99. topazg vs sevis

topazg · Post by **topazg** » Wed Feb 23, 2011 5:39 am

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Spoiler:

Furthermore, some of Black's options regarding separating White's stones are becoming less enticing now:

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . 4 . . . . . . . . . . X . . | $$ | . . . . . c . . . . . . . . . . . . . | $$ | . . . b 3 5 . . . . . . . . . . . . . | $$ | . . . X b O 6 . . , . . . . . X . . . | $$ | . . . . a . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

"a" has become awkward to play to help settle the group as :w25:

helps greatly in the push and cut on the "b" points. I wasn't overly concerned about the push and cut (although it's undeniably big compared to White getting to play at "c"), but having just increased its value with the sequence in the top left, this makes it harder for Black to get a good result from it.

Some interesting asides:

Click Here To Show Diagram Code: [go]$$Bcm24 Diagram A $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . X . . | $$ | . . . . . 2 . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$Bcm24 Diagram B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . . . 2 . . . . . . . . . . . . . | $$ | . . . X . a . . . , . . . . . X . . . | $$ | . . . . . O . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The value of :w25:

in diagram A is a fair bit lower than as in diagram B because unlike B (where Black can cut forcefully with "a"), it is hard for A to find a strong followup to the attempt to cut. Particularly as Black has prioritised the upper left quadrant with regards to points, it is hard to get sufficient profit from the following to compensate for pushing White behind on the 4th line:

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . a a a a . . . . . . . O X . . | $$ | . . . . a a a a . . . . . . . . X . . | $$ | . . . . a a a a . . . . . . . . . . . | $$ | . . . X . 6 . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . 2 . . . . . . . . . . X . . | $$ | . . . . . . 5 . . . . . . . . . . . . | $$ | . . . . 1 3 . . . . . . . . . . . . . | $$ | . . . X . O 4 . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Whilst splitting groups is important, splitting attacks need to either lead to killing something, or developing territory whilst attacking (or thickness so that the process can be repeated elsewhere, but eventually you either kill something, get territory, or the attack is a failure). Here Black needs to be careful to not just end up with stones on dame in exchange for _losing_ points at "a".

That said, getting thickness in the top left has increased the concern of the cut, as the weakness of D10 is much lower here than in some of the other variations I put in earlier moves. Big moves for me at the moment:

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . a . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O b . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . b . . . | $$ | . . 2 O . . . . . . . . . . . . X . . | $$ | . . . . . a . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

EdLee · Post by **EdLee** » Wed Feb 23, 2011 6:39 am

Spoiler. EDIT: Unhidden after :w27:

.

Sevis wrote:Time to go on the offensive, I think. Thoughts may come later, so far, this is simply the move that feels most right.

Unfortunately, :b24:

is the wrong idea, wrong direction, wrong tactic (wrong shape),
and it does exactly the opposite of B's intention (as topazg pointed out in his notes for :w25:

).
It pushes from B's thickness :bs:

, touches and strengthens :wt:

, and hurts :bc:

:

Click Here To Show Diagram Code: [go]$$Bm24 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . # O # # . . # . , . . . O . X . . . | $$ | . . # . . # . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 Q . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . B . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Compare--

helps

, splits W's 2 weak stones :wt:

and

, does not touch or strengthen :wt:

, and pushes :wt:

toward B's thickness :bs:

:

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . # O # # . . # . , . . . O . X . . . | $$ | . . # . . # . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . # . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . Q . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 1 . . . . . . . . . . . . . . | $$ | . . . B . P . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Sevis · Post by **Sevis** » Wed Feb 23, 2011 11:19 am

I may be giving white too much influence, but I think I still like the situation so far. I'm currently considering:

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . b . a . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . c . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

a is certainly first instinct, but it gives white a reason to build influence on the outside, which is certainly bad...

b does most to secure the corner, but it's very gote and not currently necessary.

c threatens to escape to the right, but strengthens the white stone.

Thus, a looks best in this area. Hm.

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . 8 . . . . . . . . . . X . . | $$ | . . . . 4 7 9 . . . . . . . . . . . . | $$ | . . . . 3 5 6 . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I expect white to push me to the right, trying to keep both sides strong.

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O 6 9 . . . . . . . . . . X . . | $$ | . . . . 5 4 . . . . . . . . . . . . . | $$ | . . . . 3 7 8 . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$Wcm32 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . 3 . . . . . . . . . . . . . | $$ | . . O O O 1 . . . . . . . . . . X . . | $$ | . . . . X O 2 . . . . . . . . . . . . | $$ | . a c . X X O . . . . . . . . . . . . | $$ | . b . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Here, whit ends up split, and the top stones are weak... He can jump lower and try to make a base, but I think I have some chance of killing at least a part of it.

