:: Igo Hatsuyôron 120 (2021)

Variations of Our Solution (IIIb)

Tricking KataGo (Triple-Ko)

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

(.4)

: ( 222go)
White pushes from below into Black's upper left corner.

This push is preferred by KataGo (2020) from a reverse komi = -9 on.

White does not lose a Main Semeai Liberty by this move, as an approach-move liberty is created in Black's upper left corner.

For a more detailed analysis, please see the comparable position after the "early" capture of the nakade ( 222gn).

:
Black is forced to intercept at the left edge.

He is unable to capture White's stones in the corner unconditionally by descending to , instead, as this would cost him a decisive tempo in the Main Semeai. Thereafter, White would win the Punishment Semeai.

:
White's hane into the corner creates the ko shape.


Ko: ;

:
Here, with the nakade still on the board, White has only one ko threat in the lower left corner. Thus, she starts the ko fight by cutting in the left centre.

:
Black utilises his kikashi in the hanezeki as ko threats, as there will be no semeai with White's centre group here.

Please note that we will not colour the edges of the boards during the ko fight.


Ko: ;

:
White has only one ko threat in the lower left corner.

Please note that there are no follow-up threats in this area (e.g. or ), due to the current shortage of liberties of her three marked stones at the left edge.

:
Black threatens to reduce White's bottom group to only one eye.

:
It is best for White to connect the ko, so ending the fight in the upper left corner.

:
Black reduces White's group to only one eye, so enforcing the later capture of the hanezeki's tail.

:
White starts with the endgame, also saving her two stones in the upper right.

:
White connects, as there are no larger endgame points on the board remaining.

:
Eventually, White captures the hanezeki's tail.
Her bottom group will lose the semeai with Black's large group at the right anyway.

:
Black recaptures, as usual.

:
The endgame continues.

...

...

Capture Variation:

Compared to the superordinate variation ...

  • White's cumulated gain in the upper left corner is 17 points.
  • White got an additional four points of territory at the top.
  • Black's cumulated gain in the lower left corner is two points.
  • White captured an additional two Black stones at the bottom, so gaining two points.
  • Black did not capture White's two stones in the lower left, so losing four points.
  • White's cumulated loss in the nakade area is six points.
  • Black's cumulated gain at the right is seven points.

In total, White gained twelve points.

Jigo => White + 12

Copyright © 2021 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

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