:: Igo Hatsuyôron 120 (2020)

Variations of Our Solution (IIIa)

No Early Kikashi

VAR (.1) (.2) (.3)

: ( 648fi)
White follows Dany's suggestion of leaving the Nakade Sequence temporarily unfinished.

:
Black throws-in at the left edge, occupying the point that White just disdained.

:
White has to play her kikashi in the hanezeki.

:
White continues with the Main Semeai.

There is no need to capture immediately with .

:
White prioritises the Semeai Variation, so she chooses Dany's Sacrifice.

:
White lets happily capture hr stones in the lower left corner.

:
White has to recapture.

...

:
White's continuation with the Main Semeai simplifies the issue.

She will not benefit from fighting the ko at the left edge, instead.

:
White has to play this atari sooner or later.

:
Please note that the marked regions in the left centre, and at the upper edge, are still unsettled.
Usually, when analysing this position, there will be no assistance from coloured board edges; therefore, we will use another method here.

We will continue with the mutual occupation of opponent's liberties in the Main Semeai under the assumption that none of the surrounding groups (i.e. Black's in the left centre) can be captured, even if being in atari.
Absolute priority takes the determination of the number of Main Semeai Liberties.

:
Black has played his oki into White's four-point eye at the left. We have reached the point, when White has to decide between the Capture, and the Semeai, Variation.

One Black move is still missing in the left centre; there are two options for executing them, which we will explain in detail later.
On the right, Black has ten liberties, nine direct liberties (), and one approach-move liberty ().
In total, we can count nine Main Semeai Liberties for Black.

This implies that White is unable either to connect Dany's Ko with , or to connect her single stone at the upper edge. Both moves would cost her a tempo in the Main Semeai, resulting in Black's survival in the Semeai Variation.

Now let's return to Black's options at the left.

  • If Black captured the ko with . White would still be unable to connect at , so Black could connect with afterwards. Then, White would be able to connect at .
  • Otherwise, if Black connected at , White would still have to continue at the right. Thereafter, Black could capture at at the upper edge, White would block at . Each side would connect one of these ko.
Both options are equivalent.

:
White's only option left is to follow the Main Semeai.

:
We follow Black's first option here.

; :
Both sides connect.

Capture Variation:

Compared to the superordinate variation ...

  • White's cumulated gain at the upper edge is two points.
  • Black gained an additional point of territory in the lower left corner.
  • Black captured one White stone in the left centre, so gaining one point.
  • Black got one point of territory there.
  • White did not capture Black's five-stone nakade, so losing five points.
  • Black did not destroy one point of White's territory in the upper right corner.
  • Black's cumulated gain at the lower left edge is five points.
  • Black captured two White stones in the lower left, so gaining four points.

In total, White lost 14 points.

White + 1 => Black + 13

Semeai Variation:

Compared to the superordinate variation ...

  • White's cumulated gain at the upper edge is two points.
  • Black gained an additional point of territory in the lower left corner.
  • Black captured one White stone in the left centre, so gaining one point.
  • Black got one point of territory there.
  • White did not capture Black's five-stone nakade, so losing five points.
  • White captured one Black stone less in the upper right corner, so losing one point.
  • Black captured one White stone less in the lower left, so losing two points.
  • White's cumulated gain at the lower left edge is five points.

In total, gains and losses compensate for each other.

White + 1 => White + 1

Copyright © 2020 Thomas Redecker.

Design by Jan van Rongen, modified by Thomas Redecker.

L e g a l   n o t i c e