: ( 222ia)
Black closes his upper left corner, but this move comes too early, and so is a grave mistake.

Please note that this move does not affect the semeai conditions at the right.

:
White destroys two points of Black's territory in the upper left corner, in sente.

:
It is safe for White to block at the top, taking profit at the top.
At any time she wants, , will turn the upper left corner into a seki.

:
Black takes profit at the lower edge in return.

:
Black occupies White's approach-move liberty in the corner.

:
White continues with the endgame in the left centre.

Black's previous move does not carry a real threat.
Black needed another two moves (, ) to capture White's stones, before he would be able to occupy White's liberty at . However, he would fall prey to the Pusishment Semeai thereafter.

Black must not play any reduction.

After her decision point, White will descend to at the upper edge. Black must reply at .

Capture Variation:

Compared to the superordinate variation ...

• White destroyed two points of Black's territory in the upper left corner.
• White's cumulated gain at the top is five points.
• Black got an additional three points of territory in the lower left corner.

In total, Black lost four points.

Black + 2 => White + 2