Superko Puzzle 2

  Difficulty: Advanced   Keywords: Ko, Tactics, Rules

See also RulesBeast1.

Another Superko puzzle. (this is copied from the two eyes can die page)

As an aside to the discussion above, there are some situations involving superko where two-eyed groups may be sacrificed.

W to play. Chinese rules, 0 komi  

In this position white can use the sending two returning one to create a superko problem for black.


W5 circled, B6 = Pass, W7= W1  

Should black be naive: After playing through the cycle once black cannot capture again after W7. After black passes again, white will capture the upper left group, winning the game. In order to win, black must give up a different two-eyed group.


W5 circled  

After playing B6 the lower right group is dead, but black will have no more restrictions from superko and will win the game 41 to 40.

RobertJasiek: Presumably Francois Lorraine discovered the eye filling tesuji first for a position with a 1-eye-flaw. In general such positions are extremely rare on the 19x19 (fewer than 1 in 10 million games?) because they require non-existence of ordinary tenukis in territory. For small boards, the probability is a bit higher.

Bill: Back to the drawing board, I think.

Final score, all points filled  

Black has 35 points, White has 44.

Superko Puzzle 2 last edited by PJTraill on December 28, 2018 - 20:12
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