It is currently Thu Mar 28, 2024 7:20 pm

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 29
Post #1 Posted: Mon Jul 13, 2020 8:48 am 
Honinbo

Posts: 10905
Liked others: 3651
Was liked: 3374
Click Here To Show Diagram Code
[go]$$Bcm21 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . O . . . . |
$$ | . . . , X . . . . , . . . . . , O O . |
$$ | . . O . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black to play.

Black's textbook play loses 13% to par, according to Elf. Assuming komi, as always.

Enjoy! :)

_________________
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 29
Post #2 Posted: Mon Jul 13, 2020 1:28 pm 
Judan
User avatar

Posts: 5539
Location: Banbeck Vale
Liked others: 1103
Was liked: 1456
Rank: 1D AGA
GD Posts: 1512
Kaya handle: Test
I've never liked the textbook attachment at the 3-3 point. If I tried to hold it, I ended up with cramped positions that wanted to extend along the side, but found that side to be already occupied by white (R9 in this case).
Invading at the 3-3 and then allowing it to be captured - which is a less common textbook move - just seemed to make life too easy for white.

So I have often played this:

Click Here To Show Diagram Code
[go]$$Bcm21
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . O . . . . |
$$ | . . . , X . . . . , . . . . . , O O . |
$$ | . . O . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . B O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207


This post by Joaz Banbeck was liked by: Bill Spight
Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 29
Post #3 Posted: Mon Jul 13, 2020 6:59 pm 
Lives in gote

Posts: 392
Liked others: 29
Was liked: 176
GD Posts: 1072
Bill Spight wrote:
Click Here To Show Diagram Code
[go]$$Bcm21 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . O . . . . |
$$ | . . . , X . . . . , . . . b . , O O . |
$$ | . . O . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . c . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . a . . . , . . . |
$$ | . . . . . . . . . . . . O . . O d . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I think both 'a', 'b' or 'c' look good. They reinforce their respective groups and consequently weaken the three white stones. I'd prefer 'a' because the two stone group looks weaker, and are more surrounded. This may be an illusion, though, where the two stones are currently light but adding a stone makes them heavy.

When presented with this position in real life, however, I'm likely just to chicken out and play 'd'. :)




This post by pwaldron was liked by 2 people: Bill Spight, Joaz Banbeck
Top
 Profile  
 
Offline
 Post subject: Re: Opening problems for AI: Problem 29
Post #4 Posted: Tue Jul 14, 2020 9:06 am 
Honinbo

Posts: 10905
Liked others: 3651
Was liked: 3374
The game is GoGoD 1925-01-00a, Honinbo Shusai Meijin (W) vs. Nakagawa Kamesaburo II, 8 dan.

Click Here To Show Diagram Code
[go]$$Bcm21 Actual game
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . O . . . . |
$$ | . . . , X . . . 2 , . . . . . , O O . |
$$ | . . O . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Nakamura played the checking extension, :b21:, and Shusai replied with :w22:. Both plays may be best with no komi, but Elf, assuming komi, reckons that :b21: loses 13% to par and :w22: loses 10½% to defending at a.

Click Here To Show Diagram Code
[go]$$Wcm22 Mainline for :w22:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . 9 5 3 O . . . . |
$$ | . . . , X . . . . , 6 7 4 2 . , O O . |
$$ | . . O . . . . . . . . 8 . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . a . . . , . . . |
$$ | . . . . . . . . . . . . O . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After :w22:, for :b23: Black plays the press on the top side to bolster his group in the top right quadrant. a and b are also playable, to bolster his group in the bottom right. b makes a base for either Black or White.

Click Here To Show Diagram Code
[go]$$Bcm21 Press, then invade
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . a . . . . . . . |
$$ | . . . X . . . . . . . . 4 2 O . . . . |
$$ | . . . , X . . . . , . . 3 1 . , O O . |
$$ | . . O . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black presses in the top right and then invades on the left side without further preparation. :w24: could also be at a. Since the Black invasion complicates the game, you can see how it might be unattractive with no komi.

Click Here To Show Diagram Code
[go]$$Wcm26 Invasion variation, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . O O O . . . . |
$$ | . . . , X b . . . , . . X X . , O O . |
$$ | . . O . 1 2 . . . . . . . . . X X . . |
$$ | . . . . 3 7 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . B . . . . . . . . . . . . . . . . |
$$ | . . . 4 6 . . . . . . . . . X . X . . |
$$ | . . O 5 8 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . O . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a . . . . . . . . . . X . . X . . |
$$ | . . X , X . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . O . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The jump attachment, :w26:, runs out with a leaning attack against :bc:. White could also play the 3d line attachment at a to make a base for White in the bottom left. :w30: blocks Black, but could also be at a or b. After :w32: pushes into the center, :b33: plays the strong central turn.

The key difference between the two mainline variations is the invasion on the left side. Black gets in the press in the top right in either case. Black needs no further preparation for the invasion. The kosumi in the top left corner is preparation enough. (OC, we know that an invasion is possible without the kosumi, as well. ;)) In komi go the checking extension amounts to a losing sente.

_________________
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 29
Post #5 Posted: Sat Jan 01, 2022 3:14 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. Ooh, this is much trickier with all the weak groups. Neither shape has particularly weak shape though so perhaps more plays aren't too big a deal. B is a bit undercut at S15.
2. Of course the upper side stands out: the last open side, E16 is vulnerable to W H17; B K17 can help support the P11 group.
3. I wouldn't invade C12 when W C10 has so much space, can counterattack E16, and is ahead in the centre with N9.
4. C8 is very attractive but I feel slightly early as miai with J3
5. J3 is nice but conflicts slightly with moves like M4 as O5 seems too weak to me.
6. O3/R3 still look good to me. O3 seems to perhaps give up too much access when there is so much space with W G3.
7. R7 is big fighting eyespace point, though perhaps slightly inefficient.

Opp to play
1. I feel H17 is biggest to shore up the left side at the same time as building something at the top.
2. G3 looks nice, but I'm not completely sure W has enough advantage in the fight if B plays M4.

Past:
1. I feel I have to slightly prefer B in this position as I think N9 looks slow and C10 is not at a vital point. However, handling O5 requires some careful use of W's weak points.

Overall:
1. Difficult, but I'm tending towards liking M4 since I'd like to threaten the N9 group in the fight. However, I'm not sure B can really win the fight though when W plays N5 and cuts.
2. Otherwise, I want to see K17 or L17.

Check:
1. Got most of my ideas right, but missed the sharpest fight that ELF was angling for.

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