Sunday Problem #12

Published 23 Aug 2020 by antti (last edited 3 Sep 2020)

This problem is from another of my favorite tsumego collections, or ‘Collection of tsumego masterpieces’ by Sekiyama Riichi, Sekiyama Toshio, and Sekiyama Toshimichi.

Sekiyama Riichi is famous for winning the first Hon’inbō tournament in 1941; Sekiyama Toshio is his son; and Sekiyama Toshimichi is Toshio’s son. As a fun trivia, the ‘Ri’ in Riichi is written with the same character () as the ‘Toshi’ in his child’s and grandchild’s names.

Black to play.

Black has very little to work with in this problem. The upper-side white group is unkillable, so the best Black can try is to make use of its shape weaknesses to gain leverage for his own group.
The white
a stones form the weakest link in White’s shape, and the black attachment of 1 is the best way to make use of them.
If White decides to resist as hard as he can, then the moves from 2 to 10 follow: finally, a two-step ko for the life of both the black and white groups results.
Instead of 2, White could also play at 3, in which case both the black and white groups live.

Comments (1)

antti wrote 1 year, 1 month ago:

Solution added.