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 Post subject: Opening problems for AI: Problem 32
Post #1 Posted: Thu Jul 16, 2020 5:52 am 
Honinbo

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White to play.

Click Here To Show Diagram Code
[go]$$Wcm16 White to play
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White's textbook play loses 15% to par by Elf's reckoning. Assuming komi, OC.

Enjoy! :)

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Everything with love. Stay safe.


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 Post subject: Re: Opening problems for AI: Problem 32
Post #2 Posted: Thu Jul 16, 2020 12:36 pm 
Lives in gote

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Bill Spight wrote:
White to play.

Click Here To Show Diagram Code
[go]$$Wcm16 White to play
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . a . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]



I'll wager white played 'a', but the AI bible says take the open corner. I've noticed the star point a lot, so I'm going with 'b'.

As a matter of interest, has anyone noticed any rules of thumb for when the AI prefers a star point compared to a 3-4 point in these kinds of situations?


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 Post subject: Re: Opening problems for AI: Problem 32
Post #3 Posted: Thu Jul 16, 2020 11:27 pm 
Judan

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Continuing the upper left has relatively small value. Approaching the lower left corner should be slightly less valuable than occupying the empty corner but this is very hard to explain. The most interesting question is whether to press in the upper right in expected sente before taking the empty corner. Since Black can push once more to take away sente and so the empty corner, White should first take the empty corner himself. Afterwards, White has similarly attractive follow-ups in the lower left (approach) and upper right corners (press). Which move in the empty corner? Since White can press in the upper right, Black avoids a move in the lower right aiming at building a big moyo on the right side, i.e., avoids Q5, R5, P4 or O4. Hence, Q4, R3, Q3 or P3 (cooperates with E4) are possible but current AI would not play P3.


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 Post subject: Re: Opening problems for AI: Problem 32
Post #4 Posted: Fri Jul 17, 2020 4:04 am 
Oza
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We have 3 corners with respectively 0, 1 and 2 stones

Empty corner is the obvious choice.

However, AI exceptionally like pincers when they are also an extension of influence. White may forestall it with a 2 space extension. Pressing looks like black may cut instead of walking along.

The textbook play may have been the attachment or the kosumitsuke
I still go for the empty corner

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 Post subject: Re: Opening problems for AI: Problem 32
Post #5 Posted: Fri Jul 17, 2020 5:24 am 
Oza

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Bill:

In the same way that we look for Direct 3-3 and shoulder hits etc if we are told an AI bot played next, I think we can safely say that we now look for a Bill Spight press when we know who set the problem :)

But two points for you to consider before you reveal your answer:

1. Elf encountered the upper-left joseki in a game against a human (Ch'oe Ch'eol-han) and played elsewhere. Golaxy likewise. In other words, in games with 7.5 komi.

2. This sort of question came up in "9-dan Showdown" (Go Seigen vs Fujisawa K) in two games, and of course the surrounding situation is discussed at length there. Fujisawa in both cases chose not to continue the joseki but went for a big-point strategy instead. I seem to recall that he went for this partly on the basis of tedomari considerations, which may well apply here, too.

In fact, of all the games that show that upper-left joseki in human games, the human chose NOT to play the prime text-book more than half the time. This is perhaps a case of the joseki not being joseki :lol:


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 Post subject: Re: Opening problems for AI: Problem 32
Post #6 Posted: Fri Jul 17, 2020 8:23 am 
Honinbo

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John Fairbairn wrote:
Bill:

In the same way that we look for Direct 3-3 and shoulder hits etc if we are told an AI bot played next, I think we can safely say that we now look for a Bill Spight press when we know who set the problem :)


That may be the result of looking for sufficiently large mistakes. You may have a move that in itself, or in general, is not so bad, but when there is a press on the board, it is worse by comparison, and therefore I notice it.

John Fairbairn wrote:
But two points for you to consider before you reveal your answer:

1. Elf encountered the upper-left joseki in a game against a human (Ch'oe Ch'eol-han) and played elsewhere. Golaxy likewise. In other words, in games with 7.5 komi.


Further discussion hidden for courtesy. :)

OC, komi may well be a factor. But given the strength of both sides at that point in the joseki, I suspect that tenuki is usually right, komi or no.

