Opening problems for AI: Problem 48

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Bill Spight
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Opening problems for AI: Problem 48

Post by Bill Spight »

Black to play.

As always, assume komi.
Click Here To Show Diagram Code
[go]$$Bc Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 3 . . 6 . . 8 . . . 7 . . . . |
$$ | . . 2 , . . . . . , . . . . . , 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . 0 . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . 9 , . . . . . , . . . . . , . . . |
$$ | . . . . 5 . . . . . . . . . . b c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Which is best for Black, which is worst? a, b, or c?

Enjoy! :)
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Gomoto
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Re: Opening problems for AI: Problem 48

Post by Gomoto »

c
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jlt
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Re: Opening problems for AI: Problem 48

Post by jlt »

I didn't expect another answer from Gomoto-san(-san). According to LeelaZero's gospel, corners are usually more important than sides, and although the stone :b3: is a bit lonely, bots know how to handle these kinds of situations. Black takes the corner, White gets a wall but Black can play :b21: at "d" to make an ideal extension from the upper right shimari and cancel White's influence.

Click Here To Show Diagram Code
[go]$$Bcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . O . . O . . . X . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 4 O . . |
$$ | . . X , . . . . . , . 0 8 6 2 3 . . . |
$$ | . . . . X . . . . . . . 9 7 5 . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
On the other hand, as a human kyu player, I wouldn't feel too comfortable with my stone :b3: battling against four enemies. In addition, not caring about the lower right corner and letting White make a shimari there seems fine, as Black already has two shimaris.

A first idea would be to try to press down the stone :w2:, but White is probably strong enough to cut, and the fight will be favorable for White
Click Here To Show Diagram Code
[go]$$Bcm11 doesn't seem a good idea
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . O . . O . . . X . . . . |
$$ | . . O 2 3 . . . . , . . . . . , X . . |
$$ | . . . 1 4 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
A second idea would be to make a base first, but Black still looks weak with so many white stones around.
Click Here To Show Diagram Code
[go]$$Bcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . 2 1 . X . . O . . O . . . X . . . . |
$$ | . . O 3 . . . . . , . . . . . , X . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So maybe the shoulder hit is there to provide support for :b3:
Click Here To Show Diagram Code
[go]$$Bcm11 something like this?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 4 3 . X . . O . . O . . . X . . . . |
$$ | . . O 5 . . . . . , . . . . . , X . . |
$$ | . . 6 7 . . . . . . . . . . . . . . . |
$$ | . . 8 9 . . . . . . . . . . . . . . . |
$$ | . . 0 . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . O 2 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
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Joaz Banbeck
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Re: Opening problems for AI: Problem 48

Post by Joaz Banbeck »

Move 'a' forces white to connect two stones that otherwise had a slightly stretched connection, and in addition, now C11 is strong and opposes black's natural extension up the side.

Click Here To Show Diagram Code
[go]$$Bc Terrible for black, IMHO
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . O . . O . . . X . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 3 . . . . . . . . . . . . . . . |
$$ | . . 2 1 . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . X . . . . . . . . . . b c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So the best move is 'b' or 'c'. I gotta think on that a bit.
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Kirby
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Re: Opening problems for AI: Problem 48

Post by Kirby »

'b' seems good to me. Gospelish, and I like 'b' better than 'c'.
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Re: Opening problems for AI: Problem 48

Post by Gomoto »

b over c because of the ladder
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Knotwilg
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Re: Opening problems for AI: Problem 48

Post by Knotwilg »

I don't see how the gospel moves can be worst. I can see how A is bad, as it will build influence towards a solid formation. As for which move to play, B or C, I have a personal preference for B but it is not rationalized.
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Re: Opening problems for AI: Problem 48

Post by Gomoto »

White can play 1 (BOTL). The normal response of black 2 is not optimal. (BOTL) white can block at 3. Black would now like to attach at 4 and hope for white to extend at d. But white will not comply and just wedge into the dog's face at 5 (BOTL). After 9 black would like to cut at d but this is not possible Because Of The Ladder at P6 and black has to fall back to e. Black does not like this result and therefore has to play 2 at O2 in the first place. But now suddenly b instead of c looks hotter (BOTL) ;-)

Because of the ladder my personal preference c is a little bit smaller than b in this problem out of Bill's sleeves.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . O . . O . . . X . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 7 d . . |
$$ | . . . . . . . . . . . . . . 8 4 O e . |
$$ | . . X , . . . . . , . . . 1 9 5 6 . . |
$$ | . . . . X . . . . . . . . 3 2 . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
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Harleqin
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Re: Opening problems for AI: Problem 48

Post by Harleqin »

I think that 'a' is actually best. There are all kinds of answers, there are all kinds of possibilities to develop the upper left, and there are ladder implications to the lower right. Finally, it seems like White also should not tenuki to the lower right. In summary, I think it is a very useful probe, and now is the time to play it.
A good system naturally covers all corner cases without further effort.
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Re: Opening problems for AI: Problem 48

Post by dhu163 »

Speculatively:
Current position:
1. c as always stands out. b seems fine too but it doesn't seem to work with the lower left. a seems good shape locally, like proper joseki, but I can't see why it is urgent. can it not be played later? It seems heavy to commit to pulling out here Not sure though.

Opp to play
1. b

Past:
1. W seems to have played too many 3rd line side stones.

Check:
1. ?
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