:: Igo Hatsuyôron 120 (2019)

Variations of Our Solution (III)

VAR

: ( 548ke)
Black further resists by solidly connecting, but he will be unable to win any of the ensuing ko fights in the top left corner.

:
White gives atari in the corner.

: (A 548keb)
Instead of capturing White's single stone, Black might try the counter-atari of .

: (110 548kec)
Black's attachment denies White access to the corner.

Black might want to cut immediately in the centre, with a move at , but will not succeed either.

: (113 548ked)
Alternatively, White has the option to answer at in the corner, letting Black connect his troops thereafter.

:
This hane prepares the ground for the forthcoming ko at the upper edge.

:
White's ko threat utilises Black's "new" weakness in the centre.

:
Black connects, making the ko a direct one for both sides.

:
Another White ko threat in the centre.

:
Black threatens to live in the top right by capturing White's stones below. However, the value of this move (if regarded as a valid ko threat) is much too small.

:
White can ignore , because she will be able to kill Black's group in the upper left corner, and so get independent live for her large group at the left edge.

Alternatively, White could answer Black's ko threat by blocking at , gaining one decisive Main Semeai Liberty.
As long as White has not connected at in the lower left, Black must not play moves that result in losing him a Main Semeai Liberty. On the other hand, every White Main Semeai move is a valid ko threat for her.

:
Black secures life for his large group at the top right.

:
However, White kills Black's top left corner in return.

:
Black, for his part, cannot kill White's top right corner.
Even if he could, he would not win the game, just because White does not need to capture the hanezeki's tail.

White wins the game by a large margin.

Even if the Hanezeki Exchange (, ) had not been played, Black would be short of ko threats.
White also has at least three threats at the points of in the centre. Additionally, capturing the nakade and / or the hanezeki's tail, with moves at , will be a source of a large number of White ko threats.
On the other hand, Black moves at any of the points of are no valid ko threats, as White intends to capture the tail anyway. And she will do so in sente.

Copyright © 2020 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

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