John Fairbairn wrote:
2. This sort of question came up in "9-dan Showdown" (Go Seigen vs Fujisawa K) in two games, and of course the surrounding situation is discussed at length there. Fujisawa in both cases chose not to continue the joseki but went for a big-point strategy instead. I seem to recall that he went for this partly on the basis of tedomari considerations, which may well apply here, too.

In fact, of all the games that show that upper-left joseki in human games, the human chose NOT to play the prime text-book more than half the time. This is perhaps a case of the joseki not being joseki :lol:


In Waltheri tenuki is the most usual choice, a bit more than ⅓ of the time, with hane a close second at ⅓ of the time. In the AI era, tenuki may become more frequent. :)

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 Post subject: Re: Opening problems for AI: Problem 32
Post #7 Posted: Fri Jul 17, 2020 1:20 pm 
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 Post subject: Re: Opening problems for AI: Problem 32
Post #8 Posted: Sat Jul 18, 2020 1:59 am 
Judan

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RobertJasiek wrote:
The most interesting question is whether to press in the upper right in expected sente before taking the empty corner. Since Black can push once more to take away sente and so the empty corner, White should first take the empty corner himself.


When you want to get sente from the press, there's another idea I've learnt from bots (e.g. in Kobayashi-denied fuseki) which is quite often better than the extra push, shown below for comparison. Pushing means you help white build strength in the centre, and the turn of 7 is juicy.
Click Here To Show Diagram Code
[go]$$Wcm1 Push again for sente
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . 8 . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . S S 1 2 . . |
$$ | . . . . . . . . . . . . . S S 3 4 . . |
$$ | . . . . . . . . . . . . . S S 5 7 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The other idea is the somewhat crude and cramped looking kick / kosumi-tsuki in the corner. If white fighting-spiritly says "Hey, you ignored my press so I will cover!" with 3 that's often not the best choice: if white continues locally building the thickness with 7 then black takes sente for 8 in empty corner or wherever you wanted, and the key difference to above, to my understanding, is the white group here is less thick/strong as the first diagram. By not pushing from behind black avoids giving white the strength and potential eyespace adjacent to the wall; in both variations white has a wall of 2 stones without an extension facing down the right side. Also in this variation black can q16 empty triangle and cut (sometimes should try to get q16 in sente before tenuki, but white may resist).
Click Here To Show Diagram Code
[go]$$Wcm1 Kick
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . 6 4 . . . . |
$$ | . . O X O X . . . . . . 7 5 O 2 . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . 1 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . 8 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Of course white doesn't need to take gote at the top, but can take the empty corner, and then black can take the juicy hane at 8 (or lower left). If black doesn't take 8 but lower left at a then it's not sente/painful to allow white to spend a gote there: by playing the corner kick black lowers the temperature of this corner, allowing for grabbing the other big opening points.
Click Here To Show Diagram Code
[go]$$Wcm1 Kick
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . 6 4 . . . . |
$$ | . . O X O X . . . . . . 8 5 O 2 . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . 1 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a , X . . . . , . . . . . 7 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Compare to if white forcefully takes the empty corner in the push an extra time line, now black is pretty much obliged to take 6 here as reverse sente...
Click Here To Show Diagram Code
[go]$$Wcm1 Push again for sente, tenuki 1
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . 1 2 . . |
$$ | . . . . . . . . . . . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . 6 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . 5 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


... because if black takes the lower left, white extend 7 is sente now because there's no moves big enough remaining to be worthwhile taking and allowing the white turn.
Click Here To Show Diagram Code
[go]$$Wcm1 Push again for sente, tenuki 2
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . 1 2 . . |
$$ | . . . . . . . . . . . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 6 , X . . . . , . . . . . 5 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Rather than blocking, white can hane at 3, which is looking for black to obediently block inside and then white can get sente, having made p18 a less good follow up for black. Black counters with 4, and then 7 is the toughest move for white to keep maximum pressure on the corner (as now black r18 block doesn't threaten to capture a stone). After 9 black has 2 main choices:
- slide to a, white defends at b, and then black has sente for empty corner at c, or
- crawl and then jump with d-e-f, plus is black isn't so low, con is white got stronger in centre so can tenuki to empty corner, and black acvtivating the cutting stones or white defending there is a big move that'll come fairly soon, but probably after shimaris/approaches on lower side.
Click Here To Show Diagram Code
[go]$$Wcm1 New joseki
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . 7 9 3 . . . |
$$ | . . O X O X . . . . . . . 8 O 2 6 . . |
$$ | . . . , O X . . . , . . . b 4 5 X . . |
$$ | . . . O . . . . . . . . . . . 1 d . . |
$$ | . . . . . . . . . . . . . . . e . a . |
$$ | . . . . . . . . . . . . . . . . f . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . c . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


