Called upon During Japan's Deadliest Recorded Epidemic

Bhaishajyaguru, known in Japan as Yakushi Nyorai, became one of the most heavily invoked Buddhist figures during one of the deadliest disease outbreaks recorded in early Japanese history, the Tenpyo epidemic of 735 to 737, believed by modern epidemiological historians to have been smallpox, which spread from Kyushu and is estimated in some scholarly reconstructions to have killed a substantial share of the entire Japanese population within a few years, including several of the powerful Fujiwara brothers who had dominated the imperial court. The court's documented religious response drew heavily on Buddhist ritual aimed at Yakushi as the Buddha of healing, including the construction and dedication of temples and images specifically to seek his intervention against the disease, part of a broader pattern in which Nara-period Japan responded to plague and disaster through large-scale state-sponsored Buddhist building and ritual projects rather than through medical intervention in any modern sense.

The Yakushiji temple in Nara, whose origins as an imperial vow-temple predate this specific epidemic but whose continued imperial patronage was shaped by the same recurring anxiety about plague and the court's health, remains one of the most historically significant Yakushi-dedicated temples in Japan today. This historical episode illustrates concretely what Bhaishajyaguru's twelve vows regarding illness and healing meant in practice for an early medieval society with no other effective response to a catastrophic epidemic: an entire imperial court turning, in a moment of demographic catastrophe, to the specific Buddha whose defining vows promised exactly the kind of bodily deliverance the era's actual medicine could not provide.