It is currently Wed Feb 08, 2023 7:01 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 11 posts ] 
Author Message
Offline
 Post subject: What is the best yose move?
Post #1 Posted: Thu Jan 05, 2023 10:03 am 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
Click Here To Show Diagram Code
[go]$$B What is the best move ?
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X b O |
$$ . . . O O X a |
$$ . . . . O O X |
$$ . . . . . O . |
$$ . . . . . O O |
$$ . . . . . . . |[/go]

Very often apparently simple position are not that easy.
AGA rule : for a theoritical point of view what is the best move for black? a or b ?

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #2 Posted: Thu Jan 05, 2023 10:56 am 
Lives in gote

Posts: 368
Liked others: 29
Was liked: 171
GD Posts: 1072
I forget if the AGA rules allow for suicide, but 'a' should be superior to 'b' in any ruleset that does. For black to play 'b' leaves 'a' as a ko threat.

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #3 Posted: Thu Jan 05, 2023 11:02 am 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
pwaldron wrote:
I forget if the AGA rules allow for suicide, but 'a' should be superior to 'b' in any ruleset that does. For black to play 'b' leaves 'a' as a ko threat.

For me AGA rules do not allow suicide. BTW, if you prefer you can also consider you use chinese rules (I mean area counting).
I do not understand your point with ko threat : after black "a" white has also a ko threat availbale hasn't she?

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #4 Posted: Thu Jan 05, 2023 11:06 am 
Gosei
User avatar

Posts: 1627
Liked others: 151
Was liked: 452
If both players play alternatively then a and b are equivalent:

Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X 1 O |
$$ . . . O O X 3 |
$$ . . . . O O X |
$$ . . . . . O 2 |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X 3 O |
$$ . . . O O X 1 |
$$ . . . . O O X |
$$ . . . . . O 2 |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


But suppose Black plays a. Later if there is a ko fight, White ataris to make a ko threat, Black doesn't respond and White kills.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X 4 O |
$$ . . . O O . . |
$$ . . . . O O . |
$$ . . . . . O 2 |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


If another ko appears later then Black still has chances to survive by playing twice in a row. Then Black lives with 2 points and there is one dame left.

Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X . . |
$$ . . . O O 7 5 |
$$ . . . . O O . |
$$ . . . . . O O |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


On the other hand if Black plays b, after one ignored ko threat by Black and one ignored ko threat by White, Black lives with 3 points.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X 1 O |
$$ . . . O O X 4 |
$$ . . . . O O X |
$$ . . . . . O 2 |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X X . |
$$ . . . O O X 7 |
$$ . . . . O O 5 |
$$ . . . . . O O |
$$ . . . . . O O |
$$ . . . . . . . |[/go]


The end result depends on the parity of the number of dame at the end of the game, but with the assumption that the sequence of plays is Black-White-White-Black-Black, then b is superior by 1 point on average.

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #5 Posted: Thu Jan 05, 2023 11:23 am 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
Click Here To Show Diagram Code
[go]$$B What is the best move ?
$$ ---------------------------------------
$$ . . . O O X . |
$$ . . . O X X X |
$$ . . . O X b O |
$$ . . . O O X a |
$$ . . . . O O X |
$$ . . . . . O . |
$$ . . . . . O O |
$$ . . . . . . . |[/go]
Very nice jlt I agree entirely.
Here is an example where it remains only three small areas for the yose.
Black "b" is the best move in order to avoid the following (wrong) sequence :

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #6 Posted: Thu Jan 05, 2023 11:24 am 
Lives in gote

Posts: 368
Liked others: 29
Was liked: 171
GD Posts: 1072
Gérard TAILLE wrote:
For me AGA rules do not allow suicide. BTW, if you prefer you can also consider you use chinese rules (I mean area counting).
I do not understand your point with ko threat : after black "a" white has also a ko threat availbale hasn't she?


You're right. I was just thinking of the suicidal ko threat, but the external atari is there with the other move. My mistake.

