The four houses
During this time, the strongest Go players in Japan were usually part of an organized school or ‘house’, which they represented when they played.
The four most successful and powerful houses were the Honinbo, Yasui, Inoue and Hayashi houses.
The members of the houses were like a family (iemoto system), even though they weren’t always blood relatives.
Dosaku was the 4th head of the Honinbo house, but at the time when this game was played he was still in his twenties and was the heir of the 3rd Honinbo, Doetsu.
However, later in his life Dosaku became the Honinbo and was also appointed as Meijin – an official position which was reserved for the strongest Go player in Japan.
He’s also credited with having invented the concept of tewari analysis and innovating in many other areas, such as the effective use of three-space pincers.
Yasui Chitetsu was the third head of the Yasui house. He wasn’t as famous as Dosaku, but he was probably the Yasui at the time when this game was played.
In the period just before Dosaku, the Yasui’s had been the strongest house for awhile, even though the Honinbo house was the oldest and most prestigious.
The Castle Games
Castle games, like this one, were played in the presence of the shogun. They were the most important games for Japanese Go players during this period.
There was no komi at the time when this game was played, so black gained more of an advantage from playing first and white had to play more aggressively to catch up.