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Honinbo Dosaku
Full name	Honinbo Dosaku
Kanji	本因坊道策
Date of birth	1645
Place of birth	, Japan
Date of death	1702
Place of death	, Japan
Teacher	Honinbo Doetsu
Rank	9 dan

Honinbo Dosaku (本因坊道策, 1645-1702) was a professional go player.

Contents 1 Biography 2 Becoming Meijin by fiat 3 Games 4 Theoretician 5 Pupils 6 External links 7 Notes

[edit] Biography

Dosaku was one of the greatest go players in history. He was born in the Iwami province of Japan and studied Go in the Honinbo school, becoming Meijin at a very young age.

Dosaku was the fourth Honinbo, fourth Meijin and a go saint (Kisei) by the time he was 23. He started to learn go at 7. Dosaku was so strong by the time he was in his early 20's that even if someone played the first move, he would always win. Rumors were that he was two stones stronger than any other go player. This was due to his deep thinking and next-level tactics. Players today can thank him for founding what is used today as modern opening strategy.

[edit] Becoming Meijin by fiat

Only a short time after receiving the Head of the Honinbo school he was given the post of Meijin in recognition of his unrivaled strength. On one account, this controversial appointment (which deprived Yasui Sanchi of his official positions) was handled by the jisha bugyo by summoning a meeting of all concerned parties, including the shogidokoro Ohashi Sokei. Sanchi did not attend, and the change of Meijin-godokoro was agreed nem. con. The ground for this decision was the match of 20 games played between Honinbo Doetsu and Sanchi, for which Dosaku probably acted as Doetsu's second on adjournments.^[1]

[edit] Games

By the time he was 32, he was already head of the Honinbo school and placed at the top of the official hierarchy. It has been suggested that the true level of his playing strength was never really tested, given the distance between him and his nearest rivals. The evidence of his contributions is in the legacy of games, known to us by the kifu records.

Two of his famous games are the 1683 defeat by one point in a two-stone game (his 'life-time masterpiece') and the 1670 castle go game when his opponent opened at tengen, the central point, which was a victory. These were both against members of the Yasui house. Over 150 games of his are known.

[edit] Theoretician

Dosaku is also well remembered for his contributions to go theory. He took advantage of overconcentration also known as korigatachi, making that henceforth one of the key theoretical errors that players avoided. Tewari analysis, a systematic if rather tricky tool of analysis of efficiency of sequences, is also attributed to him; as is the strategy of amashi.

In playing Peichin Hamahika from the Ryukyu Islands, in 1682, he gave a practical demonstration of his theories, winning easily when giving a four-stone handicap. This game is a textbook piece and is still frequently cited. (The first game he won by 14; the second game on the same day was also recorded and he lost by a small margin, which may naturally mean that he had nothing to prove and was being diplomatic.)

In the field of joseki, he innovated with the three-point low pincer, a more strategic play than the two-point low pincer favoured in particular by the players of the Yasui house.

[edit] Pupils

He taught Ogawa Doteki, Sayama Sakugen, Hoshiai Hasseki, Kumagaya Honseki, and Kuwabara Dosetsu. All but one died young, in their early twenties, and the Honinbo house faced a period of rebuilding.^[2] Dosetsu became the Inoue house head. The young Honinbo Dochi carried on the tradition.

[edit] External links

• The story of Dosaku (including games)
• Sensei's Library article

[edit] Notes

1. ^ All this as is in Go Monthly Review 1963/6 p.42. All the traditional stories are somewhat slanted, typically in favour of the Honinbo side.
2. ^ Go Monthly Review 1963/8, p.48

Preceded by Yasui Sanchi	Meijin 1677–1702	Succeeded by Inoue Dosetsu Inseki
Preceded by Honinbo Doetsu	Honinbo 1677–1702	Succeeded by Honinbo Dochi