Sunday Problem #52

Celebrating one year of Sunday Problems!

This problem is from Kōno Rin 9p’s Twitter.

Black to play.

Solution
Solution (1)
If White gets to play at 1, no combination of two black moves can kill his group, and so we can quickly figure out that black 1 is the only possible starting move.
If White challenges Black with 2, …

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NGD Online League Turns One; League Price Changes

It has soon been exactly one year since we started the current ngd online league – which itself was based on the Nordic Go Academy program we held in 2011–2015.

At the time of writing, we have done 601 game reviews. 325 of these are by yours truly, with Oscar being the second most prolific teacher at 158 reviews. In …

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Sunday Problem #51

This is technically an original problem by me, inspired by the recent ngd league game between Sandmann and le_4TC. However, the shape quickly develops into something that also exists in classical tsumego collections.

Black to play.

Hint

Try to avoid kō.

Solution
Failure
Black’s block of 1 is obvious, and so the question is what to do after white …

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Oscar on Sacrificing Stones

Streamed on Twitch on May 22, 2021.


Sunday Problem #50

This is a variant of the infamous carpenter’s square that comes up from time to time in games.

This is a problem for high dan amateur players, so for everybody else I have added a small spoiler that tells the end status of the problem, without actually showing any moves.

Black to play.

Spoiler

Black can kill unconditionally.

Solution
Failure …

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KataGo’s ‘Perfect Selfplay’ (2)

Similarly to this post from a few weeks ago, this is a commentary on KataGo’s self-played game with a high number of playouts, ranging from 100,000 to 1,000,000. This commentary was sponsored by @Marissa on the Leela Zero and Friends Discord channel.

See full post to read kifu annotations!


Sunday Problem #49

This is an original problem by me, based on a shape that occurred in a league game between Soeren and Lebertran. Subscribers of the 2021 April league can view the game here.

Black to play.

Solution
The problem
This problem is mainly about how to turn ‘a’ and ‘b’ into two eyes for Black. Normally, both of they …

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Sunday Problem #48

Like Problem #12, this is from the Collection of Tsumego Masterpieces by Sekiyamas Riichi, Toshio, and Toshimichi. This time, Black has to try to make life in a very cramped corner setting.

Black to play.

Solution
Failure (1)
Black’s connection of 1 creates a challenging subproblem, but ultimately it is wrong. White’s sharp attack of 2–10 kills Black unconditionally. …

Read the full post here!


Oscar on Games of Fujisawa Shūkō 9p

Streamed on Twitch on May 1, 2021.