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

topazg · Post by **topazg** » Wed Feb 23, 2011 12:10 pm

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . 4 . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

topazg · Post by **topazg** » Wed Feb 23, 2011 1:49 pm

Sevis, I've unhidden #40, #43, and #46

Sevis · Post by **Sevis** » Wed Feb 23, 2011 6:21 pm

First of all, sorry if I'm playing too slowly.

As far as I can see from one of the unhiddens, allowing you to play F7 was a horrible idea and I will likely lose something because of it. I am guessing that I will lose sente, but the corner might follow, too.

Now, to choose between the main two issues: start a fight or tenuki.

Click Here To Show Diagram Code: [go]$$Bcm24 Prisoner Count: B-0 W-0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . O . . . . . . . . . . . . | $$ | . . O O . O . . . . . . . . . O O . . | $$ | . X O X X . . X . , . . . O . X . . . | $$ | . . X . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . 2 O . 4 . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 5 6 . . . . . . . . . . . . | $$ | . . . X . O 7 9 . , . . . . . X . . . | $$ | . . . . . . 8 . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I wonder if this would play out anything like this. The white stone is too high to really do anything about, but it still feels like I should try cutting. I could push down on the left and then crawl on the fourth line for a little -- the two stones will live, but I'll get some influence... That's if white allows it, of course, which seems very unlikely.

Will think more before playing.

topazg · Post by **topazg** » Wed Feb 23, 2011 6:23 pm

@sevis:

EdLee · Post by **EdLee** » Thu Feb 24, 2011 4:30 am

Unhidden after :w27:

: Posts 18, 24, 39, 41, 42, 45, 48, 52, 59, 62.

topazg · Post by **topazg** » Thu Feb 24, 2011 5:09 am

@Ed:

I must admit, some of your posts and conclusions have gotten me intrigued and a bit surprised. Three of which I'm interested in asking about:

1) Four weak groups (post #39):

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 3 . Q . . . . . . . . . O O . . | $$ | . . Q X . . . X . , . . . O . X . . . | $$ | . . 2 . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . 4 . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . B . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . Q . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . a . . . . . . . . . . . . . . | $$ | . . . X . Q . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Here, you claim White has 4 weak groups, and that the marked Black stone isn't particularly weak. I've added :w4:

because I think it's the only reasonable move for White to take with his sente, and I'm curious - a) why do you consider the top White stone a group (it's more a dead stone with aji now), b) why do you consider White's top left group weak (it's got one and a half eyes with miai of 2 or center access), c) and why do you think Black's stone at D10 is not weak. The "4 weak groups" point sounds a bit like the misconception that every stone is important enough to save, and I find it hard to see how Black is going to easily settle D10. It's particularly hard for Black to play "a" here without harming D10.

2) The crosscut corner (post #45):

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 8 6 7 . . . . . . . . . . . . . . | $$ | . . 1 2 5 W . . . . . . . . . O O . . | $$ | . 4 O X . . . X . , . . . O . X . . . | $$ | . . . 3 . X . . . . . . . . . . X . . | $$ | . . a . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 9 . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Here, much to my surprise you claim White's corner shape in the top left is broken. White is unconditionally alive, and equally importantly Black has no sente move capable of sealing White in, therefore "a" has a reasonable chance of being White's sente (to ensure that D10 remains strong). Furthermore, the aji of the marked White stone is relatively high. The shape is also very similar to a typical 3-4 approach joseki misplay:

Click Here To Show Diagram Code: [go]$$B Normal $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . W . . . . . . . . . . . O O . . | $$ | . . 4 . . . . . . , . . . O . X . . . | $$ | . . 2 1 . . . . . . . . . . . . X . . | $$ | . . 3 5 . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$B Good for White - same shape as in proposed game variation $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . W . . . . . . . . . . . O O . . | $$ | . 8 3 4 . . . . . , . . . O . X . . . | $$ | . 6 2 1 . . . . . . . . . . . . X . . | $$ | . 7 5 . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Obviously in the last diagram White's a line higher, which is a "good thing" (with respect to points, at least), but I find it hard to persuasively argue that the shape itself is broken. Why do you consider this a bad result for White?

