Xuanxuan Qijing Problem 15: Black to play and kill
玄玄棋经 · Problem 15 of 347 · Throw-in and bent four in the corner
White's eye space looks large, but two of the white stones are only loosely joined. Sacrifice a stone there first, then reduce the corner from the inside.
How to solve it
The black stone already on the first line at F19 is what makes this work. Black starts with the throw-in at D18. White has to capture with C18, and Black then plays inside at B19.
If White blocks at B18, Black plays E19, and after White's A16 the placement at A18 leaves White with a bent four in the corner, which is dead.
If White descends to A16 first, Black plays A18. C19 and E19 are then miai, and White cannot make two eyes either way.
Main line
- 1. Black D18
- 2. White C18
- 3. Black B19
- 4. White B18
- 5. Black E19
- 6. White A16
- 7. Black A18
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.