I think this is a better way of analysing this potion with tewari. If we start with the following position, and say black wants to stop white
a damaging the corner (tenuki is not the end of the world if there's something really important elsewhere, like a fight this was leaning for).
- Click Here To Show Diagram Code
[go]$$c
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . X X . O . .
$$ | . X a X O . . . . ,
$$ | . . . O . . . . . .
$$ | . . O . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]
If black just connects at 1 then white has sente. What would white do? Tenuki? Maybe
a if local? White wouldn't play 2 to close off the left side with it so open, it's an endgame move, and a thin one at that. So exchange of 1 for 2 is significantly good for black (compare to what white can do if black tenukid before 1).
- Click Here To Show Diagram Code
[go]$$c
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . X X . O . .
$$ | . X 1 X O . . . . ,
$$ | . 2 . O . . a . . .
$$ | . . O . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]
Then black plays 3 and white connects at 4. This exchange helps white, who got stronger on the outside, though black can capture the edge stone for endgame. Although white is a stronger shape, it's also rather heavy and needs an extension (but it's black's move). I think this exchange is less bad for black that the last one was bad for white, so overall black has gained a bit. As black has sente he can play such as
a/b to separate the top stone, pincer the left, or elsewhere.
- Click Here To Show Diagram Code
[go]$$c
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . X X . O . .
$$ | . X X X O b . . . ,
$$ | . O 3 O . . a . . .
$$ | . . O 4 . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]
So, locally speaking, if black is sure white will play this way (big if) I think the wedge is generally better because black made one bad exchange, white made a worse one, and black got sente instead of gote.
What about that if? White has other choices: one would be to play atari of before and tenuki, or this atari and cover at 4. Can black hane at
a to cut and fight? That depends on a ladder as after
b he has to defend at
c.
- Click Here To Show Diagram Code
[go]$$c
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . c . . . . . .
$$ | . . . 2 X X b O . .
$$ | . X 3 X O 4 a . . ,
$$ | . . 1 O . . . . . .
$$ | . . O . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]
Maybe black would do this. This might make sense for white if the top side is interesting and the left not.
- Click Here To Show Diagram Code
[go]$$c
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . 7 . . . . . .
$$ | . . . O X X . O . .
$$ | . X X X O O 6 . . ,
$$ | . . X O . . . . . .
$$ | . . O 5 . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]
Conclusion? Meh, go is hard.