Kozanji is a Soto Zen temple founded in 1327, whose Buddha hall of 1320 is Japan's oldest surviving Zen-style structure and a National Treasure. In December 1864, Takasugi Shinsaku raised an army of 84 here in the Kozanji Uprising, a turning point toward the Meiji Restoration.

The Buddha hall of Kozanji is said to have been constructed in 1320, and it survives today as the oldest existing example of Zen-style (karayo) architecture in Japan, designated as a National Treasure. The temple itself was founded in 1327 by the Soto Zen monk Koan Genjaku. During the medieval perio…