: ( 648mt)
Connecting the ko so early is a mistake.

:
Black's push reduces White's territory at the top by one point, as it did in the ko fight.

:
Black captures White's single stone at the top, so reducing White's territory by another two points. This gain is decisive and reveals White's mistake.

:
Black has to connect.

Black plays 2/2 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 lost one point of territory at the top.
• Black did not destroy one point of White's territory in the upper right corner.

In total, gains and losses compensate for each other.

White + 1 => White + 1

Semeai Variation:

Compared to the superordinate variation ...

• White lost one point of territory at the top.
• White captured one Black stone less in the upper right corner, so losing one point.

In total, White lost two points.

White + 1 => Black + 1