I'd play J4, which according to my reading, threatens the follow up at N9, after which the black group has only one solid eye at N7, and possible eye at the bottom that depends on black winning a ko.
This is not a pleasant ko for black, for white has an internal ko threat at O8, and large external threats at D9 then E11, and Q15.
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | O X . . . . X . . . . . . X . . . . . |
$$ | . O X X X X . O . X O X O X . . . . . |
$$ | . O O O X O O . O O . O O X . X . . . |
$$ | . X O . O O . . . X O . X O . C X . . |
$$ | X . X O X O . . . . . . X O . O O X . |
$$ | . X O O . . . . . . . . X O X X . . . |
$$ | . . . . . . . . . . . O X X O X X X . |
$$ | . X . O C . X . . O . O X . O . O . . |
$$ | . . X , . X . . O , X O O . O O X . . |
$$ | . X O C X . . . . . X X 3 X O X O O . |
$$ | . X X O . . . . . O X . X C O . O X . |
$$ | . X O . . . . . . O O X S X O O X . X |
$$ | . . . . . . . . . O X X X . O X X X . |
$$ | X X X . . . . . . O X O O O O . . . . |
$$ | X O O O . O O . 1 , X X O . O , X . . |
$$ | O O . . . O X X . X X . X O X X . X . |
$$ | . . . . . O O X . . . X O O O X O . . |
$$ | . . . . . . . . . . . O . O . O . O . |
$$ ---------------------------------------[/go]
If black plays safe by taking N9 for himself and securing two eyes, white takes his profit in sente with F8 threatening E10.
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | O X . . . . X . . . . . . X . . . . . |
$$ | . O X X X X . O . X O X O X . . . . . |
$$ | . O O O X O O . O O . O O X . X . . . |
$$ | . X O . O O . . . X O . X O . . X . . |
$$ | X . X O X O . . . . . . X O . O O X . |
$$ | . X O O . . . . . . . . X O X X . . . |
$$ | . . . . . . . . . . . O X X O X X X . |
$$ | . X . O . . X . . O . O X . O . O . . |
$$ | . . X , 5 X . . O , X O O . O O X . . |
$$ | . X O . X . . . . . X X 2 X O X O O . |
$$ | . X X O . 3 . . . O X . X . O . O X . |
$$ | . X O . . . . . . O O X . X O O X . X |
$$ | . . . . . . . . . O X X X . O X X X . |
$$ | X X X . . . . . . O X O O O O . . . . |
$$ | X O O O . O O . 1 , X X O . O , X . . |
$$ | O O . . . O X X . X X . X O X X . X . |
$$ | . . . . . O O X . . . X O O O X O . . |
$$ | . . . . . . . . . . . O . O . O . O . |
$$ ---------------------------------------[/go]
Assuming that black defends against that, white continues grabbing territory like this:
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | O X . . . . X . . . . . . X . . . . . |
$$ | . O X X X X . O . X O X O X . . . . . |
$$ | . O O O X O O . O O . O O X . X . . . |
$$ | . X O . O O . . . X O . X O . . X . . |
$$ | X . X O X O . . . . . . X O . O O X . |
$$ | . X O O . . . . . . . . X O X X . . . |
$$ | . . . . . . . 5 . . . O X X O X X X . |
$$ | . X . O . . X . . O . O X . O . O . . |
$$ | . . X , . X . . O , X O O . O O X . . |
$$ | . X O 4 X . . . . . X X 2 X O X O O . |
$$ | . X X O . 3 . . . O X . X . O . O X . |
$$ | . X O . . . . . . O O X . X O O X . X |
$$ | . . . . . . . . . O X X X . O X X X . |
$$ | X X X . . . . . . O X O O O O . . . . |
$$ | X O O O . O O . 1 , X X O . O , X . . |
$$ | O O . . . O X X . X X . X O X X . X . |
$$ | . . . . . O O X . . . X O O O X O . . |
$$ | . . . . . . . . . . . O . O . O . O . |
$$ ---------------------------------------[/go]