Duli Xingyi 独立性易 （1596-1672, Dokuryū Shōeki, better known perhaps as Ōbaku Dokuryū） went to Japan during the transition between the Ming and Qing dynasties and became a monk. He has been, based on this, regarded as a typical Buddhist according to the existing scholarship. In a series of studies by Takai Kyōko 高井恭子, Duli Xingyi is also thought of as a thinker of the Syncretism of the Three Religions （三教一致）. In the present article, the author investigates the correspondence between Duli Xingyi and Zhu Shunshui 朱舜水 （also known as Zhu Zhiyu 朱之瑜; 1600-1682） stored in the Yanagawa Kobunshokan 柳川古文書館, and explores Zhu Shunshui’s reply to the letter which expresses Duli Xingyi’s opinion about the Syncretism of the Three Religions. The main content of this letter is Zhu Shunshui’s refutation of several arguments of Duli Xingyi. Therefore, this paper first investigates previous studies that regard Duli Xingyi as a thinker of Syncretism of the Three Religions. Further, based on a philological study of Zhu Shunshui’s reply, this paper determines Duli Xingyi’s propositions from Zhu Shunshui’s letter, so as to clarify Duli Xingyi’s criticism about the theory of the Syncretism of the Three Religions.
