Four Go houses
In the history of Go in Japan, the four Go houses were four major schools of Go instituted, supported, and controlled by the state, at the beginning of the Tokugawa shogunate. At roughly the same time shogi was organised into three houses. Here "house" implies an institution run on the recognised lines of the iemoto system common in all Japanese traditional arts. In particular, the house head had, in three of the four cases, a name handed down: Inoue Inseki, Yasui Senkaku, Hayashi Monnyu. References to these names, therefore, mean to the contemporary head of the house.
The four houses were the Honinbo, Hayashi, Inoue, and Yasui. They were originally designed to be on a par with each other, and competed in the official castle games called oshirogo.
The houses
Hon'inbō
The Hon'inbō house was easily the strongest school of Go for most of its existence. It was established in 1612 and survived until 1940.Upon the closure of the school, the title Hon'inbō came to be used for the winner of the Honinbo Tournament, which is now an annual professional Go event in Japan. It is run under the titleholder system, meaning that at any given time there is a player who can use the title Hon'inbō. It is customary for Japanese players to take a special personal name as Hon'inbō, a unique feature of this title; for example Takagawa Kaku held the title for nine years, and during this time was referred to as Hon'inbō Shukaku. Players of other nationalities by custom do not adopt a special name but do use the Hon'inbō title.
Hon'inbō Shūsai sold his title to the Japan Go Association before retiring in 1936, effectively ending the Hon'inbō line.
All three of the "Go saints" came from this school— Dosaku, Shusaku, and Jowa. Most of the holders of the Meijin title were also from this house. Another prominent member was Hon'inbō Shūsaku, who was heir to become head of the school, but died of cholera before officially becoming Hon'inbō.
Hayashi
The Hayashi house was one of the four Go houses of Edo period Japan. It was in effect the junior partner in the system of Go schools, never producing a Meijin player. Always an ally of the Honinbo school, for traditional reasons, it didn't survive to the end of the period as truly independent. Its headship went to Honinbo Shuei, and when he became also Honinbo head, it was de facto merged into the Honinbos.From the second head onwards, the head of the house when playing was known as Hayashi Monnyū.
Inoue
The Inoue house was one of the four Go houses, the state-supported schools for the game of Go in Japan during the Edo period.The numbering of the heads of the house is that introduced by Inoue Genan Inseki, at the start of the nineteenth century, and including Nakamura Doseki for reasons of prestige. During their playing careers all the heads, apart from Doseki, were called Inoue Inseki. For reasons of convenience the retirement or posthumous names are used, in the style Inoue Genkaku Inseki with the personal part of the name interposed. Variant names abound.
Yasui
The Yasui house was one of the four Schools of Go which were officially recognized during the Edo period of Japanese history.Each of the four schools were founded by Tokugawa Ieyasu in 1612.
The house had one Meijin, in Yasui Sanchi. It has been commented that the general style of play tended to the pragmatic, rather than the artistic way.
From 1737 to the present, the current head of the Yasui house has been known as Senkaku. The retirement or posthumous names are listed here.