:: Igo Hatsuyôron 120 (2021)

Variations of Our Solution (Ib)

KataGo's 2021 Solution

VAR (.3) (.3)

: ( 58by)
White continues with the Main Semeai at the left edge.

:
We will follow the course of the superordinate variation for a while.

...

: ( B 58ce)
Black plays the same protective move in the lower left corner as in the superordinate variation.

However, Black would benefit by one point in the Semeai Variation, if he chose the descent to for defending his lower left corner.

As a matter of course, Black's best option here would be the block at at the upper edge, resulting in the same final scores as with Our Solution.

:
White starts the reduction of Black's upper left corner.

:
Both sides follow the course of the superordinate variation.

; :
White inserts her kikashi in the lower left corner, ...

:
... before connecting at the top.

:
Black gives atari at White's two stones in the lower left.

:
White plays her final atari in the left centre.

: ( A 58ca)
White captures Black's two stones at the top.

White would benefit by one point in the Semeai Variation (compared to Black's best line of play below), if she connected her two stones in the lower left with , instead.

:
Black recaptures.

:
White connects her two stones in the lower left.

: ( 150 58cb)
Black captures White's single stone in the upper right, for easier comparison with the superordinate variation.

Black would be one point better in the Semeai Variation, if he defended in the left centre, instead.

: (146 58cc)
Black connects below.

He would lose decisively overall, if he connected above, with .

: (150 58cd)
Black destroys White's potential territory in the left centre.

Counter-intuitively, he must not defend his formation in the upper left centre, quite contrary to the situation some moves before.

:
White destroys Black's potential eyes in the centre.

:
Black must play a defensive move in the lower left corner first, when continuing with the Main Semeai.

Otherwise, White would be able to turn Black's lower left corner into a seki, as we have already seen in the subvariation above for Black's connection at .

Black plays 2/2 reductions.

Capture Variation:

Compared to the superordinate variation, ...

  • White destroyed one point of Black's territory in the left centre.
  • Black got an additional point of territory in the upper left corner.
  • Black got an additional point of territory in the lower left corner.
  • Black did not capture White's two stones in the lower left, so losing four points.
  • Black captures White's single stone in the right centre, so gaining two points.

In total, White gained one point.

White + 1 => White + 2

Semeai Variation:

Compared to the superordinate variation, ...

  • White destroyed one point of Black's territory in the left centre.
  • Black captured one White stone less in the upper left corner, so losing one point.
  • Black captured one White stone less in the lower left corner, so losing one point.
  • Black captured one White stone more in the lower left, so gaining two points.
  • White got an additional point of territory in the right centre.

In total, White gained two points.

Jigo => White + 2

Copyright © 2021 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

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