The Ōsu Library (Ōsu Bunko 大須文庫) at Shinpukuji 真福寺 in Nagoya is famous of having many good medieval manuscripts, not a few of which have relations with Zen Buddhism. They are now being published in the series Chūsei Zenseki sōkan 中世禅籍叢刊 (A series of Zen texts from medieval Japan), 12 vols. Some of them are works of Yōsai 栄西 (or Eisai) and one of them belongs to the Daruma lineage founded by Nōnin 能忍. They also contain transcripts of lectures by Enni 円爾 at Tōfukuji 東福寺 and by Chikotsu Daie 癡兀大慧, one of the disciples of Enni. In this article, I examine those Zen texts and try to make clear the formation of Zen Buddhism in Japan.
