Sunday Problem #47

Published 25 Apr 2021 by antti (last edited 2 May 2021)

It looks like this white corner group is difficult to capture unconditionally, but there is a surprisingly clean sequence hiding in plain sight.

Black to play.

Solution
Failure (1)
Simply turning with black 1 is not enough. White claims the key point of 2, and then for example black 3 and 5 get refuted by White’s 4 and 6. White is alive.
Failure (2)
The combination of black 1, 3, and 5 is a bit more like it, and, up to 10, manages to create a kō for White’s group when Black next captures at 7. However, this is still not the best Black can do.
Solution (1)
Black’s more straightforward sequence of 1–5 is correct in this problem. This is because Black can then play 7 and unleash her key tesuji of 9, which has recently been dubbed the ‘liver blow’ on the ngd Discord server. (The name derives from the fact that 9 could locally also be called a ‘belly attachment’, but with its follow-up of 11 and 13 in the following diagram it is decidedly more powerful.)
Solution (2)
Finally, White can try to resist with 12 and 14, but after black 15 the corner ends in a dead bent four shape.

Comments (1)


antti wrote 6 days, 23 hours ago:

Solution added. This was a hard one!