Life In 19x19

Loons wrote:Is black not strong locally ?

I think B is quite strong locally.

That reply is by far the most aggressive.
Most people either choose this:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . X . . |
$$ | . . B W . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |[/go]

...in which black concedes running room to white while taking sure but modest territory. The reducing stones are always a concern for white, and he usually spends a move to connect them to something midway through the game.

The solidly aggressive extension is sometimes played:

Click Here To Show Diagram Code

[go]$$Wcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . b b . . . . . . . . . . . . . . . . |
$$ | . . b X B . . . . . . . . . . . X . . |
$$ | . . . W . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |[/go]

...in which black concedes both some eastward running room to white, and some westward invasion, in return for a solid position. Black always takes 'a' and usually something around 'b'.

But the upper hane is notable in that it blocks both an immediate run eastward, and any play underneath. The former is obvious. The latter looks like this:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . 6 . . . . . . . . . . . . . . . |
$$ | . . 1 X . . . . . . . . . . . . X . . |
$$ | . . 2 W X . . . . . . . . . . . . . . |
$$ | . . 4 3 . . . . . . . . . . . . . . . |
$$ | . . . 5 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

...in which black has solid territory and white has zilch.

So at this point, I'm outside my comfort zone and relying on a very fuzzy memory. White has several options:
1) The outside wall
2) The ko
3) tenuki

The outside wall looks like this: ( as noted before, it is good to have the favorable ladder - shown here with the blue arrow. )

Click Here To Show Diagram Code

[go]$$Wcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X 7 . . . . , . . . . . X . . . |
$$ | . . . 4 3 . . . . . . . . . . . . . . |
$$ | . . . X 1 2 . . . . . . . . . . X . . |
$$ | . . . W X 5 . . . . . . . . . . . . . |
$$ | . . . . 6 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ { AR G13 K10 }[/go]

Or the outside wall looks like this:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . a . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . 2 7 . . . . . . . . . . . . . |
$$ | . . . X 1 3 . . . . . . . . . . X . . |
$$ | . . . W X 5 . . . . . . . . . . . . . |
$$ | . . . 4 6 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |[/go]

The important thing for me is to be able to suppress the moyo and not have to come back an d protect 'a' in certain gote. To that extent, both of the previous diagrams work for me. Whether I end in gote or not is not clear, as getting to the corner is big.

The ko looks like this:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . 5 X 1 . . . . . . . . . . . X . . |
$$ | . . 4 W X . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |[/go]

It is not at all clear who does better in a ko.

My current preferrence is for the wall. I have to think about it a bit more.

Click Here To Show Diagram Code

[go]$$Wcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X 8 . . . . . . . . . . . X . . |
$$ | . . . W . . . . . . . . . . . . . . . |
$$ | . . . . . a . . . . . . . . . . . . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I feel like he would have done some of that light dodgy business if I gave him more space to. He might, still, but it seems harder on the board this way. This is kind of hard to respond to (the best I seem to have is 'a', because against many moves, black can just sacrifice one stone and jump out with the other for a successful reduction.

If you atari my last move, I extend.

Click Here To Show Diagram Code

[go]$$Bcm20
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . 1 . . . . . . . . . . . . . . |
$$ | . . 5 X O 2 . . . . . . . . . . X . . |
$$ | . . 4 O X . . . . . . . . . . . . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Click Here To Show Diagram Code

[go]$$Bcm20
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . 1 . . . . . . . . . . . . . . |
$$ | . . 5 X O 2 . . . . . . . . . . X . . |
$$ | . . 4 O X 7 . . . . . . . . . . . . . |
$$ | . . 8 3 6 . . . . . . . . . . . . . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The only question in my mind, really, was whether 24 should be above or below the two stones. If this is safe, this seems best, as it doesn't grant the atari and the aji that comes with. As I can't seem to read anything too bad, I'm going with this. White could play more aggressively to break into my left side, by forcing me to capture 23, but his resulting stones will all be weak and potentially heavy. I feel like I can be content with this unless I'm missing something huge.

Since B is strong locally, the atari is OK, but the other way (B atari at instead) is still better:
see also and here: www.lifein19x19.com/forum/viewtopic.php ... 3&start=80

Because W can do better than Chew's variation --
W can close B and now the aji in this corner is not good for B:

Click Here To Show Diagram Code

[go]$$B
$$ -----------------------
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . O . . . O .
$$ | . . . X . . . . . , .
$$ | . . . . 1 8 . . . . .
$$ | . . 5 X O 2 . . . . .
$$ | . . 4 O X . . . . . .
$$ | . . 6 3 . . . . . . .
$$ | . . . 7 . . . . . . .
$$ | . . X , . . . . . , .
$$ | . . . . . . . . . . .[/go]

Compare:

Click Here To Show Diagram Code

[go]$$B
$$ ---------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . O .
$$ | . . . X . . .
$$ | . . . 3 2 . .
$$ | . . . X O 1 .
$$ | . . . O X . .
$$ | . . . . . . .[/go]

No, I have no pretentions of living down there. But the aji is well worth it.

