(Referenced by 648qg)

: ( 648qc)
Black ignores White's ko threat and connects the ko in the left centre.

:
White jumps to the upper one-two-point, aiming at establishing an eye in the corner.

:
Black occupies the other one-two-point, starting one exemplary sequence.

:
This move is favoured by KataGo.

However, Black would be two points better, if he played at , instead. Please refer to the other line of White's play in the upper left corner for details ( 648qg).

:
Black gives atari, in order to reduce the size of White's eye.

:
White has to capture Black's two stones for an eye.

:
Black must throw-in, in order to stop White from giving atari at .
Connecting at thereafter would be useless, as White has the follow-up atari at .

:
White captures Black's just played stone, turning Black's upper left corner into a seki.

:
Black continues in the right centre.

In the upper left corner, neither side can approach at .
If Black connects at , White will occupy his last outside liberty with .

Black plays 5/5 reductions.
But Black ends in gote, so White plays a reduction of ther own in the lower left corner.

Any other sequence, e.g. with at , and / or with at , would result in the same final score.

Due to the seki in the upper left corner, White will choose the Capture Variation.

Black will capture at before the end of the game.

Capture Variation:

Compared to the superordinate variation ...

• White's cumulated gain in the upper left corner is 19 points.
• Black destroyed two points of White's territory at the upper edge.
• Black got an additional point of territory in the left centre.
• Black captured one White stone there, so gaining one point.
• White got an additional point of territory in the right centre.
• Wihte did not capture Black's stone in the lower left, so losing two points.

In total, White gained 14 points.

White + 2 => White + 16