3) The other crosscut corner (post #45):

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . 5 . . . . . . . . . . . . . . . | $$ | . 2 3 O 1 . . . . . . . . . . . . . . | $$ | 4 X X O X O . . . . . . . . . O O . . | $$ | . O O X . . . X . , . . . O . X . . . | $$ | . . . X . X . . . . . . . . . . X . . | $$ | . . O . . . . . . . . . . . . X O . . | $$ | . . . b . a . . . . . . . . . O X . . | $$ | . . 6 . . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . O . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

When you state that Black has a big corner, I'm guessing you overlooked the above continuation, and after :w6:

(EDIT: Moved from "b" to somewhere better!) D10 is most definitely less stable, and White is becoming relatively hard to attack. I think it would be difficult for Black to justify White getting to play with "a", so I'm not really convinced Black can consider this definitely sente either. Despite this, I suspect this may have been Black's severest continuation (although the current result is interesting enough due to the increased stability of the left side), and I'd hinted I think in one of my variations that this is the route I expected things to take, but I'd still be satisfied enough at White to have Black expend so many stones for not that many points, and still have enough problems on the left to give White a lot of leverage to work with. Why do you consider White to have lost so much ground here?

EdLee · Post by **EdLee** » Thu Feb 24, 2011 7:16 am

@topazg:

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . e . . . . . . . . . . . | $$ | . . 1 3 . P . d . . . . . . . O O . . | $$ | . . Q X b . c X . , . . . O . X . . . | $$ | . . 2 . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X @ . . | $$ | . . . . . . . . . . . . . . . @ X . . | $$ | . . 4 . . . . . . . . . . . . . X . . | $$ | . f . . . . . . . . . . . . . . . . . | $$ | . . . B . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . Q . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . a . . . . . . . . . . . . . . | $$ | . . . X . Q . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

topazg wrote:a) why do you consider the top White stone a group (it's more a dead stone with aji now),

You're right about :wx:

-- I was going to refer to it as "group/dying/almost dead with aji,"
but I did not know how without making the sentence very cumbersome.
Besides, with the level difference, we never know what might happen
if W decides to try (b)...(e) etc. So for brevity I chose the few words.

topazg wrote:b) why do you consider White's top left group weak (it's got one and a half eyes with miai of 2 or center access)

If I was playing B, I'd consider any W group that's too big to let die but not completely settled "weak."
I'd certainly keep an eye on it, as would W, especially if B can get a move like (f) --
yes, W has access to the center, but if W needs to run, it means B may profit from the chase, too.
Having said that, it's possible that group is not weak. Maybe my judgment is wrong.

topazg wrote:c) and why do you think Black's stone at is not weak.
The "4 weak groups" point sounds a bit like the misconception that every stone is important enough to save,
and I find it hard to see how Black is going to easily settle .
It's particularly hard for Black to play "a" here without harming .

Of course not every stone is important, as :ws:

were not mentioned.

is clearly not weak to me, and B does not even need to settle it.
It is there to split and attack W. I don't see how B (a) would hurt :bc:

--
perhaps you can show a variation?

EdLee · Post by **EdLee** » Thu Feb 24, 2011 7:35 am

@topazg:

topazg · Post by **topazg** » Thu Feb 24, 2011 7:41 am

@Ed:

EdLee wrote:@topazg:
:bc: is clearly not weak to me, and B does not even need to settle it.
It is there to split and attack W. I don't see how B (a) would hurt --
perhaps you can show a variation?

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X . . . . . . . . . . . O O . . | $$ | . . O X . . . X . , . . . O . X . . . | $$ | . . O . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . O . a . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . , . . . | $$ | . . . . . . 0 . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . 2 6 9 . . . . . . . . X . . | $$ | . . . . . . 5 7 . . . . . . . . . . . | $$ | . . . . 1 3 . . . . . . . . . . . . . | $$ | . . . X . O 4 . 8 , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

At the moment, the more Black tries to push through these stones, the more he is inclined to force White to run into the middle. As the White stones at the bottom will be very hard to attack I think, the development of this sort of position suddenly makes D10 start to squirm. Now White moves like "a" start to become genuinely threatening to my eyes, and Black _must_ settle D10 to avoid giving White a very large left hand side. As a result, I'd choose to settle D10 first as Black, so that I can split in a way that allows an attack against White's stones in the lower left to keep up momentum. As it is, I think Black choosing to block on the side he did (something I hadn't considered very seriously if I'm honest) has meant that Black can now split in the lower left much more strongly. Of course, he's had to lose a _lot_ of points at the top, and it's hard to see how he can get compensation for that without killing something. This sort of thought process is precisely why I chose the funny contact rather than the 3-3 invasion .. if I get life in the corner here, it's just bigger, with some great follow up moves (like J17), then if I take the 3-3 (where I think Black gets to completely seal in in sente) - I had figured he'd therefore have to trade, and I hoped to use the potential for long term attacks on the left side to give the sequence value.

I'm still rather unsure whether the top left was correctly timed at all. F6 is clearly a really big move at that stage in the game, but unfortunately I couldn't see any really severe followups against the corner because of the rather loose nature of the double approach. The 3-3 didn't seem to work, and the contact plays certainly don't seem to. If I play F6 without severe followup, I figure a move like C16 or D17 by Black gives a huge amount of almost guaranteed points unless there's some really cunning invasions I don't see (and considering how tricky this one was, having an iron post up there seems to make it a bit of a fortress for Black).