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 Post subject: Re: Opening problems for AI: Problem 32
Post #9 Posted: Sat Jul 18, 2020 5:29 am 
Honinbo

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This position comes from GoGoD 1782-08-10, Mizutani Takugen (W) vs. Yasui Senchi Senkaku. :w16:, while joseki, was a mistake, losing 15% to par, according to Elf. Assuming komi, as always. Per my disucssion above with John Fairbairn, it looks like :w16: may no longer be considered joseki.

Click Here To Show Diagram Code
[go]$$Bcm15 Game record
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O 1 . . . , . . . . . , X . . |
$$ | . . . O . 2 3 . . . . . . . . . . . . |
$$ | . . . . . 4 5 . . . . . . . . . . . . |
$$ | . . . . . 7 6 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b15:, while joseki, also appears to be a mistake. The cut, :b21:, leads to a big fight in the top left quadrant. Below is Elf's mainline variation for :b19:.

Click Here To Show Diagram Code
[go]$$Bcm19 Mainline variation for :b19:
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . O X . . . . . . . . a . . . |
$$ | . . . . . O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 3 5 . . . . . . . . . . . . . . . |
$$ | . . b 4 X 9 . . . , . . . . . 1 . . . |
$$ | . . 2 . 6 7 . . . . . . . . . . . . . |
$$ | . . . . . 8 0 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b19: occupies the last open corner. Then :w20: invades the bottom left corner. a and b are also playable.

Click Here To Show Diagram Code
[go]$$Bcm29 Mainline variation for :b19:, continued
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . 4 . . O 7 . . . |
$$ | . . . , O X . . . , . . . . 8 , X . . |
$$ | . . . O . O X . . . . . . . . a . . . |
$$ | . . . . . O 1 . . . . . . . . . 9 . . |
$$ | . . . . . 2 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . X X . . . . . . . . . . . . . . . |
$$ | . . . O X X . 6 . , . . . . . X . . . |
$$ | . . O . O X . b . . . . . . . . . . . |
$$ | . . . . . O O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b29: returns to the push in the center. :w30: extends. a is also playable. Then :b31: extends on the left side, which is now hot. :w32: makes a base in the top right. :b33: encloses the bottom right corner. :w34: prevents Black b or thereabouts. Then :b35: and :b37: secure the top right corner.

Elf's top choice for :w16: : Occupy the last empty corner.

Click Here To Show Diagram Code
[go]$$Wcm16 Last empty corner
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . 3 4 . . |
$$ | . . . . . . . . . . . . . . . 5 6 . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . c , X . . . . , . . . . . , 1 . . |
$$ | . . b . . . . . . . . . . . 2 a . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's top choice is :w16: in the bottom right corner, with a in second place. Gomoto indicates that Katago, which is stronger than Elf, prefers the press at 18, followed by b, the 3-3 invasion of the bottom left corner. Elf's top two choices are KataGo's 3d and 4th place choices. But the difference in evaluation is only 0.1 point, surely within KataGo's margin of error.

:b17: approaches the bottom right corner. Enclosing the bottom left corner at c is also playable. Then White plays the press in the top right corner.

Click Here To Show Diagram Code
[go]$$Bcm23 Mainline for :w16:, continued
$$ ---------------------------------------
$$ | . . . . . X . . . . . . . . . . . . . |
$$ | . . . O X . X . . . . . . . . . . . . |
$$ | . . O X O X . . . . . . . . O . . . . |
$$ | . . . , O X . . . , . . . . . , X . . |
$$ | . . . O . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . 4 . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . , X . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . X 2 . . . |
$$ | . . . . . . . . . . . . . . 3 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b23: plays the press in the bottom right corner. :w24: replies with the kick and slide.

