While trying to solve a problem, the following diagram arised (black to move):
Which is a better move for Black - A or B, and why?
(This kind of difference can be found in many other situations.)
which is a better move in this position?
-
p2501
- Lives in gote
- Posts: 598
- Joined: Tue Jul 26, 2011 8:25 am
- Rank: 4 kyu
- GD Posts: 0
- Universal go server handle: p2501
- Location: Germany, Berlin
- Has thanked: 331 times
- Been thanked: 101 times
Re: which is a better move in this position?
Just looking at it I'd say B is the only move.
edit: Forgot to tell why:
A) Gives white to much forcing moves. Don't like the shape.
B) More liberties. Puts severe pressure on the bottom left stones. Reserving which side to atari from seems good.
edit: Forgot to tell why:
A) Gives white to much forcing moves. Don't like the shape.
B) More liberties. Puts severe pressure on the bottom left stones. Reserving which side to atari from seems good.
Last edited by p2501 on Fri Dec 14, 2012 6:39 am, edited 1 time in total.
-
Alguien
- Lives in gote
- Posts: 628
- Joined: Tue Aug 07, 2012 11:50 pm
- Rank: KGS 3k
- GD Posts: 0
- Universal go server handle: Alguien
- Has thanked: 44 times
- Been thanked: 93 times
Re: which is a better move in this position?
My reasoning:
- the bottom b group has 3 libs.
- the one next to it has also 3 libs.
- whoever starts removing libs wins, if he can keep removing them.
- can I pull off putting a stone on the point under B, to remove a lib from W?
- I read it as a yes:
- option 1: w ataris my stone, I extend to 'B', he extends to not die, I capture bottom.
- option 2: w extends bottom, I play 'A' and capture w on a net (or he tries to escape net and I kill the now three stone bottom group).
(paint your problem as a usual (go) diagram and I'll paint my moves on it, if you want)
[edit: ok, ok ,I'll paint it:]
- the bottom b group has 3 libs.
- the one next to it has also 3 libs.
- whoever starts removing libs wins, if he can keep removing them.
- can I pull off putting a stone on the point under B, to remove a lib from W?
- I read it as a yes:
- option 1: w ataris my stone, I extend to 'B', he extends to not die, I capture bottom.
- option 2: w extends bottom, I play 'A' and capture w on a net (or he tries to escape net and I kill the now three stone bottom group).
(paint your problem as a usual (go) diagram and I'll paint my moves on it, if you want)
[edit: ok, ok ,I'll paint it:]
-
SoDesuNe
- Gosei
- Posts: 1810
- Joined: Wed Apr 21, 2010 1:57 am
- Rank: KGS 1-dan
- GD Posts: 0
- Has thanked: 490 times
- Been thanked: 365 times
Re: which is a better move in this position?
It's B in this situation.
Alguien: White plays
here and has a really good result.
post scriptum:
I should get some rest... Forget what I edited :X
Alguien: White plays
here and has a really good result.post scriptum:
I should get some rest... Forget what I edited :X
-
peppernut
- Dies in gote
- Posts: 63
- Joined: Tue Oct 09, 2012 4:51 am
- Rank: 5k
- GD Posts: 0
- KGS: peppernut
- Has thanked: 12 times
- Been thanked: 21 times
Re: which is a better move in this position?
White has two groups of cutting stones. Looks to me like move B makes miai out of a and b, and one of the groups is going to die.
Move A drives the triangle group over your own cutting stone, and forces its capture, but Black gets guaranteed influence. If playing B and capturing the low group is unsatisfying, then okay, play A. But that's basically 5th line territory that you're giving up. Not seeing the rest of the board, I think it's clearly better to fight to kill one of the two white groups.
Move A drives the triangle group over your own cutting stone, and forces its capture, but Black gets guaranteed influence. If playing B and capturing the low group is unsatisfying, then okay, play A. But that's basically 5th line territory that you're giving up. Not seeing the rest of the board, I think it's clearly better to fight to kill one of the two white groups.
-
topazg
- Tengen
- Posts: 4511
- Joined: Wed Apr 21, 2010 3:08 am
- Rank: Nebulous
- GD Posts: 918
- KGS: topazg
- Location: Chatteris, UK
- Has thanked: 1579 times
- Been thanked: 650 times
- Contact:
Re: which is a better move in this position?
