Xuanxuan Qijing Problem 24: Black to play and make a ko
玄玄棋经 · Problem 24 of 347 · Placement on the 1-2 point
The side offers no eyes, so look to the corner. Which point there gives Black the most to work with?
How to solve it
Black's group has no room for two eyes on the side, so the fight is in the corner. Black plays A18, the 1-2 point.
White's strongest answer is B18. Black plays B19, White plays C19, and Black's B17 makes a ko for the life of the group.
If White answers at B19 instead, Black plays B18. After White's C19 and Black's B16, White's D19 is met by F19 and Black lives without a ko.
Main line
- 1. Black A18
- 2. White B18
- 3. Black B19
- 4. White C19
- 5. Black B17
Solution checked against Sensei's Library.
Play it out on the board
Place the stones yourself and see the refutation when you miss. All the Xuanxuan Qijing problems as quick lessons.