The main takeaway, I think, is that the central hane for :w16: is not worth it, in this and probably most cases, and may possibly be considered joseki no longer. Certainly the press, the 3-3 invasion against the 5-4, and the last open corner are all better plays.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #10 Posted: Sat Jul 18, 2020 7:35 am 
Oza

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Quote:
The main takeaway, I think, is that the central hane for :w16: is not worth it, in this and probably most cases, and may possibly be considered joseki no longer.


Any reason for not mentioning the main joseki, E14? I mean main in the sense of most played, and also (?therefore) the only line given as joseki by Kitani. The hane is mentioned by Kitani but evaluated as "an even result", which is usually for lines not yet played enough to be considered joseki.

I just happen to be familiar with this pattern because of "9-dan Showdown".

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 Post subject: Re: Opening problems for AI: Problem 32
Post #11 Posted: Sat Jul 18, 2020 10:20 am 
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John Fairbairn wrote:
Quote:
The main takeaway, I think, is that the central hane for :w16: is not worth it, in this and probably most cases, and may possibly be considered joseki no longer.


Any reason for not mentioning the main joseki, E14? I mean main in the sense of most played, and also (?therefore) the only line given as joseki by Kitani. The hane is mentioned by Kitani but evaluated as "an even result", which is usually for lines not yet played enough to be considered joseki.

I just happen to be familiar with this pattern because of "9-dan Showdown".


The main reason for not mentioning E-14 is that I choose these problem positions by going over more than 20 games each, on average. I don't decide on the point of the problem ahead of time. If E-14 had shown up and was a large enough error, I would have mentioned it. Or if Elf had recommended it, or even given it more than 1500 rollouts, I would have mentioned it, then, too. :)

When I was around 2 kyu, I recall reading something about this joseki, maybe in a go magazine. Anyway, the author did not recommend the hane, I don't remember why, but he did say that the player with the corner (White in this case) did generally need protection from the atari at E-15, and that the hanging connection with E-14 offered that. His recommendation for Black was not to play that atari, because it was aji keshi, but to play the keima at E-15, since to prevent the atari White would have to make bad shape.

Anyway, in the Waltheri database tenuki is the most popular human option at around 36%, with the hane next at around 33%, and the hanging connection third at around 20%.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #12 Posted: Sat Jul 18, 2020 11:05 am 
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About the hanging connection

Here is the first case I found where the hanging connection was played instead of tenuki. :)

GoGoD 1786-04-10, Honinbo Retsugen (W) vs. Hattori Inshuku, my friend :)

A few comments, based upon Elf's calculations.

Click Here To Show Diagram Code
[go]$$Bc Moves 1 to 8
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . 3 , 4 . . |
$$ | . . 2 . . . . . . . . . . . . 7 5 6 . |
$$ | . . . . . . . . . . . . . . . . 8 a . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b1: Within the margin of error.
:w2: Minor error.
:b3: Minor error. Once is probably OK, twice is too much.
:w4: Within the margin of error. Occupy the last empty corner, is a good rule of thumb, though.
:b5: Ditto.
:w8: Within the margin of error. a may be better, however.

Click Here To Show Diagram Code
[go]$$Bcm9 Moves 9 to 15
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . , . . . . . , . . . . X , O 3 . |
$$ | . . O . . . . . . . . . . 7 . X X O . |
$$ | . . . . . . . . . . . . . . . 6 O 1 4 |
$$ | . . . . . . . . . . . . . . . . . 2 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w14: Minor error. Occupy the last open corner.
:b15: Blunder. Loses 21½% to par. Occupy the last open corner.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #13 Posted: Sat Jul 18, 2020 11:38 am 
Oza

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Quote:
Anyway, in the Waltheri database tenuki is the most popular human option at around 36%, with the hane next at around 33%, and the hanging connection third at around 20%.


GoGoD has 210 games, with the hane and the hanging connection at 60 each. Both are still being played, but the hane is ever so slightly the modern preference. Possibly it's seen as more severe in the modern 7.7 komi era?


This post by John Fairbairn was liked by: Bill Spight
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Post #14 Posted: Sat Jul 18, 2020 11:45 am 
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John Fairbairn wrote:
GoGoD has 210 games, with the hane and the hanging connection at 60 each. Both are still being played, but the hane is ever so slightly the modern preference. Possibly it's seen as more severe in the modern 7.7 komi era?

