: ( 649aa)
White blocks at the upper edge, also giving atari at Black's just played stone.

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Black's push at the top is absolute sente.

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Black is able to connect at the upper edge.

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The Main Semeai continues.

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White stops Black from playing at , so creating profit outside the Main Semeai area, what would benefit him by two points in the Semeai Variation.

Black plays 1/1 reduction.

Capture Variation:

Compared to the superordinate variation ...

• White got an additional point of territory at the upper edge.
• Black destroyed one point of White's territory at the top.
• Black got one point of territory less in the left centre.
• Black destroyed one point of White's territory in the right centre.

In total, gains and losses compensate for each other.

White + 2 => White + 2

Semeai Variation:

Compared to the superordinate variation ...

• White got an additional point of territory at the upper edge.
• Black destroyed one point of White's territory at the top.
• Black got one point of territory less in the left centre.
• White captured an additional Black stone in the right centre, so gaining one point.

In total, Black lost two points.

Black + 6 => Black + 4