Xuanxuan Qijing Problem 19: White to play and kill
玄玄棋经 · Problem 19 of 347 · Reducing from both sides, then the placement
Black's eye space stretches along the top edge. Narrow it from both ends before playing inside, and notice how few liberties Black's stones have.
How to solve it
Black's eye space runs along the top edge. White narrows it from both ends: A18, answered at A17, and then E19, answered at D19.
White now plays inside at D17 and Black blocks at D18. White's C18 puts Black's stones on the right in atari, so Black has to capture with D16.
That leaves Black no time to defend at B18. White plays there and Black cannot make two eyes. Sensei's Library notes that this only works because Black's stones have no outside liberties.
Main line
- 1. White A18
- 2. Black A17
- 3. White E19
- 4. Black D19
- 5. White D17
- 6. Black D18
- 7. White C18
- 8. Black D16
- 9. White B18
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.