More later...

To put things in perspective: remember that a few moves back I was faced with a burgeoning black left side, and a my own thinness up top. To remedy both of those problems simultaneously, I threatened to invade the left, assuming that I could either get an invasion or an outside wall. MHO made the most aggressive possible reply, denying any chance of an invasion, so I'm going for the wall. Its approximate future location is indicated by the triangles.
Not only does a wall hold him back on the left, but I don't have to make small gote moves up top, for once the wall is in place, the two circled stones are no longer thin, but function as extensions off of the wall.

Click Here To Show Diagram Code

[go]$$Bcm20
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . W . . . W . . . . . |
$$ | . . . X . T . . . , . . . . . X . . . |
$$ | . . . . X T . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X T . . . . . . . . . . . . . |
$$ | . . O X . T . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

So the issue for me is how to construct that wall.

Note to beginners:

The immediate threat, of course is the double atari at 'a', and the escape at 'b'. Not surprisingly, those are his two best options.

Note to beginners:

Click Here To Show Diagram Code

[go]$$Bcm20
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . W . . . W . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . O X a . . . . . . . . . . . . . . |
$$ | . . . b . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Let's look at one possible black response:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . W . . . W . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X 4 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X 2 . . . . . . . . . . . . . |
$$ | . . O X 3 . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White 4 starts to assemble the pieces of wall, and is more aggresive than it looks.
Because of the aji of the three sacrifice stones, taking the corner is big:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 0 . . . . . . . . . . . . . . . . |
$$ | . . 9 8 . O . . . W . . . W . . . . . |
$$ | . . . X 6 . . . . , . . . . . X . . . |
$$ | . . . 7 X 4 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X 2 . . . . . . . . . . . . . |
$$ | . . O X 3 5 . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

( BTW, note how bulky and clumpy the black stones are becoming )

One possible continuation is like this:

Click Here To Show Diagram Code

[go]$$Bc 9 @ 4
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 2 O . . . . . . . . . . . . . . . . |
$$ | . 1 X O . O . . . W . . . W . . . . . |
$$ | . 5 4 X O . . . . , . . . . . X . . . |
$$ | . 8 7 X X O . . . . . . . . . . . . . |
$$ | . 6 X X O O . . . . . . . . . . X . . |
$$ | . 3 O O X O . . . . . . . . . . . . . |
$$ | . 0 O X X X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Another is like this:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 3 O 1 . . . . . . . . . . . . . . . |
$$ | . 5 X O 2 O . . . W . . . W . . . . . |
$$ | . . 4 X O . . . . , . . . . . X . . . |
$$ | . . . X X O . . . . . . . . . . . . . |
$$ | . 6 X X O O . . . . . . . . . . X . . |
$$ | . . O O X O . . . . . . . . . . . . . |
$$ | . . O X X X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Note to beginners:

My current guess at black's best(?) result is this:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 2 O . . . . . . . . . . . . . . . . |
$$ | 4 1 X O . O . . . W . . . W . . . . . |
$$ | . 5 . X O . . . . , . . . . . X . . . |
$$ | . . . X X O . . . . . . . . . . . . . |
$$ | . 3 X X O O . . . . . . . . . . X . . |
$$ | . . O O X O . . . . . . . . . . . . . |
$$ | . . O X X X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

It is all sente for white. And black will still have to fill one more point of his territory in gote sometime in yose.

----

That was one black response. Let's look at the other:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . W . . . W . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . O X 1 4 . . . . . . . . . . . . . |
$$ | . . 3 2 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White 2 threatns to run, so 3 is forced. White 4 is sente.

Note to beginners:

Wite 6 threatens the previously shown mischief in the corner; 7 defends; 8 reinstates the threat.

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 7 O . . . W . . . W . . . . . |
$$ | . . . X . 8 . . . , . . . . . X . . . |
$$ | . . . . X 6 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . O X 1 4 . . . . . . . . . . . . . |
$$ | . . 3 2 5 . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 7 O . . . W . . . W . . . . . |
$$ | . . . X 9 8 . . . , . . . . . X . . . |
$$ | . . . . X 6 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . O X 1 4 . . . . . . . . . . . . . |
$$ | . . 3 2 5 0 . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Note to beginners:

How consistent is the 2.5-3 pts per stone rule? I had heard that, but I assumed it applied to walls on the 3rd or 4th line. A wall on the 6th line must be worth less, right?

