Tantric Buddhism in Japan: Shingon, Tendai, and the Esotericization of Japanese Buddhisms
Authors: Gardiner David L. 
Published: August 2018

From the early 9th century a new orientation emerged in Japanese Buddhism that emphasized specific Tantric, or Vajrayāna characteristics of both doctrine and practice. While elements of the Vajrayāna (vehicle of the diamond/thunderbolt) Buddhist traditions of mature Indian Mahāyāna Buddhism were present in Japan in the 8th century, it was only in the new Buddhist schools of Tendai and Shingon that related practices recently imported from China were specifically identified as “esoteric” in nature and as different from the other schools of Buddhism that were newly designated as “exoteric” by these schools. The first to promote this distinction was the monk Kūkai, founder of the Shingon school. His contemporary Saichō, who founded the Tendai school, placed himself and several of his disciples under Kūkai’s tutelage to learn what the latter had brought back from an intensive study period in China. Yet Saichō’s approach was to place the esoteric teachings and practices on a par with his Tendai teachings, derived primarily from the Chinese Tiantai school. His difference from Kūkai on this matter drove both an eventual end to their cooperative relationship and, after Saichō’s death, innovations by Tendai school exegetes that aimed to reconcile the differences. The combined force of Tendai esotericism (Taimitsu) and Shingon esotericism (Tōmitsu) impacted greatly the development of subsequent centuries of Japanese Buddhism. The three major schools of Buddhism that dominated during the Nara period (710–794)—Sanron, Hossō, and Kegon—all incorporated esoteric elements into their practice during the Heian period (794–1185). By the time of the Kamakura period (1185–1333), when the new forms of Zen, pure land, and Nichiren Buddhism emerged, the esoteric paradigm was so ingrained in Japanese Buddhist thought that even though esoteric practice was at times explicitly criticized by the new schools, much of its worldview was implicitly affirmed.

Central to Japanese esoteric Buddhism is the understanding that through engaging in the ritual practices of reciting mantra, practicing symbolic hand gestures known as mudra, and imagining one’s self and all beings as being intrinsically awakened (one meaning of the term mandala), one can achieve the enlightened stage of buddhahood within one lifetime. These three are called the “practices of the three mysteries” (sanmitsu gyō三密業), through which a practitioner is able to unite with the enlightened energy of the cosmic buddha’s body, speech, and mind. More than anything else, it was this cosmological framework that influenced the development of many later Buddhist practices. Fundamental to this model was the affirmation that every living being is intrinsically endowed with the latent qualities of buddhahood. This concept of “original enlightenment” (hongaku本覚) framed an immanental, holistic vision that recognized the real presence of nirvāṇa (freedom, liberation) in the midst of one’s experience of saṃsāra (the cyclic world of ignorant suffering). The unfolding of various doctrinal and ritual means of articulating and verifying a practitioner’s intrinsic state of enlightenment spurred novel theological systems, artistic creativity of many forms, as well as sociopolitical opportunities for aristocrats who sought to invoke the buddha’s power for various mundane needs. Tendai and Shingon monks alike contributed to this growth in a myriad of ways.