Opening problems for AI: Problem 28

For lessons, as well as threads about specific moves, and anything else worth studying.
Post Reply
Bill Spight
Honinbo
Posts: 10905
Joined: Wed Apr 21, 2010 1:24 pm
Has thanked: 3651 times
Been thanked: 3373 times

Opening problems for AI: Problem 28

Post by Bill Spight »

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
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: Opening problems for AI: Problem 28

Post by Uberdude »

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.
Top
User avatar
Knotwilg
Oza
Posts: 2432
Joined: Fri Jan 14, 2011 6:53 am
Rank: KGS 2d OGS 1d Fox 4d
GD Posts: 0
KGS: Artevelde
OGS: Knotwilg
Online playing schedule: UTC 18:00 - 22:00
Location: Ghent, Belgium
Has thanked: 360 times
Been thanked: 1021 times
Contact:
Contact Knotwilg

Re: Opening problems for AI: Problem 28

Post by Knotwilg »

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.
Top
Bill Spight
Honinbo
Posts: 10905
Joined: Wed Apr 21, 2010 1:24 pm
Has thanked: 3651 times
Been thanked: 3373 times

Re: Opening problems for AI: Problem 28

Post by Bill Spight »

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
dhu163
Lives in gote
Posts: 474
Joined: Tue Jan 05, 2016 6:36 am
Rank: UK 2d Dec15
GD Posts: 0
KGS: mathmo 4d
IGS: mathmo 4d
Has thanked: 62 times
Been thanked: 278 times

Re: Opening problems for AI: Problem 28

Post by dhu163 »

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
Post Reply

Return to “Study Group”