It is currently Thu Mar 28, 2024 9:41 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 5 posts ] 
Author Message
Offline
 Post subject: Opening problems for AI: Problem 28
Post #1 Posted: Sat Jul 11, 2020 10:42 pm 
Honinbo

Posts: 10905
Liked others: 3651
Was liked: 3374
I like this one, too. :)

Black to play.

Black's textbook play loses 17½% to par, according to Elf. Assuming komi, as always.

Click Here To Show Diagram Code
[go]$$Bcm9 Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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

Visualize whirled peas.

Everything with love. Stay safe.

Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 28
Post #2 Posted: Sun Jul 12, 2020 12:30 am 
Judan

Posts: 6725
Location: Cambridge, UK
Liked others: 436
Was liked: 3719
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
I don't know what the textbooks say (q14 to prevent press and threaten invasion?), but confident to predict bots say black should correct his mistake of playing a 5-3 point by closing the corner, per gospel.


This post by Uberdude was liked by: Bill Spight
Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 28
Post #3 Posted: Sun Jul 12, 2020 3:16 am 
Oza
User avatar

Posts: 2408
Location: Ghent, Belgium
Liked others: 359
Was liked: 1019
Rank: KGS 2d OGS 1d Fox 4d
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Opening gospel says lower right enclosure, unless another place is more urgent.

Click Here To Show Diagram Code
[go]$$Bcm9 Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . 2 3 . . |
$$ | . . . . . . . . . . . . . . . 4 . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , 1 . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White's extension may make this play efficient for her.

Click Here To Show Diagram Code
[go]$$Bcm9 Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . O . . . . . . . . . . X . 2 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


How about this exchange? It looks more messy for both. Messy is usually a little better for White, who has komi in the pocket.

So I'll go with the enclosure.


This post by Knotwilg was liked by: Bill Spight
Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 28
Post #4 Posted: Mon Jul 13, 2020 8:27 am 
Honinbo

Posts: 10905
Liked others: 3651
Was liked: 3374
This position comes from GoGoD 1660+c, Honinbo Doetsu (W) vs. Honinbo Dosaku, but it could have come from a modern game.

Click Here To Show Diagram Code
[go]$$Bcm9 Ideal extension
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . f . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 , c . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . . . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . e . . . |
$$ | . . . , . . . . . , . . . . . , 2 . . |
$$ | . . . O . . . . . 3 . . . . B . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Dosaku played the ideal 5 space extension from the top left enclosure, leaving the 2 space extension at a towards the bottom left enclosure, or a one space jump at c if White extends to b. This is one of the first things we learn about development from a corner enclosure. It is surprising to learn that it could lose so much in such a simple position. Assuming komi, OC.

Doetsu approached the bottom right corner and then Dosaku played the extension at :b11: on the bottom side, which also prevents a pincer against :bc:. But that excellent play seems to be dubious, losing 5% by comparison with d, according to Elf. e and f are also playable. (It would not surprise me if Elf preferred e the next time it analyzed this position. The bots love the press. :))

Click Here To Show Diagram Code
[go]$$Bcm11 Mainline variation for :b11:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . 5 . . . |
$$ | . . O . . . . . . . . . . . . 3 4 . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . O 9 a . . 7 . 2 . 8 . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After :b11: :w12: pincers, OC. Then Black plays the press in the bottom right corner, followed by his own pincer at :b17:. :w18: makes a small base, continuing the attack. Then, instead of the two space extension at a, Black attaches against the corner enclosure on the 3d line.

Click Here To Show Diagram Code
[go]$$Bcm11 Variation II for :b11:, the press
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . O . . . . . . . . . . . . 1 2 . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]



Click Here To Show Diagram Code
[go]$$Bcm15 The press, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . 8 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . 6 . . . . . . . . . . X O . . |
$$ | . . . , 2 5 . . . 7 . . . . . , O . . |
$$ | . . . O 1 3 . . . . . . . . X . . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After the press in the bottom right, :b15: plays the 3d line attachment in the corner, and then Black stakes out the bottom side. Then :w22: plays his own press in the top right corner. The press is a real workhorse. :)

Top choice: Enclose the bottom right corner

Click Here To Show Diagram Code
[go]$$Bcm9 Two enclosures
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . . X , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , 1 . . |
$$ | . . . O . . . . . . . . . . B . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Making a second enclosure is also an ideal textbook play. But before the AI era Dosaku's extension would also have been considered playable. One problem with it is that :w10: at 9 is too good. The 5-3 stone, :bc:, cries out for an enclosure.

Click Here To Show Diagram Code
[go]$$Bcm9 Two enclosures, mainline
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . O . . . . O . . . . |
$$ | . 7 X , . . . . . , . . . . . , X . . |
$$ | . . 4 5 9 . . . . . . . . . . a . . . |
$$ | . . 6 8 . . . . . . . . . . . 2 . 3 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 0 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , 1 . . |
$$ | . . . O b . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w10: plays the taisha. OC, a is also playable. :b11: plays the slide. Then :w12: plays the 3d line attachment against the top left enclosure, and White stakes out the left side. :b19: plays the attachment at b.

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

Visualize whirled peas.

Everything with love. Stay safe.

Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 28
Post #5 Posted: Sat Jan 01, 2022 3:02 pm 
Lives in gote

Posts: 470
Liked others: 62
Was liked: 278
Rank: UK 2d Dec15
KGS: mathmo 4d
IGS: mathmo 4d
Speculatively:
Current position:
1. Of course B must play R4 or perhaps Q5.
2. Is Q15 a textbook move here? I think it is probably one of the best alternatives.

Opp to play
1. Of course W should play R3 or R4. I prefer R4 in this position since P3 already splits W's lower side development so R3 doesn't really help (it isn't as if the lower side is B's and R3 helps gain access/life with N3 and P2). R4 helps attack the upper right 3-4 stone too. If not, I would exchange Q15 first before diving with R3 (or perhaps still R4).

Past:
1. B has deviated with the lower right 5-3 and W at K17 is weird to compete for the relatively small upper side, especially without having gotten Q15. B has sente to play R4, so B is marginally ahead.

Check:
1. of course, but I somewhat expected B to have played on the lower side instead. They seemed to really like creating living groups on the 3rd line back there, slightly disrespecting the D11 and F16 centre reductions.

Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group