<論説>山城国海印三昧寺の創立

Abstract

九世紀前半に、東大寺の華厳僧道雄が山城国乙訓郡に建てた海印三昧寺は、これまでは、当該期の御願寺や華厳宗を論じる素材としてのみ扱われてきた。しかし、その実像を正面から分析した研究は多くない。本稿では同寺の史資料を精査し、その歴史像を立体的に復元することを目指した。海印寺は、日本華厳宗の伝統教学を否定して革新教学を創始し、宗の再生を図るための拠点として創立された。同寺は人跡未踏の山奥に立つ山林寺院であったが、その立地は伝統教学から物理的に距離を取ることを目的としていた。創立当初には文徳天皇との人格的紐帯を命綱としたが、清和朝以降、天皇家との関係は薄れていく。それでも、国土保安の祈願所かつ東大寺華厳宗の母胎として、一一世紀中葉までは存在感を保持していた。古代海印寺の生きざまを追究した本研究は、平安時代の華厳宗発達史論や寺院制度史論などに、新たな論点を提供するものでもある。

Kaiin Zanmaiji Temple 海印三昧寺 was built in the first half of the 9th century on Mount Konokamiyama 木上山 in Otokuni-gun, Yamashiro Province by the Kegon monk Dōō 道雄 of Tōdaiji Temple. Kaiin Zanmaiji has been the subject of many studies in the past when discussing goganji 御願寺 (imperial vow temples) and the Kegon sect. However, there have been no studies that have directly addressed its history. This paper attempts to provide an examination of the temple that will serve as a first step for further research. Kaiinji Temple 海印寺 has been understood in the past as a Kegon temple with multi-sectarian with multi-scholastic traditions. However, a close reading of the dajōkanpu (order of the Council of State) dated the 22ⁿᵈ day of the third month of Kashō 4 (851), which is a basic historical record of Kaiinji, makes clear that the common view is incorrect. Rather, it should be understood as a site of practice for the specialized study of Kegon doctrine alone. Dōō requested the Imperial Court to designate Kaiinji, which he had built, a jōgakuji 定額寺 (government-sanctioned temple) and to appoint a kugyō-bettō 公卿別当 (chief administrator appointed from high-ranking court nobles) and nenbundosha 年分度者 (yearly ordinands). The purpose of this request was to establish a system for the perpetuation of his original doctrinal views and practice at Kaiinji. At that time, the Japanese Kegon sect was on the verge of decline, both politically and scholastically, having been swallowed up by other sects. Dōō saw that the cause of the decline lay in traditional doctrine, and he sought to revitalize the Kegon sect by implementing drastic doctrinal reforms. Kaiinji was built and maintained as a base for this purpose. In other words, Kaiinji was the stronghold of the Dōō school of the Kegon sect and a bridgehead for the Kegon reform movement. Researchers have sought to discover the site of ancient Kaiinji in the area around Jakushōin Temple 寂照院, located in Myōjinmae, Oku-Kaiinji, Nagaokakyō City in Kyoto Prefecture. However, there is no historical or archaeological evidence to suggest that ancient Kaiinji was located in the Jakushōin area. In fact, historically speaking, ancient Kaiinji should be located on Mount Konokamiyama, which rises to the west of Jakushōin. I have concluded, based on several field surveys and Heian-period landscape reconstructions, that ancient Kaiinji temple existed in the Matsutakeo area of the mountain. The site was an unexplored area deep in the mountain in pre-modern times. The reason Dōō built Kaiinji deep in the mountain was to physically remove the monks of Kaiinji from the traditional doctrines to achieve doctrinal reform. On the other hand, Kaiinji was also granted various benefits by the Imperial Court. A detailed analysis of these favors reveals that Kaiinji had a personal relationship with the emperor as an individual. Particularly prominent was Kaiinji's relationship with Emperor Montoku 文徳天皇. For example, immediately after Montoku's accession to the throne, Dōō and his family received special treatment. It is certain that there were personal ties between Dōō and Emperor Montoku. The day of the annual installment of ordinands at Kaiinji Temple itself was set on the national anniversary of Emperor Montoku's death, and it can be assumed that the monks of Kaiinji were responsible for protecting Montoku. It should also be noted that the institution of the yearly ordinands at Kaiinji was the day after the first anniversary of the death of Emperor Montoku's father, Emperor Ninmyō 仁明天皇. For the Montoku line of the monarchy, protecting Kaiinji had the advantage of providing religious protection for the new emperor as his reign was about to begin in earnest. However, Kaiinji's survival strategy was not built solely on the protection of the emperor; the protection of Buddhism and the security of the nation were also important components. Moreover, when Kaiinji lost its link to royal authority with the deaths of Dōō and Montoku, it abandoned the path of maintaining its power by clinging to its link with the emperor. Instead, Kaiinji sought its raison d'etre in national security and the protection of Buddhism, especially the latter. In other words, Kaiinji could no longer rise to the status of goganji. Nevertheless, Kaiinji contributed greatly to the revival and development of the Kegon sect at Tōdaiji. In the middle of the 10th century, Kochi 光 智, a follower of Dōō, founded Sonshōin 尊勝院 at Tōdaiji as a new center of Kegon Buddhism. This was proof that the Dōō school based at Kaiinji had finally succeeded in putting down roots within Tōdaiji. Thereafter, Kaiinji Temple maintained its existence as a valuable training base for supplying full-fledged Kegon monks to Sonshōin. However, it seems that this value was gradually lost as Sonshōin became more and more prosperous. By the 12th century, Kaiinji was completely incorporated into Sonshōin.