White might try to play hane at in order to play
in sente. If black gives the usual answer, a and b are miai for life. If
is answered with
white would have a chance to escape at
.The correct answer is to keep following on the second line with
or throw-in at
to reduce eyespace.
One of the simplest refutation to the hane of is
. After
and
, it is not possible for Black to play at a.