Xutang Zhiyu 虚堂智愚 (1185–1269) was a Chan monk of the Linji school 臨済宗 representative of the late period of the southern Song. His lineage was transmitted and extended in Japan and is linked nowadays to the Japanese Rinzai. Materials like Logia of the Master Xutang and Records of the life of Xutang are preserved so that we can know his biographical dates. One of the salient features of his biography is that Xutang was deeply committed to the monks of Caotong school 曹洞宗. During the late Southern Song period, the Caotong school decayed so that we do not know in what state it was, but it seems that it gave importance to sitting meditation (zuochan) qualified as silent enlightenment. After becoming a monk, Xutang first trained earnestly under the direction of Changweng Rujing 長翁如浄 (1162–1227) and exchanged dialogues with him in the Jingci Temple 浄慈寺 in Hangzhou 杭州. Rujing was a Chan monk of the Caotong tradition and is well known as the master of Dōgen 道元 (1200–1253). Xutang maintained very deep relations with Chan Caotong monks, even after becoming a superior of Jilinqi 棘林杞 (?–1258), Duanpengyuan 短蓬遠 (?–1247) and Donggu Miaoguang 東谷妙光 (?–1253). A disciple of Dōgen, Kangan Giin 寒巌義尹 (1217–1300), travelled to China carrying the Extended records of Eiheiji Temple 永平寺 of Dōgen, and a disciple of Rujing, Wuwai Yiyuan 無外義遠 (?–1266), choose excerpts of this work to compile a collection in one volume, the Logia of Zen Master Dōgen of Eiheiji. At that time, Giin went to the Jingci Temple and obtained a postface of Xutang who was the superior of this temple. By reading the logia of Dōgen, Xutang praised the personality of Dōgen who surpassed his masters. We can see in this way that the biography of Xutang is related with a large number of Chan monks of the Caotong school, and that the activities and facts concerning Xutang have an importance that we cannot neglect in any effort to discover the reality of the Caotong school at this time.
