The term honji suijaku or honchi suijaku (本地垂迹) in Japanese religious terminology refers to a theory widely accepted until the Meiji period according to which Indian Buddhist deities choose to appear in Japan as native kami to more easily convert and save the Japanese.
[4] During the late Kamakura period it was proposed that the kami were the original deities and the buddhas their manifestations (see the Inverted honji suijaku section below).
[5] Honji suijaku has often been seen as similar to interpretatio Romana, a mode of comparison promoted in antiquity by scholars such as Tacitus who argued that barbarian gods were just the foreign manifestations of Roman or Greek deities.
[6] The term honji suijaku itself is an example of the Japanese practice of Yojijukugo, a four-character combination of phrases which can be read literally or idiomatically.
[1] A different but equivalent explanation, the idea that Buddhist deities choose not to show themselves as they are, but manifest themselves as kami, was expressed in a poetic form with the expression wakō dōjin (和光同塵), which meant that to assist sentient beings, deities "dimmed their radiance and became identical to the dust of the profane world.
[1] The frequency of the practice is attested by the kakebotoke (懸仏), or "hanging buddhas," found in many large shrines—metal mirrors that carry on the front the effigy of the shrine's kami and on the rear the relative Buddhist deity.
[1] As the theory gradually spread around the country, the concept of gongen ("provisional manifestation", defined as a Buddha that chooses to appear to the Japanese as a kami[3]) evolved.
[1] Under the influence of Tendai Buddhism and Shugendō, the gongen concept was adapted, for example, to religious beliefs tied to Mount Iwaki, a volcano, so that female kami Kuniyasutamahime became associated with Jūichimen Kannon Bosatsu (eleven-faced Kannon), kami Ōkuninushi with Yakushi Nyorai, and Kunitokotachi no Mikoto with Amida Nyorai.
[9] The honji suijaku paradigm remained a defining feature of Japanese religious life up to the end of the Edo period.
[1] The theory was ultimately beneficial to the kami, which went from being considered unilluminated outsiders to actual forms assumed by important deities.
[1] The ultimate expression of this shift is Ryōbu Shintō, in which Buddhist deities and kami are indivisible and equivalent like the two sides of a coin.
[10] Buddhism, for example, proscribed fishing, hunting, and agriculture because they involved the killing of living beings (insects, moles and the like in the case of farming), but the honji suijaku concept permitted people to void the prohibition.
[10] It was often said that temple lands in Japan were local emanations of Buddhist paradises or that an artisan's work was one with the sacred actions of an Indian Buddha.
[14] The dominant interpretation of the buddha-kami relationship came to be questioned by what modern scholars call the inverted honji suijaku (反本地垂迹, han honji suijaku) or shinpon butsujaku (神本仏迹) paradigm, a theology that reversed the original theory and gave the most importance to the kami.