance, as articulated by Kūkai, the two mandalas are also said to represent truth (or ‘principle’, ri 理, for the Matrix Realm) and wisdom (chi 智, for the Vajra Realm), which two aspects are, in the awakened state, inseparable (richi funi 理智不二). The cosmic Buddha Mahāvairocana (Jpn., Dainichi-nyorai 大日如来) resides at the centre of both mandalas, representing the profound unity of all dimensions of existence.

Buddhist mandala depicted on a silk hanging with the repeated motif of buddhas arranged in nine squares. A single larger buddha occupies the top centre square.
Figure 2. Kongōkai (Vajra Realm) mandala, 9th century. Public domain, via Wikimedia Commons.
Buddhist mandala depicted on a silk hanging with the repeated motif of buddhas arranged in rows around a central square containing nine buddhas in a lotus shape.
Figure 3. Taizōkai (Matrix Realm) mandala, 9th century. Public domain, via Wikimedia Commons.

3.1.2 Hosshin seppō: the dharma-kāya preaches the Dharma

In both mandalas, Dainichi-nyorai represents the dynamic nature of reality on multiple levels. On one level, Dainichi is said to the be dharma-kāya or ‘body of truth’. This term refers to the dimension of total freedom of mind that all buddhas share. It is the aspect of their cognitive functioning that is entirely free from all traces of ignorance that mistakenly projects the qualities of permanence, independence, and substantiality to all phenomena. This freedom is a natural consequence of the perfection of wisdom: a buddha’s ability to cognize all things as they truly are, as empty of the above projected qualities. Although commonly considered a rarefied mental state purified of all cognitive obstructions, dharma-kāya also pervades the entirety of a buddha’s being: all verbal and physical activities are equally purified of perversion, resulting in a thoroughly wholesome embodiment. As such, dharma-kāya signifies a profound existential release from all samsaric constraints. It is a buddha’s state of being grounded in the ultimate reality of emptiness, of groundlessness. As such, it is an embodiment of complete freedom from the actual sources of suffering. And, while the two other ‘bodies’ (or embodiments) of a buddha – dimensions that appear in either subtle or gross manifestations to guide living beings – are spontaneous outgrowths from the dharma-kāya, they are said to be ‘form bodies’ as opposed to ‘truth/reality bodies’. That is, they are outwardly directed, compassionate expressions of a buddha’s inner freedom that appear to the minds and bodies of others as liberative lures. They engage in ‘expedient means’ (upāya) capable of pointing beings toward paths of their own freedom.

Since the dharma-kāya is commonly understood to be the embodied dimension of formless freedom achieved by perfected insight into the emptiness of all phenomena, it is commonly understood to be ‘formless’, and as thus being imperceptible via sight, sound, or touch. Therefore, it does not guide or teach beings; the other two ‘form bodies’ do this. Kūkai, however, challenged this traditional doctrinal perspective on the embodiments of enlightenment by asserting that the dharma-kāya does preach the Dharma. He even established the idea of the ‘preaching of Dharma by the dharma-kāya’ (hosshin seppō 法身説法) as a foundational element of Shingon theory and practice. He seemed intent upon affirming at once both the transcendence and immanence of the dharma-kāya; the phrase hosshin seppō encapsulates this paradoxicality (Gardiner 2008b; Kasulis 1995; Rambelli 1994).

Kūkai’s writings explicitly critique a radically transcendentalist metaphysics that posits the existence of ultimate reality as being ‘absolutely removed’ (zetsu ri 絶離) from our conventional world. And, while he may have overstated the extent to which representatives of mainstream Buddhist schools held such a view, his emphasis is consistent with standard Mahāyāna interpretations of emptiness as being neither a something nor a nothing, but instead as designating only (and precisely) the absence of an independent, permanent, and findable identity in anything. He lamented what he characterized as a tendency to hypostasize a higher, unreachable, absolute reality by citing well-known Buddhist texts composed by revered masters of established schools that reference ultimate truth as being beyond words and thoughts (gongō dōdan, shingyō shometsu 言語道断 心行處滅). Instead, he affirmed the power embedded within esoteric Buddhist ritual practice to access a completely enlightened state wherein body, speech, and mind accord perfectly with the ultimate nature of things (i.e. as an expression of wisdom), yet simultaneously and spontaneously respond to sentient beings’ suffering (an expression of compassion). This is the state of ‘mysterious empowerment by the Three Secrets’ (sanmitsu kaji 三密加持). It can be described as a moment when the practitioner and the awakened state of buddhahood are inseparable (yuga ga’nyū 入我我入), and the Two Truths are perfectly integrated.

