Xuanxuan Qijing Problem 77: Black to play and win the capturing race
玄玄棋经 · Problem 77 of 347 · Two-stone sacrifice to shorten liberties
Black's two stones in the middle are caught between two white groups. Before filling liberties on the left, make the white group on the right uncomfortable. It is worth giving up two stones.
How to solve it
Black's stones at G17 and G18 are cut off between two white groups, and a direct race looks lost. Black starts with the cut at K18. White gives atari with J18, Black extends to K19 and White blocks at J19. These two stones cannot be saved, but they have done their work.
Black now turns to the left: F19, answered at E19, then G19, answered at E18, and finally E16. The white stones on the left are down to two liberties.
White has no good move. Capturing the two stones costs a move, and Black uses it to give atari and capture the white stones on the left first. If White instead tries to fill a liberty of Black's group from the right, White's own group there runs out of liberties, because of the two sacrificed stones.
Main line
- 1. Black K18
- 2. White J18
- 3. Black K19
- 4. White J19
- 5. Black F19
- 6. White E19
- 7. Black G19
- 8. White E18
- 9. Black E16
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.