<論説>平安時代の皇太子在所と宮都

Abstract

本稿では、平安期の皇太子在所の所在地を明らかにし、それを通して政治形態や宮都の変化を考察した。当初東宮であった皇太子在所は、一○世紀には内裏後宮へと移ったが、在所が宮城内(天皇宮内) に置かれるということは皇太子個々の事情によらない原則として維持されていた。ところが、一○世紀末以降、里内裏使用時には、天皇との血縁関係や母親在所との関係をはじめ、外戚や院等との諸関係により在所が定められ、天皇とは必ずしも同所ではなくなった。更に、一一世紀後期にはこの変化は平安宮内裏にも及び、天皇が内裏に居住しても皇太子は必ずしも内裏に居住しなくなった。里第居住は皇太子の個人的諸関係が体現され、強化される居住形態であり、それは政治形態にも影響を与えたと考える。また、一一世紀後期の皇太子在所の変化は平安宮の意義の相対化、律令的都城の変質の一側面を示すものでもあった。

This monograph explores the political significance of changes in the location of dwellings for crown princes and the geography of court and capital. Crown princes initially resided in their own specially designated quarters (togu 東宮) located within the larger palace compound. In the tenth century, however, This residence was permanently moved inside the emperor's palace (dairi 内裏), even though, the crown prince continued dwelling in the larger palace compound as before, irrespective of the identity of the crown prince. From the late tenth century downword, however, the emperor tended to abandon residing in the 'official' palace, choosing instead to dwell in 'provisional' palaces (sato dairi 里内裏). The dwellings of crown princes were not always located in 'provisional' palaces, and were instead designated on the basis of relations with the emperor, retired emperors, the mother of the crown prince, or other kinship ties. From the late eleventh century onward, crown princes no longer invariably lived in the emperor's dairi compound, even at times when the emperor continued to reside there. Thus, the designation of the dwelling of the crown prince served to strengthen the ties of crown princes, and to highlight their political importance. To conclude, the eleventh century changes in the residences of crown princes reflects a relative weakening of the central palace, and represents a further crumbling of the rigid, geometric geography of the ancient (ritsuryo) capital.