: ( 648mt)
White connects her single stone at the upper edge.

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Black continues with the ko fight in the centre.

He could simplify the issue, if he continued with the Main Semeai, instead.

Ko: ; ; ; ; ;

...

Ko: ; ; ; ;

; :
Please understand these two moves as replacement for White's kikashi , in the centre, which had been played too early by us.

We now know that Black's atari in the upper left centre cannot be counted as an additional ko threat.

; ; ; :
These ko threats cost one tempo in the Main Semeai each. Eventually, Black is two over par.

Please note that we did not update the board's border colour during this ko sequence.

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Black does not have any valid ko threat left that would not lose points unnecessarily.

Joachim found that Black's throw-in at in the upper right is a valid ko threat.

White is barely ahead in ko threats (2 x vs. ), so our earlier mistake does not affect the outcome of the game. White would still win the ko fight, even with one effective ko threat less.

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White has to connect the ko.

Otherwise, Black will capture, and connect, gaining decisively.

Black plays 1/2 reductions.

Later, White will play her kikashi , in the lower left corner, so that Black must capture at before the end of the game.

Capture Variation:

Compared to the superordinate variation ...

• White's cumulated gain at the upper edge is two points.
• White got one point of territory less at the top.
• Black destroyed three points or White's territory at the top.
• White destroyed one point of Black's territory in the upper left corner.
• White captured Black's stone in the lower right, so gaining two points.

In total, White gained one point.

White + 1 => White + 2

Semeai Variation:

Compared to the superordinate variation ...

• White's cumulated gain at the upper edge is two points.
• White got one point of territory less at the top.
• White captured an additional three Black stones at the top, so gaining three points.
• Black captured an additional White stone in the upper left, so gaining one point.
• White captured one Black stone less in the lower right, so losing two points.

In total, White gained one point.

White + 1 => White + 2