torazu sanmoku

  Difficulty: Expert   Keywords: Rules, Go term

Chinese: 不提三目 (bu4 ti2 san1 mu4)
Japanese: 取らず三目 (torazu sanmoku)
Korean: -

[Diagram]
Torazu sanmoku  

Torazu sanmoku = Three points without capturing.

The traditional Japanese ruling (attributed to Honinbo Shuwa) was that this corner position was worth 3 points for Black at the end, without his having to capture the marked white stones. However...


[Diagram]
After B capture  

... the Japanese '89 rules make this seki if it is left on the board at the end of the game. Therefore Black should capture before the game ends (See diagram; B2 may be delayed). The name is misleading under current Japanese rules and the same is true for another similar shape, Torazu Gomoku.

[Diagram]
(continued)  

Black got 2 points in Gote (White may play at a instead of W5 and fight the ko to reduce 1 point).

Mathematical Go defends the 3-point ruling in terms of combinatorial game theory. See derivation.

Chen Zuyuan? claims that this rule is inconsistent with modern Japanese scoring, but is based upon stone scoring.

' ' However, the traditional Japanese Go rules call it “three points without capturing”, which means there are 3 points for Black. This obviously does not comply with present Japanese rules. But by the idea of "each side", even if White moves first and there are "equal stones", the result is still 3 points for White. This shows that the original Japanese rules are based on the concept of "each side", and "three points without capturing" is its legacy.' ' [ext] New In Go

(By "each side" Chen means that each player plays the same number of stones.)

Note that the CGT derivation is in terms of territory scoring, not stone scoring. See Discussion.


Subpages

Discussion

Derivation


See also:


torazu sanmoku last edited by hnishy on June 30, 2018 - 10:46
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