I'm also curious as to how you would work things like extensions into that. Presumably a wall that already has a good extension, or that completes a moyo, is worth more, but do you have any sense of how much more?

Unfortunately, both players do not realize the problem started with the atari.
In fact, much of the analysis in Post #88 shows the issues stemming from it.
IMO, the evaluation of the situation should start with this sequence instead
(and it'd be nice for beginners to be aware of the differences between the two ataris) --

Click Here To Show Diagram Code

[go]$$B
$$ ---------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . O .
$$ | . . . X . . .
$$ | . . . 3 2 . .
$$ | . . . X O 1 .
$$ | . . . O X . .
$$ | . . . . . . .[/go]

Not a whole lot less. The effect of a wall falls off as some function of the inverse of the distance. ( I suspect that the function is one term and something between x^1 and X^2 ) In this case it is like having a wall on the fourth rank and having someone chop off rows 's' and 't'.
Or maybe a better way to consider it is a fourth-rank wall with a few stones on the opposite side of the board, which would locally neutralize the effect of the wall 11 or 12 stones away.

How much is the difference in value ( to the east ) of this wall:

Click Here To Show Diagram Code

[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

...and this wall:

Click Here To Show Diagram Code

[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . O . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . O . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Presumably, whatever effect the wall might have on the two most eastern rows is zero, as it is neutralized by the white stones there. But, in practice, would you consider the wall worth sustantially less?

What then, is the difference between the wall above and the one below?

Click Here To Show Diagram Code

[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . , . . . . . , . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Well, since it takes 2 moves to play those stones, and the current temperature is maybe 10 *shrug*, then it might follow that the stones - if perfectly placed - would raise the value of the wall about 20 points. But they are not perfectly placed. The one at J17 is too close to the wall and too far away from its neighbor. It should be at L16 or L17, I think. That imperfection is hard to evaluate.

I'm not sure I totally agree with Joaz's last choice.

If he wants a diagram like this (taken from his explanation, with marks added):

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X 4 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X 2 . . . . . . . . . . . . . |
$$ | . . W X 3 . . . . . . . . . . . . . . |
$$ | . . . B . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I do not see why he needs the marked stone exchange. The exchange seems to add to the number of stones sacrificed, while allowing black to fix that local area. I'm not sure what good it does for white. If he wants to go that route, I'd think it'd be better to skip the exchange, and just play what he wanted to:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X 3 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X 1 . . . . . . . . . . . . . |
$$ | . . C X 2 . . . . . . . . . . . . . . |
$$ | . . C C . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Yes, the marked area, above, will probably not be totally useful for white right now, but why make the exchange to allow black to close off that area?

I'm not entirely convinced by his reasoning either, although I think the result is close to the same. However, I think this is a really poor overall final result on the left for White:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 6 O . . . O . . . O . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . X 5 . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X 3 . . . . . . . . . . . . . |
$$ | . . 1 X 4 . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Sure, it requires , but is so huge that I can't see it being omitted, and it's fairly obviously urgent after . It's a really really huge corner and side.

I think the order matters: if first, then later if W turns at (a),
B will not make the empty triangle at (b); B will be able to block at (c):

Click Here To Show Diagram Code

[go]$$W
$$ ---------------
$$ | . . . . . . .
$$ | . . . . . . .
$$ | . . . . . O .
$$ | . . . X . . .
$$ | . . . . X . .
$$ | . . X X O O .
$$ | . . O O X 1 .
$$ | . . a X 2 . .
$$ | . . c b . . .
$$ | . . X , . . .
$$ | . . . . . . .[/go]

So if W wants the (a)-(b) exchange, W needs to do it first.
But maybe W wants to save the exchange until later?

This doesn't seem too bad. I'm capturing some stomnes and making fourth-line territory. It seems likely that Joaz is going to use forcing moves against my stones here to take a bit of thickness here, but I think that's doable. E14 looks unlikely to link solidly in sente, so his thickness will either be flawed or gote, in which case I can start reducing. If I reduce, I'll have to consider either capping one of the low middle under-the-star-point stones on the top and bottom, or just leaning on his framework from the right side.

Click Here To Show Diagram Code

[go]$$Wcm21
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 7 8 . O . . . O . . . O . . . . . |
$$ | . . 9 X . . . . . , . . . . . X . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . . X . . |
$$ | . . O O X . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . . 6 . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . O . . . . . . . . . . X . . |
$$ | . . . X . . . . . , . . . . O , . . . |
$$ | . . . . . O . . . O . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I am also a little concerned that he could steal my corner here. While he could do so in gote with a fairly safe joseki, he could also do something aggressive like this. My concern here is the number of liberties I have on the D14 group. This is enough of a concern that I may play to protect the corner soon, if he doesn't get there first. Or at least threaten F17, so he cannot take the corner without sacrificing that area.