Kūkai’s depiction of the non-esoteric Buddhist schools as clinging to an absolutist dualism is probably more a caricature of a potential misdirection inherent in their claim that ultimate reality is beyond words and thoughts than it is an accurate portrait of an entrenched ontological view. Nonetheless, his rhetorical stance can be seen as highlighting the danger of misconceiving the ultimate reality that is emptiness as either being a something or a nothing. Traditional accounts of emptiness clarify that it is a ‘middle way’ between the two extreme views of substantialism (that phenomena possess an inherent, permanent essence) and annihilationism (that nothing at all is real). The emptiness teaching expresses that all existents – including our various states of suffering – are dependent and impermanent. As a consequence, no being is ‘stuck’ in their suffering; they can move toward liberation by cultivating the path. In this light, the thrust of his critique is aimed at clarifying the tremendous potential that the truth of emptiness holds for a practitioner’s capacity to actualize awakening in/with this body. The steady pulse of his exhortations affirming the unique power of esoteric Buddhist practice speaks to the urgency of his vision, and possibly to his frustration that other forms of practice (and theory) he witnessed around him were not graced by the confidence that realization is immanently possible. His impassioned mission was to integrate Shingon esoteric practice into the mainstream fabric of Buddhism in Japan.

It is reasonable to describe the ritual contemplative practice of the Three Secrets as a reenactment of the state of perfect enlightenment, or as an imitation that resembles the cosmic and sacred order of buddhahood. It is in this sense that the practitioner is said to embody the union of the worlds of the two mandalas. Rather than ‘secrets’, Thomas Kasulis (2008) has suggested translating mitsu as ‘intimacies’. His rendering suggests the deep connection, or profound felt-sense of union, between the two domains/worlds that can otherwise be understood in terms of various pairings (in the pairings, the first represents the Diamond World and the second the Matrix World): the diamond-like realization of wisdom (as subject that cognizes truth as object) & the matrix-like dimension of the interdependent world of existence (as the object realized by wisdom); ultimate reality/truth & conventional reality/truth; wisdom & compassion. The intimacy (also translatable as ‘secret’ or ‘mystery’) lies in the paradoxical relationship of dimensions that are ‘dual but not apart’. It is an intimacy also suggested by Kūkai’s significant employment of the term soku 即, which denotes a state of mutual identity or union. His famous text The Meaning of Attaining Buddhahood with This Very Body (Sokushin jōbutsu-gi) plays with the range of meanings in sokushin, which include ‘this body/life’ as well as ‘identical with this body’. Kūkai intimates that Shingon practice not only permits a more rapid or immediate capacity for awakening (in one lifetime) but that it does so because it enables one to discover that the awakened state is actually not found apart from this body because it is ontologically identical with it. This immanence can also be referred to as either ‘original enlightenment’ (hongaku 本覚) or as ‘buddha-nature’. He exhorts practitioners to engage in the Three Secrets practice in order to realize this intimate identity right here in this very body.

3.2 Kūkai’s legacy

The legacies of Kūkai’s lifework are multiple and significant. As one of the leading figures that helped create a strong foundation for Buddhism in Japan’s early Heian period (794–1185), his establishment of the Shingon school was a profound contribution. Some of the key leaders of what is sometimes called a reformation that took place near the end of the Heian period and that set the stage for newly emergent forms of Buddhism in the subsequent Kamakura period (1185–1333) were substantially influenced by the paradigm of esoteric Buddhism he introduced. Nichiren, Hōnen, and Dōgen – who founded, respectively, the immensely influential Nichiren, Pure Land, and Sōtō Zen Buddhist lineages in Japan – all studied esoteric Buddhist practice and theory as ordained monks in the Tendai monastic complex on Mount Hiei (Bielefeldt 1990: 165; Gardiner 1999). While the Tendai tradition developed its own unique and enduring aspects of esoteric Buddhism, its leading monks who forged the school’s growth after the death of the founder Saichō generally emphasized the unity of the Chinese Tiantai teachings Saichō favoured (focusing on interpretations of the Lotus Sutra and writings of the Tiantai founder Zhiyi 智顗, 538–597) with the esoteric teachings they first encountered directly under Kūkai’s tutelage (Gardiner 2019).

