My last move was sente. At least, it was sente in a very general sense. I was threatening to take a large portion of the lower left with a move like E5 ( Maybe one D4 or F4 would work too )
- Click Here To Show Diagram Code
[go]$$Bc He can't let me do this.
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X O . X . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . X . X X O . . . . . . |
$$ | . . . X . . . . . . . O . O . X . . . |
$$ | . . . . B . . . . . X . . O X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
So I'm not surprised when my opponent invades. Indeed, it is almost forced.
I am, however, surprised that he invades in the manner that he did. After my last four moves, I've got some strength in the lower middle, and I expected him to play a bit lighter and more flexibly because of that.
I expected the high approach like this:
- Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X O . X . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . C . . . . . . . . . . . X . X . . |
$$ | . . . C . . . . X . X X O . . . . . . |
$$ | . . . X . W . . . , . O . O . X . . . |
$$ | . . . C . . . . C . X . . O X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
It leaves the options of the extension to J3, the second approach at C7, and attaching to the hoshi stone on top or on the bottom.
The move that he played is less flexible, and implies more of a commitment to one direction.
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So, what to do about it? At first glance, I see 4 possibilities:
1) Attack it from the left
2) Attack it from the right
3) Attack it from above
4) Ignore it and tenuki
Let's look at them one by one:
1) Attacking from the left seems proverbial ("Push your opponent toward your strength"),
but after a sequence of natural moves through 8, his group is as strong as mine, and has more eye space:
- Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . W . . . |
$$ | . . . . . . . . . . . . . . . W X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . W , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X O . X . . |
$$ | . . . . . . . . . . . . W O . . . . . |
$$ | . . . 3 . . . . . . . . . . X . X . . |
$$ | . . . . . . . 8 X 7 X X W . . . . . . |
$$ | . . . X . 2 . . 6 , . W . O . X . . . |
$$ | . . . . 1 O . . 4 5 X . . O X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
And it turns out that he is actually pushing ME against HIS strength ( the circled stones. ) When I look at this on a large scale, I don't like it at all.
2) Attacking from the left has nice shape for my lower middle group. Running doesn't look good for him:
- Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . a . . . X O . X . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . . 3 . . . . . . . . . . X . X . . |
$$ | . . . . . 2 . . X . X X O . . . . . . |
$$ | . . . X . . . . . , . O . O . X . . . |
$$ | . . 5 . . W . 1 . . X . . O X . . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
Even if he lives, I'm safe in the lower middle and making territory on the left. I can chase him with moves like 'a', and neutralize his right side influence while he runs along points that will eventually be dame.
Invading the corner is a second possibility:
- Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X O . X . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . 7 . X . X X O . . . . . . |
$$ | . . 3 X 5 . . . . , . O . O . X . . . |
$$ | . . 2 4 . W . 1 . . X . . O X . . . . |
$$ | . . . . . 6 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
...but I get a big wall, with central influence even stronger than his. At that point, I'm a bit ahead in territory, a bit ahead in influence, and my D16 stone is in the middle of the future contested territories.
I like this, but it simplifies way too much to be good for him. So he won't invade with 2 in the diagram above.
So when I attack from the left, he has to make the second approach:
- Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . X . X . X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . O , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X O . X . . |
$$ | . . . . . . . . . . . . O O . . . . . |
$$ | . . 2 . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . X . X X O . . . . . . |
$$ | . . . X . . . . . , . O . O . X . . . |
$$ | . . . . . W . 1 . . X . . O X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ----------------------------[/go]
I have to think about this option a bit. I'll continue this line of thought later.