:
Black starts with cutting White's upper partial group apart, which suffers from a lack of liberties.

:
White might try to cut on the third line, instead, but will not get a better result than here.

:
Black might try to give atari with a move at 4, instead, but will not get a better result than here.

@

:
Black has got seven ko-threats.

/// :
White tries to connect on the third line.

:
Black would get no better result, should he connect at , instead.

:
Black has got six ko-threats.

/// :
Black gives atari from the other side.

:
It would be a mistake to capture with , instead. Thereafter, Black had the atari of 4 as additional ko-threat.

:
Black has got seven ko-threats.