Showing posts tagged: sunday-problem


Sunday Problem #13

This problem is from the Japanese tsumego collection, or ‘Collection of Shūkō’s tsumego masterpieces’ by Fujisawa Hideyuki (whose first name can also be read as ‘Shūkō’).

I have received some feedback that the Sunday problems have been too difficult, so this week I tried to pick a slightly easier problem. Still, in my opinion it is not fun if …

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Sunday Problem #12

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 …

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Sunday Problem #11

This is a slightly modified version of a problem that came up in the league game between bellicose and yosai.

Black to play.

Solution
Solution
Black 1 is the key point. White 2 is forced, but Black can then form the necessary eye space with the descent of 3. After 4–5, white 2 is captured in an oiotoshi, …

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Sunday Problem #10

This is the cover problem of Mateusz Surma’s tsumego book series You won’t get dumber while thinking.

Composing go problems is tough work. It can take hours just to come up with one good problem and, once you publish it, the problems themselves are not even copyright-protected – only the problem collection and the answers. This is why I …

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Sunday Problem #9

Like Sunday Problem #8, this is also from Guanzi Pu.

Black to play.

Solution
Correct solution
Black’s 2-1 placement of 1 is the key to solving this problem. 2–6 are White’s correct resistance, and the result is a kō for White’s life.
Black fails
If Black starts with the hane of 1, white 2 lives unconditionally.

Sunday Problem #8

This problem is from Guanzi Pu – possibly my favourite of the classic problem collections thanks to its varied and relatively difficult problems.

While a (most likely illegal) pdf version of the book been posted around on Western go websites, its solutions often seem to be wrong. I would instead recommend interested players to invest in a six-volume physical copy, …

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Sunday Problem #7

Black to play.

Solution
The result may look like a seki at first glance, but White is actually dead in a bulky five shape.

Sunday Problem #6

This Sunday we have a set of two problems. What difference does Black’s extra liberty make?

Black to play in both problems.

Solution
KataGo’s solution
KataGo thinks the sequence from 1–5 is generally best for both sides: Black lives in gote while White makes a profit in the corner.
Tsumego solution
In tsumego terms, i.e., when life or death is …

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Sunday Problem #5

Black to play.

Solution
Black’s sacrifice technique with 3 and 5 is the key. This provides the two other black stones an extra liberty that allows Black to win a local capturing race with 7–11.

Sunday Problem #4

This problem was created by Lee Eodeokdung 1p. He showed to me at the European Go Congress 2017, and it quickly became one of my favourite tsumego.

Black to play.

Solution
White 2 is the strongest resistance to Black’s attachment of 1. Following...
...after black 7, White dies in a double ko. This is still better for White than dying unconditionally, as the group will supply infinite ko threats.