What is often called the eventual ‘esotericization’ of Japanese Buddhism was substantially stimulated by contributions from Tendai monks, in particular the brilliant innovator Annen 安然 (841–849?). The Tendai school seems to have flourished institutionally after Saichō’s death more so than did the Shingon school after Kūkai’s. Still, Kūkai’s impact on Saichō’s incorporation of esoteric elements into Tendai practice, and his training of some of Saichō’s prominent disciples, were hugely consequential. Moreover, the Japanese esoteric Buddhist tradition fortified by both Shingon and Tendai forms penetrated into multiple dimensions of Japanese culture. As Carl Bielefeldt writes:

[T]he esoteric tradition itself tended to conceive of Buddhahood in cosmological terms, as the hidden macrocosm of which the human world was the manifest embodiment. An elaborate system of homologies was developed between […] the deities of the Buddhist pantheon and the local gods of Japan, between the virtues of the cosmic Buddha and the psychophysical characteristics of the individual, and so on. The chief means of communication between the two realms was ritual practice – recitation of spells and prayers, performance of mystic gestures, repentance, sacrifice, pilgrimage, and the like – through which the forces of the other realm were contacted and channeled into this world, and the people and places of this world were mystically empowered by (or revealed as) the sacred realities of the Buddha realm […]. This cosmological style of religion is often now held up as one of the key unifying forces of Japanese Buddhism. (Bielefeldt 1990: 390)

Kūkai exhaustively engaged every imaginable opportunity to establish a strong foundation for Shingon practice in Japan. He died relatively young, at 61, yet the second half of his life appears to have been wholly committed to absorbing all that he could from personal relationships, texts, art works, and ritual action, both during his two years in China and for the remainder of his life in Japan in order to offer something of value to others. He returned to Japan with a trove of items, including new texts, paintings, ritual implements, and more, all of which had a huge impact on the development of Japanese Buddhist culture both philosophically and materially (Bogel 2010: 114–117). The widespread celebrations of his achievements as witnessed in the devoted practice of family memorial services in Koyasan and the continued vibrancy of pilgrimages through the circuit of eighty-eight temples on the island of Shikoku are testaments to one of Japan’s most enduring collective cultural memories. Notwithstanding the impact of medieval legends that embellished his biography, such as of his continued physical survival, his completing grand calligraphic works with brushes in both hands and feet and mouth, and the legend that he created the Japanese hiragana syllabary (to name just a few), the well-documented accomplishments of his energetic life are abundant and impressive. It is admittedly difficult to gauge the impact of a systematized theology, but his was embodied in the many concrete ritual performances he and those he trained instituted around the country, rituals that made their way into monastic prayer routines, individual meditations, state ritual, and private memorial services. Over two dozen votive documents exist written by Kūkai on the occasion of a memorial service. Here is an example from one that includes reference to paintings created, scriptures copied, and chants recited for the occasion:

We humbly prayed that the ocean of virtuous power of the Buddhas wash over her spirit so as to purify it; that the mist of delusion be lifted so that she may see Dainichi; and that she come to possess the mirrorlike wisdom that will illuminate the nature of all things. May the marvels of the Dharma and its boundless workings also bring blessings to the relatives who remain, bestowing them with long life and good health […]. May the crown prince, other princes, the state ministers and administrators unite together in wholehearted devotion to faithful service, and may happiness and plenty be secured for all. May the five kinds of heavenly beings and all living things of the ten directions together be gratified in the feast of Dharma that is of a single taste, and may they all move about freely within the palace of ultimate reality. (Gardiner 1999: 158)

The worldview embedded in these rites is one of:

[…] the magnificent compassionate powers of a transcendent Buddha to which all beings living and dead have access through the performance of carefully regulated solemn ceremony […] by all accounts an exceedingly influential one that eventually touched the lives of far more than just the handful of families in the court aristocracy. [Kūkai’s votive documents] demonstrate one very concrete way in which a certain Buddhist model of the world began to take root in Japan. (Gardiner 1999: 156)

Nicholas Morrow Williams (2022: 1) writes that these votive documents Kūkai wrote ‘deploy his vast erudition in both Chinese literature and Esoteric sutras to powerful effect, enacting the triumph over death through the requisite mantras and assistance of the Mahāvairocana Buddha’. His vast erudition extended beyond the literary domain. He was also broadly savvy, possessing highly cultivated social and administrative skills employed to great effect. His consummate ability to attract support for his many projects, to succeed at grafting new ritual forms onto existing paradigms while clarifying a novel and attractive sacred cosmology, and to write masterfully not only in the styles of classical Chinese poetry and literature but also in the language of Buddhist devotion, where his heart clearly lay, was extraordinary. It is hardly a surprise that later generations circulated stories of his supernatural wonder working. He combined erudition with eloquence, and efficiency with poignancy, all as an expression of his passionate calling. His first public statement in the Kan’ensho of his mission to promulgate the new esoteric teachings encapsulates his essentially Buddhist spiritual vision:

