pincer question

emeraldemon · Post by **emeraldemon** » Fri Mar 04, 2011 9:41 am

This position came up in one of my games. I played white. How should white respond to the cut at 3?

Click Here To Show Diagram Code: [go]$$Bcm1 knight's move after pincer $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X 2 . . | $$ | . . . X . . . . . , . . . 1 . , 3 . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

This is how it went in my game:

Click Here To Show Diagram Code: [go]$$Bcm1 Moves 7 to 16 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . 0 . . | $$ | . . . . . . . . . . . . . . . X O 9 . | $$ | . . . X . . . . . , . . . X . 4 X . . | $$ | . . . . . . . . . . . . . . . O 5 . . | $$ | . . . . . . . . . . . . . . . 8 6 7 . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$Bcm11 Moves 17 to 21 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O 4 . | $$ | . . . . . . . . . . . . . . . . O 3 . | $$ | . . . . . . . . . . . . . . 2 X O X . | $$ | . . . X . . . . . , . . . X . O X . . | $$ | . . . . . . . . . . 5 . . . . O X . . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . 1 . | $$ ---------------------------------------[/go]

I was unhappy with this result, because it seems like :b15:

makes white's thickness mostly useless, and black gets territory in compensation. Is there a better way to play it?

amnal · Post by **amnal** » Fri Mar 04, 2011 9:55 am

I played with the sequence a bit, but I do not see a place where either player can depart from it with good results.

I think the result is actually okay for you. Black gets nothing in the corner, and white still has a forcing move or two against it (at the very least, the descent seems to be sente for white). As well as this, black's 'erasing' move seems a bit rubbish - if you pincer at some point, it becomes a weak group without a good extension and the wall is working well. I'm inclined to say that black has played too close to thickness.

This position is hard to use, but I think it is easy to be over-pessimistic about just how hard - black has made you a great wall. He has semi-erased one side of it, but the other side is equally powerful and unaffected. In return, black gets about 3 points of corner territory, and a semi-weak group.

daniel_the_smith · Post by **daniel_the_smith** » Fri Mar 04, 2011 10:23 am

When I read the phrase "I was unhappy with this result..." I thought you must be playing black... I'd much rather have white on that board. White has sente and black's formation seems inefficient and awkwardly placed. O4 is almost completely worthless.

Post by **Joaz Banbeck** » Fri Mar 04, 2011 11:18 am

Click Here To Show Diagram Code: [go]$$Bcm11 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O 4 . | $$ | . . . . . . . . . . . . . . . . O 3 . | $$ | . . . . . . . . . . . . . . 2 X O X . | $$ | . . . X . . . . . , . . . X . O X . . | $$ | . . . . . . . . 6 . 5 . . . . O X . . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . 1 . | $$ ---------------------------------------[/go]

I think that you are doing just fine. I'd play :w16:

and push those weak stones against the wall that black has so kindly forced you to build.

EDIT: I never would have played :w14:

so soon. It is gote for you. If he wants it, let him have it. You can be perfectly happy marching along with him, you making a strong wall on the 3rd line while he makes a pittance by crawling on the 2nd.

Click Here To Show Diagram Code: [go]$$Bcm11 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . 8 . . | $$ | . . . . . . . . . . . . . . . . 6 7 . | $$ | . . . . . . . . . . . . . . . . O 5 . | $$ | . . . . . . . . . . . . . . . . O 3 . | $$ | . . . . . . . . . . . . . . 2 X O X . | $$ | . . . X . . . . . , . . . X . O X . . | $$ | . . . . . . 4 . . . . . . . . O X . . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . 1 . | $$ ---------------------------------------[/go]

( Caveat: I do not claim that the exact placement of :w14:

in the above diagram is best. It is intended to illustrate the idea of extending off of a wall. It also shows how little he can get by taking S7 when you don't. )

Dusk Eagle · Post by **Dusk Eagle** » Fri Mar 04, 2011 12:27 pm

I agree with the other commenters. I think :w14:

is too slow, but even so I would far prefer to be white on this board. Walls aren't instantly destroyed whenever the other color gets a move on the J, K, or L column. Your strong shape can influence the rest of the game just by existing.

