: ( 648qa)
Black connects in the upper right, securing some territory there.

:
White pushes from above.

:
Black captures White's stone below immediately.

He might consider recapturing the ko in the left centre with , but this would lengthen the sequence only. Black would have to come back to soon.
White has five valid ko threats here (4 x lW, - played too early by us), while Black has only four (), so White would win the ko fight.
Additionally, Black would lose one point in the Semeai Variation, once he had used his last-but-one ko threat, as can be seen in the superordinate variation.

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White connects the ko.

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The Main Semeai continues.

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White plays her remaining kikashi in the lower left corner.

Black plays 3/4 reductions.

If he played 4/4 reductions, the score of the Main Variationas would be interchanged.

Before the end of the game, Black will have to capture at in the lower left corner.

Capture Variation:

Compared to the superordinate variation, ...

• White got an additional three point of territory at the top.
• Black got an additional point of territory in the right centre.
• White did not capture Black's stone in the lower left, so losing two points.

In total, gains and losses compensate for each other.

White + 2 => White + 2

Semeai Variation:

Compared to the superordinate variation, ...

• White captured three Black stones less at the top, so losing four points.
• White captured an additional Black stone in the right centre, but lost one point of territory there and in the upper right corner, so the net effect is a gain of one point for White.
• White capture one Black stone more in the lower right, so gaining two points.

In total, Black gained one point.

White + 2 => White + 1