Confused: increases the liberties to three for the white group; and after
Black needs an additional approach move at
before being able to play at a.
Variation: black might play trying to start a ko, but white still wins the capturing race (
at
,
at a).
Variation: black might try to escape to the right. In that case white can stop him with the following sequence. A potential cut at a could be easily fended off by playing at b and putting the black group into atari.
If Black is allowed to play at , the white group dies. It doesn't matter whether White played at
or at a, b, c or d.