In the past research, it has been shown that in the Sōtō sect from the Muromachi period until the beginning of the Edo period emphasis shifted to Kōan Zen depending on so-called Shōmono, such as Gorokushō and Daigo. All the Shōmono known until today were formed later than the 15th century, and after the death of Keizan Jōkin (1264–1325), that is after the latter half of the 14th century, many questions remain concerning the tendencies of thought in such literature.
The Shōbōgenzō bussogosoku is a document of the later 14th century in which are extracted the main points from Keizan Jōkin’s Denkōroku. The original sources were in a mixed writing style of Japanese and Chinese, but expressed now all in Chinese. In this paper, the style and content of the Shōbōgenzō bussogosoku is carefully examined, and it is shown that this document is to be placed among the trailblazing Shōmono post-dating the 15th century. Furthermore, it is argued that the original source of the Shōbōgenzō bussogosoku, the Denkōroku, is the first step in the genre of Shōmono texts.