: ( 648aa)
Black continues with the Main Semeai.

We will assume that Black does not want to connect at in this subvariation before White's decision point.

: (A 648oz)
White continues with the Main Semeai.

Please note that White does not intend to capture at before her decision point, because this would be a mistake.

Black plays 1/1 reduction.

After her decision point, White will capture at and connect at thereafter.
Please note that she is able to do so in both Main Variations.

Capture Variation:

Compared to the superordinate variation ...

• White got one point at the upper edge.
• Black destroyed one point of White's territory in the upper right corner.

In total, gains and losses compensate for each other.

White + 2 => White + 2

Semeai Variation:

Compared to the superordinate variation ...

• White got one point at the upper edge.
• White captured an additional Black stone in the upper right corner, so gaining one point.

In total, Black lost two points.

Black + 4 => Black + 2