All creatures of the six realms and the four types of birth have been our mothers and fathers. Even the insects that fly and crawl all possess buddha-nature. May they all open the undefiled eye [of the Dharma], thereby illumining the source of the three secrets. May they sever the bonds of attachment to existence so that they might delight in the vision of the five wisdoms. (Gardiner 2003: 53)

This passage from a letter written to request help from various acquaintances expresses the quintessentially Mahāyāna Buddhist intention of universal compassion combined with nuggets of esoteric Vajrayāna thought in the ‘three secrets’ and ‘five wisdoms’. Here as elsewhere, Kūkai blends these perspectives seamlessly. And as we have seen, he employs sentences identical to these in his votive ritual documents. His disposition when operating in the mode of religious performance was in complete harmony with his engagements in friendly correspondence. This ability to endow his lifework with unity of purpose was surely a key force that assured an enduring legacy for his vision.

4 Notes on further reading

Yoshito Hakeda’s Kukai: Major Works (1972) remains a solid introduction to his life and includes partial translations of some his best-known writings. Ryūichi Abé’s Kūkai: The Weaving of Mantra (1999) offers the most detailed account of his life and works coupled with an original argument regarding Kūkai’s success at replacing a Confucian paradigm for ritual language with a Buddhist one.

David Gardiner’s Kūkai: Japan’s First Vajrayana Visionary (2024) emphasizes elements central to Kūkai’s project to graft an esoteric Buddhist model of theory and practice onto existing Buddhist institutions, and highlights the philosophical and socially strategic power of his claim that ‘the Buddha’s Dharma body teaches’ (hosshin seppō).

Shingon: Japanese Esoteric Buddhism (1988), written by the Shingon priest and scholar Taiko Yamasaki, provides a thorough traditional exposition of various elements of Shingon history and practice. Thomas Kasulis’ multiple works present keen philosophical analyses of many of Kūkai’s chief theories on language, reality, and practice (see Works Cited list).

Gardiner’s ‘Tantric Buddhism in Japan: Shingon, Tendai and Esotericization of Japanese Buddhism’ (2018) summarizes the topography of esoteric Buddhism’s development in premodern Japan. Geoffrey C. Goble’s Chinese Esoteric Buddhism: Amoghavajra, the Ruling Elite, and the Emergence of a Tradition (2019) treats the rich Chinese context that predated Kūkai by focusing on the tantric master Amoghavajra, whose lifework Kūkai seems to have emulated.

John Krummel’s entry ‘Kūkai’ in the online Stanford Encyclopedia of Philosophy provides excellent detail on doctrines. Philip L. Nicoloff’s Sacred Koyasan: A Pilgrimage to the Mountain Temple of Saint Kobo Daishi and the Great Sun Buddha (2007) gives a detailed portrait of modern Koyasan as a center for monastic life and a pilgrimage destination. And Ian Reader’s Making Pilgrimages: Meaning and Practice in Shikoku (2004) shines a bright anthropological light on contemporary lay Shingon practices.

Attributions

Copyright David L. Gardiner (CC BY-NC)

Figure 1, ‘Bronze statue of Huigo transmitting esoteric teachings to Kūkai’ – photograph courtesy of David L. Gardiner.

Figure 2, ‘Kongōkai (Vajra Realm) mandala’ – public domain, via Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Kongokai.jpg.

Figure 3, ‘Taizōkai (Matrix Realm) mandala’ – public domain, via Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Taizokai.jpg.

Bibliography

  • Further reading

    • Abé, Ryūichi. 1999. Kūkai: The Weaving of Mantra. New York: Columbia University Press.
    • Gardiner, David L. 2018. ‘Tantric Buddhism in Japan: Shingon, Tendai and Esotericization of Japanese Buddhism’, in Encyclopedia of Buddhism. https://doi.org/10.1093/acrefore/9780199340378.013.619
    • Goble, Geoffrey C. 2019. Chinese Esoteric Buddhism: Amoghavajra, the Ruling Elite, and the Emergence of a Tradition. The Sheng Yen Series in Chinese Buddhist Studies. New York: Columbia University Press.
    • Hakeda, Yoshito. 1972. Kukai: Major Works. New York: Columbia University Press.
    • Krummel, John. 2022. ‘Kukai’, Stanford Encyclopedia of Philosophy Edited by Edward N. Zalta and Uri Nodelman. https://plato.stanford.edu/archives/fall2022/entries/kukai/
    • Nicoloff, Philip L. 2007. Sacred Koyasan: A Pilgrimage to the Mountain Temple of Saint Kobo Daishi and the Great Sun Buddha. New York: State University of New York Press.
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