Emphasis mine.

Still being played? Early in the game?

If so, my guess is that that won't last. Early in the game tenuki looks to be too good.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #15 Posted: Sat Jul 18, 2020 12:01 pm 
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Here is another example in early play. The next one I found.

GoGoD 1823-12-18b, Hattori Inshuku (W) vs. Inoue Ansetsu. Castle game.

Click Here To Show Diagram Code
[go]$$Bc Moves 1 to 10
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . . . . . . . 3 . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 0 . . . . . . . . . . . . . . . . |
$$ | . 8 7 9 . . . . . . . . . . . . 2 . . |
$$ | . . 6 , 5 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b1: Within the margin of error.
:w2: Minor error.
:b3: Borderline error. Probably better to play in an open corner or invade the bottom right corner.
:b5: Minor error. Invade the bottom right corner.
:w6: Within the margin of error.
:b9: Good.

Click Here To Show Diagram Code
[go]$$Bcm11 Moves 11 to 17
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 2 . . . . . . . . . . . . . . . . . |
$$ | 4 1 O 6 . . . . . . . . . . . . . . . |
$$ | . O X X . 7 . . . . . . . . . . O . . |
$$ | . 3 O , X . . . . , . . . . . , . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w16: Minor error. Enclose the bottom right corner.
:b17: Blunder. Lose 19½% to par. Invade the bottom right corner.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #16 Posted: Sat Jul 18, 2020 12:10 pm 
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What about :w10: ;-)

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 Post subject: Re: Opening problems for AI: Problem 32
Post #17 Posted: Sat Jul 18, 2020 12:19 pm 
Honinbo

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Gomoto wrote:
What about :w10: ;-)

Within 1% of the 2d line extension. I figure the difference is very likely to be noise.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #18 Posted: Sat Jul 18, 2020 12:25 pm 
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This time I went looking for a modern example later in the game, but still no tenuki. Here it is.

GoGoD 1939-04-19, Inoue Ichiro, 4 dan (W) vs. Takagawa Kaku, 4 dan. Oteai.

Click Here To Show Diagram Code
[go]$$Wcm20 Still bad
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . X , . O . . . , . . . X O , . . . |
$$ | . . . . X . . . . . . . . X O X O . . |
$$ | . . . . . . . . . . . . X . X O . . . |
$$ | . . . . . . . . . . . . . X . . . . . |
$$ ---------------------------------------[/go]

:w20: Mistake. Loses 16% to par. Enclose the top left corner at a.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #19 Posted: Sat Jul 18, 2020 3:36 pm 
Oza

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Quote:
Still being played? Early in the game?


How early is early? Earliest decision point with this joseki seems to be move 15. Four contrasting examples in roughly last decade: twoopting for tenuki and two for hanging connection.

Hane: in recent times the earliest this was played was move 18 (2005). Cases since then have been rather late in the game (beyond move 60).

If you go back another ten years or so, early decision point combined with early hane or hanging connection seems to be the norm (moves 15 to 23).

I could imagine pro views on each choice haven't really changed, but we are seeing far fewer examples now simply because takamoku has fallen right out of fashion in the AI age: a sharp decline culminating in just 7 examples in 2019 and none so far in 2020.

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 Post subject: Re: Opening problems for AI: Problem 32
Post #20 Posted: Sat Jul 18, 2020 5:32 pm 
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John Fairbairn wrote:
Quote:
Still being played? Early in the game?


How early is early?


Early enough so that a normal option, such as playing in an empty corner, approaching a 3-4, 5-4, or 5-3, or making a shimari with one of them, or playing a press against a 3-4 is available. There may be positions where the hane or the hanging connection is preferable to one of those, but I would like to see such a position. :)

John Fairbairn wrote:
I could imagine pro views on each choice haven't really changed, but we are seeing far fewer examples now simply because takamoku has fallen right out of fashion in the AI age: a sharp decline culminating in just 7 examples in 2019 and none so far in 2020.


Good point. :) I think that there are positions where the 5-4 is playable, but not many where it is preferable to a 4-4 or 3-4.

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At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

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