Bill Spight · Post by **Bill Spight** » Fri Mar 04, 2011 1:23 pm

emeraldemon wrote:
$$Bcm11 Moves 17 to 21
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$$ | . . . . . . . . . . . . . . . . O 4 . |
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$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$Bcm11 Moves 17 to 21 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O 4 . | $$ | . . . . . . . . . . . . . . . . O 3 . | $$ | . . . . . . . . . . . . . . 2 X O X . | $$ | . . . X . . . . . , . . . B . O X . . | $$ | . . . . . . . . . . 5 . . . . O X . . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . 1 . | $$ ---------------------------------------[/go]

I was unhappy with this result, because it seems like makes white's thickness mostly useless, and black gets territory in compensation.

I agree with the others. :b13:

is not sente, but even so, White should be ecstatic.

As for Black's territory in compensation, the count in the corner is only 3 points. That is next to nothing.

Also, White's thickness is not mostly useless. Rather, :bc:

is an almost wasted stone. (If :b15:

were already in place, would Black play :bc:

next?) Now, I was taught that a wrap-around wall was worth 50 pts. Here Black has some aji, so it is worth somewhat less. Also, Black has reduced White's influence on the bottom side. Let's be generous to Black and say that the value of White's influence in the bottom right quadrant is only around 25 pts. IMO, White has gained more than one stone.

RobertJasiek · Post by **RobertJasiek** » Fri Mar 04, 2011 11:49 pm

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

Comparison:

- Black's plays 1 and 3 are not wasted because they are not too close to White's wall. In your game, Black loses quite some points by playing too close.
- In the lower right, Black gets ca. 6 points less in your game. Still Black's corner invasion is much too early and the White thickness is worth much more than Black's 9 points here.
- The exchange 5 - 6 is a loss: Black loses 1 point and the additional thickness for White is worth several points. It is, however, exactly what has happened in your game.

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

This is still a slight loss for Black but not such a desaster for him as in your game.

Conclusion:

- The white thickness is worth MUCH more than you thought.
- Black played too close to the white thickness.
- Black 1 in your game was a mistake.
- Black taking the corner in your game was a mistake.

SpongeBob · Post by **SpongeBob** » Sat Mar 05, 2011 1:16 am

Maybe it is possible to play for Ko?

Click Here To Show Diagram Code: [go]$$Wcm12 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . O 1 5 | $$ | . . . . . . . . . . . . . . . X O X 3 | $$ | . . . X . . . . . , . . . X . O X . 4 | $$ | . . . . . . . . . . . . . . . O X 2 . | $$ | . . . . . . . . . . . . . . . O O X 6 | $$ | . . . . . . . . . . . . . . . . . X . | $$ ---------------------------------------[/go]

Bill Spight · Post by **Bill Spight** » Sat Mar 05, 2011 1:29 am

SpongeBob wrote:Maybe it is possible to play for Ko?

$$Wcm12
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$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$Wcm12 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . O 1 5 | $$ | . . . . . . . . . . . . . . . X O X 3 | $$ | . . . X . . . . . , . . . X . O X . 4 | $$ | . . . . . . . . . . . . . . . O X 2 . | $$ | . . . . . . . . . . . . . . . O O X 6 | $$ | . . . . . . . . . . . . . . . . . X . | $$ ---------------------------------------[/go]

Click Here To Show Diagram Code: [go]$$Wcm12 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . O 1 3 | $$ | . . . . . . . . . . . . . . . X O X 2 | $$ | . . . X . . . . . , . . . X . O X . . | $$ | . . . . . . . . . . . . . . . O X 4 . | $$ | . . . . . . . . . . . . . . . O O X . | $$ | . . . . . . . . . . . . . . . . . X . | $$ ---------------------------------------[/go]

Edit: Corrected.

Life In 19x19

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