Xuanxuan Qijing Problem 72: White to play and make a ko
玄玄棋经 · Problem 72 of 347 · Placement inside the corner
Black's corner has room, but the stones along the top are thin. Start with a stone inside, on the second line, and keep attacking from within.
How to solve it
White attacks the corner with the placement at D18. Black blocks at D19, White plays C19 and Black connects at E19.
White's B18 comes next. If Black plays A18, White plays C18, and after Black's B19 White captures with A19: the corner is a ko.
If Black connects at C18 instead, White plays A17. Black captures a stone with B19, but White's A18 kills.
Main line
- 1. White D18
- 2. Black D19
- 3. White C19
- 4. Black E19
- 5. White B18
- 6. Black A18
- 7. White C18
- 8. Black B19
- 9. White A19
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.