:: Igo Hatsuyôron 120 (2021)

Variations of Our Solution (IIIb)

Tricking KataGo (Triple-Ko)

VAR (C) (A) (.2) (.2) (.1)

(.2)

: ( 222dm)
White pushes at the left edge, threatening Black's stones above.

:
Black encloses White's stones in the corner by descending to the left edge.

Giving atari at in the corner immediately will result in a change in the order of moves.
Black might also insert the exchange of , at the top before. White will avoid unnecessary complications by simply choosing the block, as this exchange does not affect the liberty count in the Main Semeai.

:
White connects her single stone in the upper right, simply continuing with the Main Semeai.
Please note that his move also erases all Black ambitions to start a semeai with her centre group.

There is no need for White to complicate the matter by starting a ko fight by giving atari at .
Quite surprisingly, capturing the nakade with is not available as a ko threat here. Black will simply capture at . Thereafter, White is unable to invest a move at the left, in order to generate independent life for her large group, as Black will start - and win - a semeai with her centre group.

:
Black has to capture White's stones in the corner sooner or later.
However, he loses a decisive tempo in the Main Semeai by this need.

:
The Main Semeai continues.

///:

This is the position just before White's decision point. Black's large group at the right as seven liberties left (6 x , 162).

:
White occupies another liberty of Black's group, so choosing the Semeai Variation.

Capturing the hanezeki's tail, so entering the Capture Variation, is out of the question here.
Black's right-hand group would survive. He has gained massively in the upper left corner already, and would win the game by about 15 points.

:
Black has to connect the hanezeki's tail now.

:
The known sequence continues for a little while.

:
But now White attacks in the lower right, utilising the fact that Black has one Main Semeai Liberty less than "usual".

:
White captures Black's three stones in the corner.

:
Black gives atari at White's group at the left.

He is unable to play the oki at , as White would give atari at his connected tail group with .

:
White brings all of her hanezeki groups to independent life, so realising a gain of about 55 points in that corner (compared to the "usual" result of the Semeai Variation).

White will win the game by about 40 points.

Copyright © 2021 Thomas Redecker.

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