If white splits, I plan to tennuki and approach one of the sides:
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[go]$$Bcm1 19x19 board
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 7 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . 5 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
It's not incredibly urgent to respond, although "a" above is big.
I said I would say a bit more about the large enclosure. I'm certainly no expert, but it's something I've played in quite a few games, and I've looked at some pro games that use it. I guess the key tradeoff is size for safety: I'm mapping out a bigger space, at the cost of leaving weakness in the shape that can be exploited.
For example, if black extends with 1 below, white can follow with 2:
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[go]$$Bcm1 Example of aji
$$ ------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . X . 2 . 1 .
$$ | . . . , . . . . .
$$ | . . . . . . . . .
$$ | . . X . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]
This split is much safer than with the small enclosure, because white has more aji in the corner:
- Click Here To Show Diagram Code
[go]$$Bcm1 Example of aji
$$ ------------------
$$ | . . . . . . . . .
$$ | . . 6 4 5 . . . .
$$ | . . 2 X 7 O . X .
$$ | . . . 3 . . 1 . .
$$ | . 8 0 . . . . . .
$$ | . 9 X . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]
- Click Here To Show Diagram Code
[go]$$Bcm11 Example of aji
$$ ------------------
$$ | . . . . . . . . .
$$ | . . O O X . . . .
$$ | . . O X X O . X .
$$ | . . 2 X . . X . .
$$ | . O O 1 . . . . .
$$ | . X X 3 . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]
Of course, this isn't a bad result for black necessarily, but it gives some idea.