White has no such capture ... the extension at 
seems best to me.
seems best to me.-
Uberdude
- Judan
- Posts: 6727
- Joined: Thu Nov 24, 2011 11:35 am
- Rank: UK 4 dan
- GD Posts: 0
- KGS: Uberdude 4d
- OGS: Uberdude 7d
- Location: Cambridge, UK
- Has thanked: 436 times
- Been thanked: 3718 times
Re: which is a better move in this position?
I don't know the answer to that problem, though probably A is best as they both work and A asks white to make a heavy group in bad shape before capturing the side stones, whereas if white gets to nobi there his shape is better and the black group to the right could be attacked.
Also in that sort of shape sometimes the m2 clamp is the only move fast enough.
P.S. In topazg's diagram although black captures the outside stones which is great white does have a 1st line connection for later which he doesn't with the atari. If black is trying to make territory to the left side that could be quite significant.
Also in that sort of shape sometimes the m2 clamp is the only move fast enough.
P.S. In topazg's diagram although black captures the outside stones which is great white does have a 1st line connection for later which he doesn't with the atari. If black is trying to make territory to the left side that could be quite significant.
-
Loons
- Gosei
- Posts: 1378
- Joined: Tue Apr 20, 2010 4:17 am
- GD Posts: 0
- Location: wHam!lton, Aotearoa
- Has thanked: 253 times
- Been thanked: 105 times
Re: which is a better move in this position?
My feeling was that 'a' is right, but now I'm not sure.
I think I overthought this.
Also this:
Also this:
-
speedchase
- Lives in sente
- Posts: 800
- Joined: Sun Dec 04, 2011 4:36 pm
- Rank: AGA 2kyu
- GD Posts: 0
- Universal go server handle: speedchase
- Has thanked: 139 times
- Been thanked: 122 times
Re: which is a better move in this position?
this is Terrible for black!SoDesuNe wrote:It's B in this situation.
Ladder is the correct move
-
tj86430
- Gosei
- Posts: 1348
- Joined: Wed Apr 28, 2010 12:42 am
- Rank: FGA 7k GoR 1297
- GD Posts: 0
- Location: Finland
- Has thanked: 49 times
- Been thanked: 129 times
Re: which is a better move in this position?
There is an extra black stone in your diagram.speedchase wrote: Ladder is the correct move
Offending ad removed
-
SoDesuNe
- Gosei
- Posts: 1810
- Joined: Wed Apr 21, 2010 1:57 am
- Rank: KGS 1-dan
- GD Posts: 0
- Has thanked: 490 times
- Been thanked: 365 times
Re: which is a better move in this position?
Yes, I had edited my post multiple times and everytime I found another mistake. Wasn't my day - sorry ^^speedchase wrote:this is Terrible for black!SoDesuNe wrote:It's B in this situation.
Ladder is the correct move
-
Bill Spight
- Honinbo
- Posts: 10905
- Joined: Wed Apr 21, 2010 1:24 pm
- Has thanked: 3651 times
- Been thanked: 3373 times
Re: which is a better move in this position?
For a while I thought that might be the preferable way to capture (on an otherwise empty board), because the side is bigger than either the corner or center.
However,
pretty well forces 
, now or in the next few moves.
This way is better for Black.
In both cases should be gote on an empty board, however.
But if
is gote, it leaves behind 
, a nice yose.
So now I am leaning to the atari.
OC, if there are stones to the left, that matters greatly.
might be the preferable way to capture (on an otherwise empty board), because the side is bigger than either the corner or center.However,
pretty well forces , now or in the next few moves.This way is better for Black.
In both cases
should be gote on an empty board, however.But if
is gote, it leaves behind , a nice yose.So now I am leaning to the atari.
OC, if there are stones to the left, that matters greatly.
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
At some point, doesn't thinking have to go on?
— Winona Adkins
Visualize whirled peas.
Everything with love. Stay safe.
-
peppernut
- Dies in gote
- Posts: 63
- Joined: Tue Oct 09, 2012 4:51 am
- Rank: 5k
- GD Posts: 0
- KGS: peppernut
- Has thanked: 12 times
- Been thanked: 21 times
Re: which is a better move in this position?
What I don't get is if you're going to do this, why exchange the marked stone for
? Why not 
directly?This line gets complicated. There is a white group cutting 3 black groups, only one of which is strong. I am having trouble seeing why capturing some white stones, connecting your groups, and leaving white with the only weak group isn't clearly right. Yet überdude also likes this move, so there has to be merit to this move that I'm not understanding. Can you explain it?
-
MMaestro
- Dies in gote
- Posts: 43
- Joined: Tue Sep 20, 2011 12:19 am
- Rank: AGA 3D
- GD Posts: 0
- KGS: 2D
- Tygem: 6D
- Been thanked: 16 times
Re: which is a better move in this position?
