tderz: just arrived here via the thumbnails!
Which are great.
This problem comprises a timing aspect.
If White ever wanted to play here, she has to play
now,
i.e. before an A-B exchange.
Not claiming that this is the start of a correct solution.
tderz: if White thus already had exchanged
for
,
and then played
, Black's natural answer
would ensure life for Black and kill White's marked stones.
tderz: the idea would be that after
, if Black A, then b-c-damezumari.
However, this is flawed, as Black will never reply to
by A, rather live directly with D.
tderz:
-
will not harm and suddenly
looks like a vital point
which only has to be verified for liberties.
tderz: White has stunning 7 liberties, which is a lot! One can do a lot in the meantime ...
tderz: if
here, White cuts at
, Black cannot atari at B,
and the two corner stones provide the 2nd eye ..
unkx80: For a while, I was trying to figure out what happens when Black resists with
and
. But
is a tesuji that works for this problem despite the cutting point at
.
tderz: whow!
and
are really strong moves, as is kb's
above.
tderz: For completeness: the outside hane is the weakest line of response.
White can now play A or B and win by 7 to 3+sente liberties.