If I was a betting man with a time machine, I'd probably take F6 on the return, and take sente again if Black takes that top left corner, perhaps to approach the lower right. However, until I feel more sure that F6 would turn itself into actual points at some stage (or kill the Black corner if he tenukis), I'm not particularly persuaded by either option over the other.

@Ed(2):

EdLee wrote:@topazg:
topazg wrote:much to my surprise you claim White's corner shape in the top left is broken.
When B pushes through with , W gets a broken shape by definition.

is broken off and severely damaged:
$$B
$$ -------------------
$$ | . . . . . . . . .
$$ | . . O Q B . . . .
$$ | . . X Q # W . . .
$$ | . O O # . . . X .
$$ | . . . # . X . . .
$$ | . . . . . . . . .

Click Here To Show Diagram Code
[go]$$B $$ ------------------- $$ | . . . . . . . . . $$ | . . O Q B . . . . $$ | . . X Q # W . . . $$ | . O O # . . . X . $$ | . . . # . X . . . $$ | . . . . . . . . .[/go]
The term broken shape or cracked shape comes from the Chinese 裂形.
Other languages may use different terminologies:
http://senseis.xmp.net/?LameDuGo
http://senseis.xmp.net/?SmallGaps

EdLee · Post by **EdLee** » Thu Feb 24, 2011 7:52 am

@topazg:

topazg · Post by **topazg** » Thu Feb 24, 2011 8:03 am

EdLee wrote:@topazg:
topazg wrote:
$$B
$$ -------------------
$$ | . . . . . . . . .
$$ | . . 8 6 7 . . . .
$$ | . . 2 3 9 W . 1 .
$$ | . . 4 X . . . . .
$$ | . . . 5 . . . . .
$$ | . . 0 . . . . . .

Click Here To Show Diagram Code
[go]$$B $$ ------------------- $$ | . . . . . . . . . $$ | . . 8 6 7 . . . . $$ | . . 2 3 9 W . 1 . $$ | . . 4 X . . . . . $$ | . . . 5 . . . . . $$ | . . 0 . . . . . .[/go]
Would you likewise consider this to be bad for White because is broken off from the corner?
It's a classic "broken shape" after , but it's also joseki for a reason.
Not all broken shapes are bad. Just like not all empty triangles are bad.
Sometimes a broken shape or an empty triangle is a top pro move.

EdLee · Post by **EdLee** » Thu Feb 24, 2011 2:51 pm

@topazg:

topazg wrote:Now White moves like "a" start to become genuinely threatening to my eyes,
and Black _must_ settle to avoid giving White a very large left hand side.
$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X X . . . . . . . . . . . O O . . |
$$ | . . O X . . . X . , . . . O . X . . . |
$$ | . . O . . X . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . O . a . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . B . . . . . , . . . . . , . . . |
$$ | . . . . . . 0 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . 2 6 9 . . . . . . . . X . . |
$$ | . . . . . . 5 7 . . . . . . . . . . . |
$$ | . . . . 1 3 . . . . . . . . . . . . . |
$$ | . . . X . O 4 . 8 , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X . . . . . . . . . . . O O . . | $$ | . . O X . . . X . , . . . O . X . . . | $$ | . . O . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . O . a . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . B . . . . . , . . . . . , . . . | $$ | . . . . . . 0 . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . 2 6 9 . . . . . . . . X . . | $$ | . . . . . . 5 7 . . . . . . . . . . . | $$ | . . . . 1 3 . . . . . . . . . . . . . | $$ | . . . X . O 4 . 8 , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

I added

back.

in your var was loose. How about this--
W would not get a chance to play (a). If anything, it's B who gets to play either (a) to close W,
(b) to chase W out. W is under attack. B has no need to settle :bc:

because
B is actively attacking, and also because the left side has very few points (for both B and W):

Click Here To Show Diagram Code: [go]$$B $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X X . W . . . . . . . . . O O . . | $$ | . . O X . . . X . , . . . O . X . . . | $$ | . . O . . X . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . . O X . . | $$ | . . O . a . . . . . . . . . . . X . . | $$ | . b . . . . . . . . . . . . . . . . . | $$ | . . . B . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . 3 . . 9 . . . . . . . . . . . | $$ | . . . O 4 O . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . X X 1 5 7 . . . . . . . . . . | $$ | . . . X . O O 2 . 6 . . . . . X . . . | $$ | . . . . . . . . . . 8 . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Life In 19x19

99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re: 99. topazg vs sevis

Re:

Re: