Koshu City Katsunuma Library in Yamanashi Prefecture is located in a gentle alluvial fan covered with vineyards. It was the residence of “Iwasaki clan” and “Katsunuma clan,” both descendants of “Kaigenji clan” just as Takeda Shingen, a distinguished warlord. The area also flourished as “Katsunuma-juku,” a post town along Koshu Highway. It was also in Katsunuma that growth of “Koshu grape,” an indigenous species of Yamanashi Prefecture that originally came from the continent, was discovered. During the Meiji era, two local youths, Masanari Takano and Ryuken Tsuchiya, traveled to France to learn wine making under the order of the prefecture. It is a land where history of “grapes and wine” continues to the present. There are two possible origins of Koshu grape: “grape legend of Daizenji-Temple” and “legend of Amemiya Kageyu.”