Xuanxuan Qijing Problem 58: Black to play and make a ko
玄玄棋经 · Problem 58 of 347 · Placement and sacrifice
White has space on the top but no secure eye. Play inside first, and be ready to add a second stone where it looks as if it will simply be captured.
How to solve it
This problem is titled 'Moon Palace' (月宮勢). Black attacks White's group on the top with the placement at J18. White's K18 is a good defence, and Black's L18 is the brilliant follow-up.
White's best answer is J19. Black plays K17, and the result is a ko.
If White resists with M18 instead, Black plays K17. White captures a stone with L19, Black plays K16, and after White's H18, Black's J17 and White's J19, Black's N18 kills the main body of the group.
If White answers at K17, Black plays H18. After White's H19, Black's E19, White's J19 and Black's F19, White captures two stones with J17, but Black's M18 kills.
Main line
- 1. Black J18
- 2. White K18
- 3. Black L18
- 4. White J19
- 5. Black K17
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.