I think White should have played from the other side--and not right away but after attacking the group in the center-left, first (

doesn't threaten to kill the group on the right, so is not sente). As I mentioned before, White's winning plan is to build territory in the middle. I haven't read here very thoroughly so I'm not sure how best to attack but maybe with "a" or "b."
$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . b . . . . . O X . . |
$$ | . . . . . . . . a . . . . O O X X . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . 1 . X X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . b . . . . . O X . . |
$$ | . . . . . . . . a . . . . O O X X . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . 1 . X X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Now, Black should destroy some of White's potential in the center by jumping to

. This move also applies pressure on the White group above it, for it is not yet completely alive, either.
$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . O O X X . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . 2 . X X X . . |
$$ | . . . . . . . . . . . . . . . . . 1 . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . O O X X . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . 2 . X X X . . |
$$ | . . . . . . . . . . . . . . . . . 1 . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
However, Black needs to be careful not to die in case White robs him of eyespace on the edge with something like

. Then, Black may fall into a splitting attack, but both Black groups should survive, in my estimation. The middle has plenty of space, plus the nearby White groups have weaknesses, too. Next, Black could consider playing

, for example.
$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . 4 O O X X . 3 |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . X . X X X . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------
- Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . O . . O O . . . . . . . . . . . . . |
$$ | . O . O . O X . . . . O . X . O O X . |
$$ | . O O . O O . . X . X . O . X . X . . |
$$ | . X O O . X X X O X . . . O X X . . . |
$$ | . X O O O O O O O . X . X X . . . . . |
$$ | . X O X X O . X O O X . . O X . X . . |
$$ | . X X X O . O X . X O . . O X O . . . |
$$ | . O . X . . . . . X . . . O X . . . . |
$$ | . . O X X X X . . . . . . O . . O . . |
$$ | . . . O X O X . X , . . . . O . O . . |
$$ | . . O . O O . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . 4 O O X X . 3 |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . X . . . . . . . . . X . X X X . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . , . . . O . , O . . |
$$ | . . X X . . O . . O . . . . . O . . . |
$$ | . O X O O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]