BQM 8
Problem
Killing Sequence 1 (The Easy One)
Looks are very deceptive... It looks as if Black is alive. However, the hane at , and , kill unconditionally.
Killing Sequence 2 (The Harder One)
The placement at works, too. The aji caused by becomes apparent and Black is now unconditionally dead.
If Black connects at , White can play the hane at to kill. After and , Black can't play at a because of shortage of liberties. So if he captures the two stones, White kills him at a.
...White continues his atari sequence, and occupies the vital point of . Black dies with a bulky five shape.
Capturing the white stone at is also useless. White can cut at , , and : and Black is again given the death sentence. If plays at , and White can play atari at , reverting to Variation 1.
Maybe this variation is not needed? In response to , White cuts at and plays atari at , capturing the stones.
Other Variations
We shall now consider Black's other answers to the hane (the marked stone). is a possible move, but reduces Black to a bulky five. If Black plays , White plays at ; and a and b are miai.
Well, must never be played at a, or else Black plays atari on three stones at c, White d, and makes two eyes.
See also: