It also refers to a traditional Japanese title given to the strongest player of the day during the Edo period.
The title of "Meijin" derives from a game played by the first Hon'inbō, Sansa.
An onlooker (no less than Japanese warlord Oda Nobunaga) watched him play a particularly brilliant move and exclaimed "Meijin!"
Sansa, besides being Nobunaga's Go tutor, also taught Toyotomi Hideyoshi, who, after taking control, established Sansa as Godokoro, roughly meaning "Head of the Government Go Bureau."
The Meijin title came to be greatly prized by all of the most promising Go prodigies of the age, freed from the cares of everyday life by the government stipends coming from the Go Bureau.
After the Meiji Revolution, the four houses fell into disrepair due to the lack of government stipends.