(Referenced by 822)

: ( 731)

But by starting the ko on the left side, White may unnecessarily open a Pandora's box, because this ko-fight may become very complicated. We will explain just some of our thoughts, because this could be a surprising second chance for Black to win the game, after having missed the guzumi earlier. However, the opportunity for winning the game by playing the guzumi has closed with the completion of the Crosscut Sequence (please refer to the section "The Timing of the Guzumi"; 813).

:
If Black lives in the upper right with , White must win the ko, because she can no longer afford to capture Black's centre group (). Now, the outcome depends on the upper left corner, i.e. on the point for White, and the point for Black.

: (104 735)
White plays the tsuke of Yamada Shinji. She cannot finish the ko-fight now, with a move at .

: (A 736)
Black could re-capture the ko, instead, because he will not win by following the usual endgame sequence.

:
If White is able to win the ko (with here) after reducing Black's top left corner (starting with here), she will get a sure win, by a few points, according to our calculation.

:
We show an amateurish idea of the following endgame.

White wins by four points.

It is a very astonishing aspect of this problem that living with the group in the upper right without having the seki in the lover right quadrant of the board resolved does not profit Black.

Let us first return to the result of the Capture Variation of our solution, where Black also played the guzumi, and compare it to the flow of this sub-variation.

By further capturing in the nakade on the left side White gains an additional 3 + 4 = 7 prisoners ( / / ).

In the centre, White captures 20 Black stones ( / / ), to get 38 points of territory.

On the right side, Black gets 64 points by capturing 32 White stones ().

In the lower right corner, each side captured a further four stones, which cancels each other out.

So Black gets a surplus of 64 - 38 - 7 = 19 points.

Seen the other way round, this means that Black is behind by 19 points in this sub-variation at the moment, he decided to try to live in the upper right.

You will recognize that the gains and losses of the endgame on the left side of the board (compared to our solution) compensate for each other. In the other parts of the board, seen from Black's point of view, there is a gain of five points in the centre (3 * 1, 2), and a gain of a further five points in the upper right (3 * 1, 2), because White did not have her sente sequence available here, to close the borders like in the path of our solution.

However - Black wins the Capture Variation of our solution by five points - a gain of only ten points is not sufficient to make up for the initial 19-points-disadvantage. As demonstrated above, White wins by four points.