Ŭijŏk’s Posalkyebonso 菩薩戒本疏 is commented using the Yogācārabhūmi 瑜伽師地論 by his contemporary, Sŭngjang 勝莊. But, Ŭijŏk’s ideas of the Religious Precepts and Buddha-nature are different from those of Sŭngjang. Therefore, it is unreasonable to discuss the relationship of influence. His approach is similar to those of Wŏnhyo 元暁 and Fazang 法蔵 in that he used the Yogācārabhūmi to consider the Bodhisattva violation of the precepts as no offence. In particular, his approach is very similar to Fazang’s thinking on the Bodhisattva-culpability. His relationship with Zhiyi 智顗 is likewise discussed because he quoted Zhiyi’s commentary under an alternate name, ‘Gushu 古疏’.
This study examines the thinking on the Religious Precepts in Ŭijŏk’s Posalkyebonso. In doing so, it examines the similarities and differences with post-Zhiyi commentaries. Then, the stude confirms Ŭijŏk’s influence on Táehyŏn 太賢, and reveals the relationship between the two on the Brahmajāla-sūtra.