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[go]$$B Wedge!
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , . X X , . . |
$$ | . . X X O X . . . |
$$ | . X . X O . . X . |
$$ | . . X O O 1 O O . |
$$ | . O O . . . , . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

White can capture the wedging stone, but that's a losing mistake. Here's one of the variations:

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[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , . X X , . . |
$$ | . . X X O X . . . |
$$ | . X . X O 2 3 X 8 |
$$ | . 7 X O O 1 O O . |
$$ | . O O 5 6 a 4 . . |
$$ | . . . 9 0 . . . . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]

(If W4 at "a" instead, black gets the sente hane-connect on the first line.)

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[go]$$Bm11 B+2
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . 9 7 |
$$ | . . , . X X , 5 6 |
$$ | . . X X O X . b 8 |
$$ | . X . X O O X X O |
$$ | . X X O O X O O . |
$$ | 3 O O X O . O . . |
$$ | . 1 2 X O . . . . |
$$ | . . . 4 . . . . . |
$$ +-------------------+[/go]

If B15 were played at "b" instead, white would play out the local sente sequence and then win the ko in the lower left, getting a draw. For the same reason, black shouldn't atari before connecting with 19, leaving that ko threat is important. When black backs off with 15 and connects with 19, white has no opportunity to start and win the lower left ko, and the result will be B+2.

Better for white is to play atari from below after the initial wedge. There are multiple variations leading to a draw, here's one of them:

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[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , . X X , . . |
$$ | . . X X O X . 6 . |
$$ | . X . X O 3 . X . |
$$ | 9 5 X O O 1 O O . |
$$ | 7 O O . . 2 4 . . |
$$ | 8 . . . . . . . . |
$$ | . 0 . . . . . . . |
$$ +-------------------+[/go]

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[go]$$Bm11 Draw.
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . 9 7 |
$$ | . . , . X X , 3 4 |
$$ | . . X X O X 5 O 6 |
$$ | . X . X O X 1 X 2 |
$$ | X X X O O X O O 8 |
$$ | X O O . . O O . . |
$$ | O . . . . . . . . |
$$ | . O . . . . . . . |
$$ +-------------------+[/go]

If white connects on the other side with 4, this clamp is winning for black:

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[go]$$B
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . , . X X , . . |
$$ | . . X X O X . . . |
$$ | . X . X O 3 . X . |
$$ | . . X O O 1 O O . |
$$ | . O O . 4 2 , 5 . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]