Depending on the rest of the board, the clamp can also be a viable option if you really don't want white to connect his left side stones to the right side.
-
gogameguru
- Lives in gote
- Posts: 477
- Joined: Sun Jan 09, 2011 9:18 pm
- Rank: 5d
- GD Posts: 0
- Has thanked: 192 times
- Been thanked: 357 times
- Contact:
Re: which is a better move in this position?
This is an excellent question and it's worth spending some time pondering it.
@peppernut
Playing the atari first wins hands down in this case. It's simply better technique.
That's because it creates better shape after capturing the stones, because makes white heavy before 'defending', because it slows white's future development and because it still creates miai. However, the answer to this question can change depending on the position. That's Go for you.
Here are some less settled (fictitious) positions to illustrate these points more clearly. Assume the ladder favors black in all cases.
Black has gained a little extra time to move here, because of the exchange of 1 for 2. If 6 is at 'e', black still plays 7.
[Updated and fixed mistake where I kept saying white instead of black. Thanks friendly editor
]
(note: 5 is better than 'a' for fighting here. Play 5 when you expect fighting in the center. Now 'b' isn't sente, but 'c' is sente instead and 'd' is sente in either case.)
Now 'a' and 'b' are miai for black and white's too thin to fight like this. Note that if white cuts at 'a' and black extends to 'b', white's cutting stones are captured. However, if black had played 'c' instead of 5 earlier, white would be able to escape with 'd' and black would be in trouble. This illustrates the subtle difference between those two moves. A lot of people think 5 looks less stylish, but it's the fighting move.
Now let's consider another position:
Based on the previous diagrams, you might think that this is a good way for black to play, and you'd be right.
However, note that white's corner is unsettled. If you like to fight, there's another way to play here.
Sacrificing 1 costs black something and strengthens white's four stone group (which has to be considered because it diminishes the value of separating white in the first place). However, it can't be denied that white's groups have been separated and white will have to make four eyes instead of two now. Black's shape is worse now too.
This is a fighting variation which can be good if the global position supports this sort of strategy.
Here's one final example:
Years ago, I remember I thought for a little while that this situation was basically the same as in the examples above
, but...
It's not.
White can play a makeshift defense with 4, then play 6, and black practically collapses. All black can do now is try desperately to recover with a squeeze at 'a'. It might be good enough to keep playing for awhile, but it doesn't really work well enough. Black lost a lot here.
@peppernut
That's because it creates better shape after capturing the stones, because makes white heavy before 'defending', because it slows white's future development and because it still creates miai. However, the answer to this question can change depending on the position. That's Go for you
.Here are some less settled (fictitious) positions to illustrate these points more clearly. Assume the ladder favors black in all cases.
Black has gained a little extra time to move here, because of the exchange of 1 for 2. If 6 is at 'e', black still plays 7.
[Updated and fixed mistake where I kept saying white instead of black. Thanks friendly editor
](note: 5 is better than 'a' for fighting here. Play 5 when you expect fighting in the center. Now 'b' isn't sente, but 'c' is sente instead and 'd' is sente in either case.)
Now 'a' and 'b' are miai for black and white's too thin to fight like this. Note that if white cuts at 'a' and black extends to 'b', white's cutting stones are captured. However, if black had played 'c' instead of 5 earlier, white would be able to escape with 'd' and black would be in trouble. This illustrates the subtle difference between those two moves. A lot of people think 5 looks less stylish, but it's the fighting move.
Now let's consider another position:
Based on the previous diagrams, you might think that this is a good way for black to play, and you'd be right.
However, note that white's corner is unsettled. If you like to fight, there's another way to play here.
Sacrificing 1 costs black something and strengthens white's four stone group (which has to be considered because it diminishes the value of separating white in the first place). However, it can't be denied that white's groups have been separated and white will have to make four eyes instead of two now. Black's shape is worse now too.
This is a fighting variation which can be good if the global position supports this sort of strategy.
Here's one final example:
Years ago, I remember I thought for a little while that this situation was basically the same as in the examples above
, but...It's not.
White can play a makeshift defense with 4, then play 6, and black practically collapses. All black can do now is try desperately to recover with a squeeze at 'a'. It might be good enough to keep playing for awhile, but it doesn't really work well enough. Black lost a lot here.
Last edited by gogameguru on Sun Dec 16, 2012 5:52 am, edited 1 time in total.