Honinbo Dosaku (本因坊道策, Yamazaki Sanjiro, Hon'inbō Dōsaku, 1645-1702) was a Japanese professional go player from the Edo period. He became head of the Honinbo house in 1677 and Meijin Godokoro in 1678. He helped establish the professional ranking system and regularized the Castle Game system. His strength and pioneering theoretical work laid the foundations for the future prosperity of the Honinbo house and go. He was later conferred the title of Go Saint.
Born in Iwami, Shimane prefecture in 1645 under the name Yamazaki Sanjiro, he learned go at the age of seven, and became disciple of Honinbo Doetsu at the age of 15 or 16. At this point he acquired the name Dosaku. When Doetsu retired in 1677, Dosaku became the 4th head of the Honinbo house and was recommend for position of Meijin Godokoro. Prior to this, the Yasui house, under the leadership of Yasui II Sanchi (Meijin Godokoro from 1668-76), were the Honinbos' main rival. However, in a unique event Dosaku was appointed Meijin Godokoro in 1678 without a single objection from the other Houses.
At this time, there were no other players who could hold their own against Dosaku. Nevertheless, it was only after becoming Meijin Godokoro that his skills would truly blossom. He became the master tactician in an era filled with strong tactical fighters, and could control the flow of a game through skillful sacrifices and brilliant tesujis. Tied to these features was his pioneering work in a kind of analysis called 'tewari,' innovation in the skill & strategy of amashi, and development of opening theory through the use of his famous three-space low pincer. Once incorporated, his strength was said have become about two-stones stronger than his nearest rivals.
Unfortunately, Dosaku appears to have never had the opportunity to demonstrate his full, mature strength in an even game. This meant that he was playing a large number of handicap games and rarely as Black. Additionally, his only two losses in the Castle Games appear to have been contrived for a one-point loss. Dosetsu was noted as saying that if he would take White in 100 games against Dosaku, he would lose all 100. Future generations would say he had developed the strength of a 13-dan (at the time each two rank difference meant a one stone handicap difference (source?)).
Honinbo Dosaku was known for instructing a wide range of influential pupils, including a group known as the Five Tigers (Hoshiai Hasseki, Inoue Dosetsu Inseki, Kumagai Honseki, Ogawa Doteki & Sakugen). He was even said to have had over 30-pupils living in at once.
Several of his star pupils also predeceased him: Hoshiai Hasseki (age 24), Kumagai Honseki (23), Ogawa Doteki (21) & Sakugen (25), probably from tuberculosis.
List of Pupils:
- Hayashi Bokunyu Monnyu
- Honinbo Dochi
- Horibe Innyu
- Hoshiai Hasseki
- Inoue Dosetsu Inseki
- Inoue Sakuun Inseki
- Inoue Yuseki
- Kumagai Honseki
- Ogawa Doteki
|1668-07-10||Yasui Chitetsu||Go Review Nov. 1970|
|1670-05-06||Kikugawa Yuseki||Masterpieces of Handicap Go Vol. 2, Redmond's Reviews Episode 2|
|1670-10-31||YasuiChitetsu||Redmond's Reviews Episode 4|
|1670-11-29||Yasui Santetsu II||Go Review Summer 1974, Redmond's Reviews Episode 24|
|1674-08-30||Yasui Chitetsu||Go World Iss. 11|
|1678-10-17||Fukuo Genko?||Masterpieces of Handicap Go Vol. 2|
|1681-11-10||Honinbo Doetsu||Go World Iss. 11|
|1682-05-24||Peichin Hamahika||Go World Iss. 18|
|1682-12||Ogawa Doteki||Appreciating Famous Games, Go World Iss. 5|
|1684-01-05||Yasui Shunchi||Appreciating Famous Games|
|1687-12-12||Ogawa Doteki||Go World Iss. 12|
|1688-1702||Hinaya Rippo? ||Masterpieces of Handicap Go Vol. 1|
 Hinaya Ryuho, painter. French Wikipedia has an article on him under the name Nonoguchi Ryuho. Rippo seems to be a misreading.
About 150 of his games are known today.
- SGFs can be found at http://homepages.cwi.nl/~aeb/go/games/games/Dosaku/
or in the archive http://homepages.cwi.nl/~aeb/go/games/dosaku.tgz.
- Japanese site Go-yu-an has replayable complete games in two parts: Part 1 and Part 2 (Java required)
- (Chinese) Honinbo Dosaku - Complete Game Collection (2009)
- Japanese 1933 edition of Complete Games (117 games, no commentaries) is available at the Japanese National Diet Library:
- In 2003, Nihon Kiin published "Goshin Dosaku" (碁神道策) containing 153 games of his, incorporating latest study. Annotated by Fukui Masaaki. ISBN-13 : 978-4818205277
 Yasui II Sanchi feigned illness in order to avoid attending the meeting to elect Dosaku. Had Sanchi attended, then previous touchy relations with the Honinbos' would have caused pressure for him to challenge Dosaku's application, whom he knew would likely accept and win.
- Honinbo Dosaku was in the first group to be initiated into the Nihon Kiin Hall of Fame (the others were: Honinbo Sansa, Honinbo Shusaku and Tokugawa Ieyasu).
- Many of his games were only rediscovered in the 1990s.
- Partial commented games & kifu woven into a story can be found here: http://www.kyoto.zaq.ne.jp/momoyama/DosakuIndex.html. (Some of the historical information is innaccurate.)