:: Igo Hatsuyôron 120 (2021)

Variations of Our Solution (IIIb)

Tricking KataGo (Triple-Ko)

VAR (C) (A) (.2)

: ( 222aa)
White occupies the guzumi point.

She will gain two points overall, compared to the solution, wherein Black played the guzumi much earlier.

This White move is the proof that Black should not delay the guzumi as long as KataGo's 2019 special network seemed to "believe".

: ( A 222ao)
Black gives atari at White's two stones in the lower left.

However, he should have inserted Michael Redmond's kikashi in the bamboo joint before, denying White four points of additional territory in the upper right corner.

:
White's peep at the upper edge stops Black from playing the aforementioned kikashi.

:
Black is unable to connect his hasami-tsuke stone, and so continues with the Main Semeai at the left.

If he connected at the upper edge, he would fall below the Punishment Semeai Liberty Level.

///:

This is the position at White's decision point.

Currently, Black is par with the Punishment Semeai Liberty Level, so he is able to finish the following endgame sequences in gote.

: ( 143 222fw)
We start our presentation with White's "classical" atari at Black's single stone at the top.
Please note that the borders of White's territory in the upper left are solidly closed, and that the endgame at the left side of the board now would be played after the dissolving of the hanezeki, which ends with White having sente. Therefore, it does not matter any longer if it is White who has the last valuable move, as Black does not have any use for his sente left.

It is well known that choosing Yamada Shinji's tsuke at would be better for White.

: (152 222gb ; A 222gc ; 147 222gd)
White continues with the hane at the upper edge, threatening to reduce Black's territory in the upper left corner.

Alternatively, she might consider continuing with at the lower edge, or playing the wedge of at the top.

Playing the "silent" connection of , however, would be one point worse overall.

Please note that Black will play at in the right centre in the Capture Variation only.

Capture Variation:

Compared to the super²ordinate variation ...

  • Black's cumulated gain in the upper left corner is one point.
  • White's cumulated gain in the lower left is two points.
  • Black destroyed one point of White's territory in the centre.

In total, gains and losses compensate for each other.

White + 2 => White + 2

Semeai Variation:

Compared to the super²ordinate variation ...

  • Black's cumulated gain in the upper left corner is one point.
  • White's cumulated gain in the lower left is two points.
  • Black captured an additional White stone at the left, so gaining two points.

In total, White lost one point.

Black + 3 => Black + 4

Copyright © 2021 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

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