I don't really understand why he plays this now, since it looks very small to me. However, I still think I need to answer to keep my group safe. Even if it could live if I tenuki, I don't want it to become a target later.
Posted: Wed Jul 27, 2011 3:01 pm
by EdLee
(For beginners, mostly.) ( ) was gote -- the group can get out very easily with (a), (b), etc. So B could and should have tenuki'd: is very severe:
This is not really true, I think. looks small and gote, but in fact it is big, because it destroys blacks eye-space. I would have played the same move. The marked black stones are now target for attack. Furthermore, is probably a mistake, which is now being "punished" by . Instead, black could have played like this, which is much more solid:
$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . W X . . X . O . . . . . . . O O O . | $$ | . O . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |
[go]$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . W X . . X . O . . . . . . . O O O . | $$ | . O . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]
Also some words on the bottom right corner. The two white stones there cannot be attacked as long as the black corner is still open. White easily dodges blacks attack by simply sacrifing his stones:
Look at how overconcentrated all of the black stones are now! This is why the marked black stone was in the wrong direction. It doesn't add much to blacks upper right territory, and the white group is not really attackable as long as the corner is still open. It would be much better, both in terms of points and in terms of pressure on white, to move from the other side:
This is not really true, I think. looks small and gote, but in fact it is big, because it destroys blacks eye-space. I would have played the same move. The marked black stones are now target for attack. Furthermore, is probably a mistake, which is now being "punished" by . Instead, black could have played like this, which is much more solid:
$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . W X . . X . O . . . . . . . O O O . | $$ | . O . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |
[go]$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . W X . . X . O . . . . . . . O O O . | $$ | . O . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]
I agree with you, this would have been my move, and for exactly the same reasoning. I was actually wondering whether I would probably have responded there a couple of moves earlier actually:
$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |
[go]$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]
Re: Re:
Posted: Thu Jul 28, 2011 10:09 am
by gaius
@topazg:
topazg wrote:I agree with you, this would have been my move, and for exactly the same reasoning. I was actually wondering whether I would probably have responded there a couple of moves earlier actually:
$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |
[go]$$B Also solid, but takes points too. $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . 1 X . . . . . , . . . O O X X O . | $$ | . . . . . . . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]
Re: Re:
Posted: Thu Jul 28, 2011 11:10 am
by topazg
gaius wrote:@topazg:
topazg wrote:I agree with you, this would have been my move, and for exactly the same reasoning. I was actually wondering whether I would probably have responded there a couple of moves earlier actually:
$$B More solid $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . . X . . . . . , . . . O O X X O . | $$ | . . . . . 1 . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |
[go]$$B Also solid, but takes points too. $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . W . . . . . . . O O O . | $$ | . . 1 X . . . . . , . . . O O X X O . | $$ | . . . . . . . . . . . . . . X X . X . | $$ | . . O . . . . . . . . . . . . . O X . | $$ | . . . . . . . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . |[/go]
Interesting - my justification is that it makes miai of pincering and attacking one of the two White stones. I figure taking points and letting White protect one side (probably the left) was too generous - you feel it's worth the cash at this point?
Posted: Thu Jul 28, 2011 11:25 am
by EdLee
gaius, topazg:
I still feel is gote. As for the lower right being "over-concentrated" for B, let's look at a bigger picture of the right side: W gets only about 10 points in the lower right corner, in gote. In the meantime, B gets 40+ points alone in cash, and B still has time to get back to (a) later, if needed. Plus, B's immense thickness on the right means W will make very little on the left (b) areas.
I feel like this is a case of urgent before big. White has the advantage of being able to handle the bottom right lightly, which means it's hard for Black to punish really severely. The top left, White can turn into a floating group if he tenukis, by playing at F15 for example, and Black has no light way to handle his group. Ignoring again will eventually result in a dead corner, which means White gets to seal in and locally keep sente. That's a really painful result for White.
Also, your 40-10 point comparison I'm not sure is valid, as part of Black's value there depends on the top right, where White also has points. Considering this started as a 4 stone handicap game, Black's spent 17 stones and picked up maybe 40-50 points, and White's spent 14 stones and picked up ~20-25 points. That's actually a pretty good deal, considering White's got those extra 3 moves to throw around the rest of the board. I would agree with Gaius that this feels overconcentrated for Black.
There's also the issue that White has no dead easy way of settling those two stones in the lower right anyway, as running out allows Black to profit along the bottom edge. I would even go so far as to suggest that punishing those two stones is better achieved with a move around K3, building from both corners and making your second variation even more profitable.
I think Kirby made a slight error in jumping out at all down there, just to tenuki the next move - I don't think the temperature had dropped enough. However, having tenuki'd to the top left, I think responding there was more urgent than following up in the lower right, and I certainly think (with regards to the top left) that either a) being sealed in, or b) being forced to run out without eyes are worse results for Black than the positive result that can be managed in the lower right.
Just by 2c/2p anyway
Posted: Thu Jul 28, 2011 12:14 pm
by EdLee
topazg:
Yes, the 4 handicap stones do allow some slack moves for B and B can still come out OK globally. Let me double check and get back to you.
( 
) was gote -- the 
group can get out very easily with (a), (b), etc.
is very severe:
is probably a mistake, which is now being "punished" by 
. Instead, black could have played like this, which is much more solid:
As for the lower right being "over-concentrated" for B, let's look at a bigger picture of the right side: