Sunday Problem #6

Published 12 Jul 2020 by antti (last edited 3 Sep 2020)

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

Black to play in both problems.

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 the focus, it is correct for White to make a placement at 2 in response to black 1. Subsequently, the position develops into a two-step kō for the black group’s life.
As the black group is not easy to finish off, and White risks losing two stones of his own, KataGo’s recommended sequence in the previous diagram makes sense.
When Black has an extra outer liberty, she can form two eyes with 1. White’s best attempt is probably to try to remove the black eye to the right with 2–4, but White finds this impossible due to his shortage of liberties.

Comments (1)

antti wrote 2 years ago:

Solutions added.