The history of Go 03 Go in the middle ages
(the Kamakura and Muromachi periods)

The spread of Go
The Kamakura (1192-1333) and Muromachi (1338-1573) periods were a time when power shifted from the court nobility to the military class, and when culture was more widely diffused around the different regions of Japan. This also overlapped with the spread of Buddhism.

Go, which had been popular among the court nobility and the aristocracy, now spread became popular among the educated classes, that is, the military class and the Buddhist priesthood. It also gradually seeped down to the peasantry and the mercantile class.
The Great Buddha of Kamakura

In 1199, Genson wrote the oldest surviving Japanese Go book, called eThe Rules of Go, in which he explained the tactics and etiquette of Go and the rules.

There is a record of a game played in 1253 between Nichiren, founder of the Nichiren sect of Buddhism, and his disciple Kisshomaru (also known as Nichiro). This is said to be the oldest suriving record of a Go game, but it is not known if it is genuine. However, there seems to be no doubt that Nichiren played Go, as there is a reference to it in a book of sermons written in his own hand.

In the same year, a rules problem (concerning double ko) is said to have arisen in a game between two Buddhist priests.

Contemporary literary works, such as the Azuma Kagami, the Taiheiki (both actually works of history) and Yoshida Kenkofs essay collection Tsurezuregusa also contain references to Go.
Yoshida Kenko

Around 1530, a 20-volume work, the Shiqinglu, was compiled by Lin Yinglong. It includes some 384 Go diagrams composed by the Japanese monk Kyochu. It is not known who Kyochu was, but it is thought that at this time Japanese Go had reached the same level as in China.