:: Igo Hatsuyôron 120 (2021)

Variations of Our Solution (Ib)

KataGo's 2021 Solution

VAR

: ( 58eg)
White connects her pair of stones in the lower left corner, also giving atari at Black's stone above.

:
Black captures White's single stone in the right centre, which is his strongest resistance.

Alternatively, he could consider connecting at , instead, reverting to the superordinate variation. If he did, he would benefit by two points in the alternative Main Variation.

: (124 58ei)
White secures a second eye for her centre group, also occupying one of Black's liberties at the right.
Black can no longer set his hopes on entering the Central Semeai.

It would be a grave mistake to continue in the lower left corner immediately.
Please note that Black lost one tempo in the Main Semeai by his previous move, and is par with the Punishment Semeai Liberty Level again. This implies that he will be unable to connect at anyway (as long as White still follows the course of the Main Semeai).

:
Black defends his potential territory in the left centre.

:
Now, after her safety-first move at the top, White can capture at the bottom.

:
The Main Semeai continues.

:
White will be better in the Semeai Variation than in the Capture Variation, and so is able to play this hane at the upper edge before her decision point.

:
Black inserts his forcing move in the upper right, ...

:
... before continuing with the Main Semeai.

Black plays 0/1 reduction.

Please note that Black would lose another point in the Semeai Variation, if he played a territory-reducing move (for the Capture Variation) in the upper right.

Before the end of the game, Black will have to connect at .

Capture Variation:

Compared to the superordinate variation, ...

  • White destroyed one point of Black's territory in the upper left corner.
  • White's cumulated gain at the upper edge is two points.
  • Black's cumulated gain in the left centre is four points.
  • White captured Black's stone in the lower left, so gaining two points.
  • Black captured White's stone in the right centre, so gaining two points.
  • Black destroyed one point of White's territory in this area.

In total, White lost two points.

White + 3 => White + 1

Semeai Variation:

Compared to the superordinate variation, ...

  • White destroyed one point of Black's territory in the upper left corner.
  • White's cumulated gain at the upper edge is two points.
  • Black's cumulated gain in the left centre is four points.
  • White captured Black's stone in the lower left, so gaining two points.
  • Black captured one White stone less in the left centre, so losing two points.
  • White captured one Black stone more in the upper right centre, so gaining two points.

In total, White gained four points.

Black + 1 => White +3

Copyright © 2021 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

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