<論説>即位の変容と律令天皇制

Abstract

皇位継承儀礼において、ある時点を皇位継承時点として意識し、空位を徹底的に避けるようになるのは、律令文書行政が整備された大宝〜養老年間以降のことである。これは、八世紀の天皇が律令文書行政の最高決裁者で、他者との権限差が明確であったことを反映し、皇位継承時点がその転換点として重要な意義を持つと同時に、文書行政の停滞を招く空位を徹底的に回避した結果である。皇位継承儀礼の中で、皇位継承時点と空位が律令制本来の意味を失い、形骸化していく過程を指標として、天皇が律令制本来の唯一性・専行性を失い、天皇権力の構造が変化していく過程を論じるのが本稿の試みである。

In this study I have tried to reexamine the [role of the] emperor in the ritsuryo system and the changes affecting it by focusing on the changes over time in the moment one became an emperor and vacancies on the throne in the ritual protocol of imperial succession. In the imperial succession prior to the ritsuryo system, it is difficult to specify the exact moment when someone became an emperor. And, although the throne was at times vacant, the duration was shortened as the members of the royal family served in place of the emperor in an effort to avoid such vacancies, However, under the ritsuryo system, the moment that someone became an emperor was specified, the abdication and the accession to the throne were conducted on the same day from the eighth century, and vacancies were assiduously avoided. This was due to the fact the emperor in the ritsuryo system had ultimate decision-making authority within the bureaucratic titsuryo administration, and the moment that one became an emperor became a critical turning point that clearly distinguished imperial authority from that of others and a vacancy on the throne came to mean a cease in the operation of bureaucratic administration of the state. Therefore, the emperors of the eighth century were in an entirely unique position within the ritsuryo bureaucratic adminjstration, and the original character of the ritsuryo system can be judged to have been vigorous. However, the emperor, as what might be termed a single organ of the ritsuiryo state, was restricted, vacancies on the throne were not permitted, and imperial succession was carried on by abdication. The unique character of emperor in the original ritsuryo system was lost, however, with the changes in the form of government at the end of the eighth century, and the discrepancy between the authority of the emperor and the crown prince also disappeared. On the other hand, in the eighth century, the ritual protocol of abdication had not yet been established, and a contradiction was created when an abdicated emperor and the reigning emperor both tried to exercise sovereignty because the former emperor's sovereignty had not been clearly abandoned. However, this contradiction was resolved from the time of the abdication of Emperor Saga, who clearly relinquished sovereignty. Reflecting this change in the emperor's sovereignty, a clear distinction was made from the ninth century onward in the ritual protocol of imperial succession between abdication or imperial funerary rites on the one hand and the accession to the throne on the other, and the moment that one became an emperor and a vacancy on the throne lost their original meanings within the original ritsuryo system. They came to be valued as merely formalized, ritual protocol.