is the only move to live.
must be answered by
- and certainly not
or
. One suffers from shortage of liberties, and the other lets Black kill at
.
looks like making two eyes, but due to the descent at
, Black can play
. Now White can only live by a ko at
.
(Note that at a is wrong - see below.)
If White throws in with ,
takes one of the kos. Now if White plays at a or b, Black fills with
, holding White to one eye.
(After and
elsewhere)
If White later takes the ko back with ,
takes the other ko. Now if White connects at
, Black connects at
and kills.