Sunday Problem #65

Published 29 Aug 2021 by antti (last edited 11 Sep 2021)

This is an easier classic problem to counterweight the recent difficult problems. While the solution sequence is straightforward, it is however still quite long and makes for good visualisation training.

Black to play.

Solution (1)
Pretty much the only thing Black can try in this problem is the 1–3 squeeze. Following . . .
Solution (2)
. . . after White connects with 4, Black attacks White’s eyes from the side with 5. White 9 next fails to black 6, so White can only block at 6 himself; but then Black forms an eye in the corner with 7 and 9. As White will now never be able to play at ‘a’, his group ends up captured.

Comments (2)

sig wrote 2 weeks, 4 days ago:

Is the best line atari-take-atari-cover-hane O19? Seems white gets to ”escape” to the side of the diagram with P19-R19-N19 because black must fill S19 instead of M19, so white gets to jump to L19. If hypothetically there were live white stones left of K19, white would be out.

antti wrote 2 weeks, 2 days ago:

Solution added.

As sig says, if White happened to have a stone at j19, his group might be able to run out. With no support there, however, the group has no way to survive.