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.
Here "house" implies an institution run on the recognised lines of the iemoto system common in all Japanese traditional arts.
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.
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.
They were also nominally Buddhist institutions, with the Honinbo and Hayashi aligned with the Nichiren sect, and the Inoue and Yasui with the Jodo Shu.
[clarification needed] Some outward forms only persisted of that connection, with the oshirogo games being played in Buddhist dress and with shaven heads; the stylish Ota Yuzo was given a waiver of the obligation since he was proud of his hair.
[3] At least, in theory, matters on succession in the houses were subject to the authority of the jisha bugyo, an official regulating religious establishment.
Nominations as heir, typically within the iemoto system of the best disciple, who might not be a natural son but in effect adopted, were supposed to be made official.
More creditably, since the Meijin title could only be awarded to the undisputed master player of the time, there were occasions when it was withheld from two candidates whose merit was very close (an example was Genjo and Chitoku, around 1810–1820).
The mode of teaching, by apprenticeship, brought a consistent and high level of play (though some say the standard sagged in the eighteenth century).