: ( 222fn)
White starts the endgame in the lower left corner too early.

:
Black takes the opportunity to tenuki to the upper edge, giving atari at White's two stones there.

:
Black gains additionally by this move, despite he will end in gote.

:
White captures Black's stone at the lower edge.

...

Black must not play any reduction.

Capture Variation:

Compared to the superordinate variation ...

• Black's total gain at the top is three points.
• White captured Black's stone in the lower left, so gaining two points.

White lost one point.

White + 2 => White + 1

Semeai Variation:

Compared to the superordinate variation ...

• Black's total gain at the top is three points.
• White captured Black's stone in the lower left, so gaining two points.

White lost one point.

Black + 3 => Black + 4