Positional judgement

lorill · Post by **lorill** » Fri Feb 25, 2011 6:28 am

Here's the position for a game, right after the first corner exchange.

Click Here To Show Diagram Code: [go]$$c Position at move 63, white to play $$ --------------------------------------- $$ | . O . X . X . X X . . . . . . . . . . | $$ | X O . . O O X . . X . . . . . . . . . | $$ | . X O O . X . X . X . . . . . . . . . | $$ | . X X O X X X X X O . . . . . X . . . | $$ | . O X X O X . . O O . . . . . . . . . | $$ | . O O X O O X O X . . . . . . . . . . | $$ | . . . O X O . X . . . . . . . . . . . | $$ | . . . O X . O . . . . . . . . . . . . | $$ | . . . O X . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . O . . . . . . . . . . . . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O , . . . . . , . . . . . , . . . | $$ | . . . . O . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In the review, my opponent and myself couldn't agree on the result.
What's your opinion on this position ? Better for black, for white, or even ?

Magicwand · Post by **Magicwand** » Fri Feb 25, 2011 6:47 am

black is better.
black is thicker.

reason:
they are pretty much equal but i dont like black aji in the middle.
i think white have to play there now orelse black will use that aji to get control of the middle.

again..it is my preference and other players might have different opinion and reason.
but i think most professionals will agree with my pick.

Phelan · Post by **Phelan** » Fri Feb 25, 2011 7:04 am

I also think black is better here. His stones seem to work better together.

HermanHiddema · Post by **HermanHiddema** » Fri Feb 25, 2011 7:04 am

I prefer black. Black has good aji in the center, I don't see any good way for white to prevent black from getting ahead in the center, even with sente.

lorill · Post by **lorill** » Fri Feb 25, 2011 7:10 am

It looks like there's a consensus and I'm the one wrong, then. I'll have to think a bit more about it I guess.

Bill Spight · Post by **Bill Spight** » Fri Feb 25, 2011 8:53 am

I also agree that Black is better.

But not by all that much. It is still a game, particularly at the kyu level.

daal · Post by **daal** » Fri Feb 25, 2011 9:06 am

lorill wrote:It looks like there's a consensus and I'm the one wrong, then. I'll have to think a bit more about it I guess.

Well, you're not alone. For me white was an easy pick. As white, I would play K4 and consider this a won game. I guess it goes to show that if you are strong enough to know how to use thickness, then you can recognize it's value.

RobertJasiek · Post by **RobertJasiek** » Fri Feb 25, 2011 9:26 am

Click Here To Show Diagram Code: [go]$$c White to play, prisoners - komi = 0 $$ --------------------------------------- $$ | . O . X . X . X X . . . . . . . . . . | $$ | X O . . O O X . . X . . . . . . . . . | $$ | . X O O . X . X . X . . . . . . . . . | $$ | O X X O X X X X X . . . . . . , . . . | $$ | . O X X O X . . . . . . . . . . . . . | $$ | . O O X O O X O X . . . . . . . . . . | $$ | . . . O . O . X . . . . . . . . . . . | $$ | . . . O . . O . . . . . . . . . . . . | $$ | . . . O . . . X . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Simplifying the position a bit, Black has ca. 8 and White has ca. 24. White has ca. 16 points more and sente. Black has ca. 5 stones more on the outside than White. This should be very easy for Black.

EDIT: The difference of prisoners (Black must have 7 more) and komi (I have guessed it as 7) appears to be 0. The other values are corrected accordingly.

The Pilgrim · Post by **The Pilgrim** » Fri Feb 25, 2011 12:22 pm

I agree, black is better

Well this game was a quick game (I'm the opponent of Lorill) and after the end of the corner sequence, I didn't felt bad but neither ahead. But I think white R14 corner approach wasn't good at all after this.

Edit : @Robertjasiek : what means "ca." ?

HermanHiddema · Post by **HermanHiddema** » Fri Feb 25, 2011 12:33 pm

@Robert: Where did the stone at H11 come from? Is that based on Black getting one move in the center in exchange for the aji of the (removes) E11/E12/E13 stones?

mitsun · Post by **mitsun** » Fri Feb 25, 2011 12:46 pm

OK, I will give a dissenting opinion. I think the game is still playable for both sides, and I would not mind taking W in this position. W has a considerable lead in secure territory. While it is true that B has superior thickness, W has sente now to do something about that. For example, W can make the beautiful shoulder hit at Q10 to negate much B center thickness. It also looks like an invasion at R17 can easily live, leaving B with very little territory.

Thanks lorill for presenting us with a great position to analyze, perfect for this forum. I would be really interested in hearing a definitive opinion from a professional.

RobertJasiek · Post by **RobertJasiek** » Fri Feb 25, 2011 2:38 pm

Herman, H11 is a sample exchange for A16, just to remind us that Black has one or two sente plays in the center.

Pilgrim, "ca." means ca. Easy:) For Black I have counted K19 and J15 1/2 each. For White, I have not counted D19 etc. but this is a simplification. It makes some sense because Black E19 threatens D18. So it is not just White who can make some territory there. I have counted E13 but not more points below there; this is also an approximation. So "ca." is pretty necessary.

RobertJasiek · Post by **RobertJasiek** » Fri Feb 25, 2011 2:41 pm

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

Such sequences come to one's mind but they are not impressive. White cannot even live in sente in the upper right.

oren · Post by **oren** » Fri Feb 25, 2011 2:59 pm

The Pilgrim wrote:Edit : @Robertjasiek : what means "ca." ?

Here you go.

http://en.wikipedia.org/wiki/Circa

daniel_the_smith · Post by **daniel_the_smith** » Fri Feb 25, 2011 3:17 pm

To me, it looks close but I would rather play black.

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