The status of the Black group is that the group is already dead.
The main line is the descent at , which looks like it can live with a straight four. But with the correct sequence from
to
, Black is caught with a shortage of liberties, and is unable to play at a.
If , then
occupies the vital point. Later, if Black plays at a, then White can play elsewhere.
If here, then
plays at the same point.
tries to make a ko, but the placement at
followed by the descent at
is a standard tesuji.
The hane at is interesting. If
is played wrongly, it can lead to an two step ko. With the correct move, Black dies.
is a careless move, which gives
a chance to live by an two step ko.
makes an eye in the corner, but
destroys the eye on the edge.
Playing at the 1-2 point does not work here, makes
and
miai for the kill.