佛教傳入日本一千三百餘年，至明治維新前夕，幾乎成為日本國教。在這段過程中，聖武天皇發布的〈建國分寺之詔〉，為日本佛教的發展，在制度上提供了「政教一致」最關鍵的基礎。然而學界對於這份詔書發布的契機與背後動機的研究，長期以來主要的論證，集中在聖武天皇天平元年至十年間，日本發生史上罕見的一連串地震、旱災、蟲災、疫病這一點。而上古日本文明初開，各種典章制度未備，尤其是修史事業，尚在學步隋唐階段，以致於詔書上下文脈所顯示的時、地、事，與正史《續日本紀》收錄此詔書的紀年位置，有所落差，這點更是各家說法爭執所在。本文在前賢的研究基礎上，另將聖武天皇「未婚皇女立太子」的政治事件導入，論證出詔書本文擬定的時間點，與其背後的政治考量。

By the eve of the Meiji Restoration, Buddhism had been playing a role tantamount to national religion for over 1300 years. "The Edict for Establishing Kokubunji"〈建國分寺之詔〉 decreed by Shoumu Tennou (聖武天皇,700-756) had played a critical role in the development of Buddhism in Japan, since the Edict supplied an institutional basis for the development of Buddhism from the very beginning. For a long time, when discussing the impact and incentive of this Edict, scholars focused on the coincidence of a series of plagues, draughts, and earthquakes during a brief 3-year period (735-737) that had even led to the deaths of 4 top officials in Shoumu Tennou Regime. This article endeavors to show that the most critical cause of the decree of the Edict lay in the crisis brought by the anti-traditional designation of the unmarried Princess Abe (阿倍內親王) as the sole successor to Shoumu Tennou's position.

國分寺；聖武天皇；光明皇后；阿倍內親王立太子；長屋王事件；龍女成佛

Japan Buddhism；Shoumu Tennou；Kokubunji；Nagayaou Incident