Abstract
The sutra mound built by the nun Hoyaku at Oku-no-In on Mt. Koya has three main characteristics: (1) for a sutra mound built by a woman it contains extremely high quality objects; (2) the stated strong desire that, under the divine protection of Kukai, it would encounter the future coming of the Maitreya and be placed under the grace of the Buddha; and (3) the existence of the philosophy of nirvana. The author considers Hoyaku as Chugu Atsuko Naishinno, wife of the Emperor Horikawa, and argues that the mound was built as a memorial service for the Emperor, the sutras being buried shortly before the death of the empress. It can be presumed that this rare support for Maitreya beliefs derived from the particular ardent belief of those who cherished the memory of the emperor that they would be able to meet him again in the event of the coming of the Maitreya. The empress was a devout Buddhist who also accepted popular Buddhist beliefs.
It is rare that the identity of a person who erected a sutra mound is known; in many cases we also have no clues as to the beliefs of that person. On the other hand, there are a few cases where sutra mounds are known to have been built by individuals such as Fujiwara-no-Michinaga, Fujiwara-no-Moromichi and the retired emperor Shirakawa for whom there is a massive quantity of available information. If we consider Hoyaku's Oku-no-In sutra mound as having been built by the Horikawa Empress, then we have another such example of an identifiable mound. The custom of erecting sutra mounds began with Michinaga burying sutras on Mt. Kinpu. These four individuals all belonged to the highest level of society. Michinaga lived a few decades earlier, but the other three were all closely related. Political power was concentrated in the hands of Michinaga and retired emperor Shirakawa who consequently held practical, worldly beliefs; in contrast, the Horikawa Empress clearly had beliefs that negated the mundane and it is interesting that such popular ideas should have also spread to the highest echelons of society.
The priest Saichu who practiced on Mt. Hiei emphasized that everyone has the potential to achieve Buddhahood. Michinaga's great-grandfather and grandfather had used their marital relations with the imperial family to strengthen their political power. At the same time, their financial support for Mt. Hiei increased their influence over the priests there. The political power of these Sekkanke Regents reached its peak during the time of Michinaga who built sutra mounds based on the beliefs found on Mt. Hiei. The Regents were opposed by the imperial family who took back power during the time of the Emperor Go-Sanjo. In the following generation, retired emperor Shirakawa followed Michinaga's custom and buried sutras on Mt. Kinpu; he later became passionate about Kumano shrine and his grandson Toba also placed sutras in that shrine.
The Pure Land sect and nirvana beliefs that supported the construction of sutra mounds were popular movements that grew mainly through the proselytism of hijiri (holy men). In the Kyoto area, these hijiri were based in the holy parts of Rakuhoku and traveled between the believers in Kyoto and the main temples of Mt. Hiei and the southern capital. Within this wide area of operations, there are also examples of hijiri traveling between Kyoto and shoen estates and between different estates owned by the same landowner. These beliefs and practices spread both geographically and socially and gradually developed into Kamakura Buddhism.
