We consider the position as shown in this diagram. The focus is on the upper left corner.
The hane-connect is a large sente endgame play for Black.[1] The question is, how should White play at the corner if there are also large endgame plays elsewhere?
White would be reluctant to play the hane-connect at and
, because it is a gote move.
The descent at is an improvement, because it threatens to enter the corner, but this may not be good enough.
The reason is that if there are more urgent plays elsewhere, can tenuki. While
and
can enter Black's corner,
can tenuki one more time. So Black gets sente for two times, and the value of White's moves are no so great anymore.
The real endgame tesuji for White is to play the hane at and another hane at
.
If blocks, then
is an atari, which is sente for White.
On the other hand, if choose to tenuki, then connection cum atari at
is much more severe, compared to having the
stone at a. Here
threatens to capture three Black stones, and this may also have life and death implications depending on the configuration on the right side since it also destroys Black's eye in the corner.
Author:
[1]
elsewhere.
Bill: Since we do not know what the surroundings are, we cannot be sure that the hane-tsugi, -
, is sente.
The point is that White's play in the corner is quite large, perhaps bigger than Black's threat with .