Xuanxuan Qijing Problem 49: Black to play and kill
玄玄棋经 · Problem 49 of 347 · Under the stones
Nine white stones need two eyes on the top edge. The first move is not hard to find; the third is. Read White's squeeze to its very end: what can be played where captured stones used to be?
How to solve it
This problem is titled 'Nine Old Men Playing Easily' (九老優遊勢): nine white stones sit comfortably along the top. Black's D18 is the only way to start, and White answers at C18.
Black's third move, B19, is the important one. Playing C19 there instead lets White make a ko with B19.
A long forced sequence follows. After White's F18, Black's B18, White's E19 and Black's A16, White captures two stones with D19 and Black plays G19. White is planning a squeeze: White's A17, Black's capture at A19, White's A17 again, Black's A18, White's C19 and Black's A15, and then White captures six stones with A17.
But Black plays back under the stones at B17, and White is left without two eyes.
Main line
- 1. Black D18
- 2. White C18
- 3. Black B19
- 4. White F18
- 5. Black B18
- 6. White E19
- 7. Black A16
- 8. White D19
- 9. Black G19
- 10. White A17
- 11. Black A19
- 12. White A17
- 13. Black A18
- 14. White C19
- 15. Black A15
- 16. White A17
- 17. 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.