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #7 Posted: Sat Jan 07, 2023 2:12 pm 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
Here is another problem:
Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . . . |
$$ . . . . O . O . . |
$$ . . . . O O . . . |
$$ . . . . . O O O . |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


What is the best choice :
Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . 3 . |
$$ . . . . O . O . . |
$$ . . . . O O . . 2 |
$$ . . . . . O O O 1 |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

or immediatly
Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . 1 . |
$$ . . . . O . O . . |
$$ . . . . O O . . . |
$$ . . . . . O O O . |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #8 Posted: Sat Jan 07, 2023 6:05 pm 
Lives in gote

Posts: 483
Location: Adelaide, South Australia
Liked others: 182
Was liked: 241
Rank: Australian 2 dan
GD Posts: 200
I guess it's the same philosophy as the first example: if white is going to respond to the peep, then the outcome is the same regardless of move order, so the real question is what happens if white ignores the peep?

If white responds: you're going to end up with this position in either case --

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


and the point is to stop white gaining a tempo with :wc: this way --

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


If white is going to ignore, then the :b1: - :w2: exchange below looks like an example of a reverse in CGT terms: black doesn't gain anything, and possibly loses something (one point from :b1: becoming a prisoner)?

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . 3 . |
$$ . . . . O . O . . |
$$ . . . . O O . . 2 |
$$ . . . . . O O O 1 |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


So I'd say just play :b1: at :b3: directly, an example of the 123 principle.

What have I missed?

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #9 Posted: Sun Jan 08, 2023 3:28 am 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
xela wrote:
I guess it's the same philosophy as the first example: if white is going to respond to the peep, then the outcome is the same regardless of move order, so the real question is what happens if white ignores the peep?

If white responds: you're going to end up with this position in either case --

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


and the point is to stop white gaining a tempo with :wc: this way --

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


If white is going to ignore, then the :b1: - :w2: exchange below looks like an example of a reverse in CGT terms: black doesn't gain anything, and possibly loses something (one point from :b1: becoming a prisoner)?

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . 3 . |
$$ . . . . O . O . . |
$$ . . . . O O . . 2 |
$$ . . . . . O O O 1 |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


So I'd say just play :b1: at :b3: directly, an example of the 123 principle.

What have I missed?


I understand your point. If white doesn't answer the peep then peeping immediately is better and I agree with you.
However what happens if you suppose all remaining yose points of the board are quite small ? In other word suppose black timing is good and white has to answer the peep in the two considered sequences ? Witch one is the best?

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #10 Posted: Tue Jan 10, 2023 2:15 pm 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
Here is a hint:
Click Here To Show Diagram Code
[go]$$B
$$ -----------------------------------------
$$ | . X . O . . . . . . . . . X . . . . . |
$$ | X X X O . . . . . . . . . X X X O . . |
$$ | . . X O . . . . . . . . . . X O . b . |
$$ | X X O O . . . . . . . . . . O . O . . |
$$ | O O O . . . . . . . . . . . O O . . . |
$$ | . . . . . . . . . . . . . . . O O O a |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . X X |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

AGA rules. By just adding a ko threat and a dame in the upper right corner do you see which of the two moves "a" and "b" is the best?

Top
 Profile  
 
Offline
 Post subject: Re: What is the best yose move?
Post #11 Posted: Mon Jan 16, 2023 5:44 am 
Lives in sente

Posts: 978
Liked others: 17
Was liked: 49
Rank: 1er dan
xela wrote:
Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ . . . X . . . . . |
$$ . . . X X X O . . |
$$ . . . . X O . 3 . |
$$ . . . . O . O . . |
$$ . . . . O O . . 2 |
$$ . . . . . O O O 1 |
$$ . . . . . . . X . |
$$ . . . . . . . X . |
$$ . . . . . . . X X |
$$ . . . . . . . . . |
$$ . . . . . . . . . |[/go]


So I'd say just play :b1: at :b3: directly, an example of the 123 principle.


I agree entirely with you xela, the exchange :b1: :w2: followed by the peep at :b3: is generally inferior to the immediat peep. I like very much the 123 principle and its application is good sense.
A proof of the 123 principle efficiency is that is is quite difficult to change a little the position in order to make the :b1: :w2: better.
Maybe here is an exemple after a lot of tries:
Click Here To Show Diagram Code
[go]$$B
$$ -----------------------------------------
$$ | . X O O . . . . . . . . . X . . . 3 . |
$$ | X X X O . . . . . . . . . X X X O O . |
$$ | . . X O . . . . . . . . . . X O X X . |
$$ | X X O O . . . . . . . . . . O O O . . |
$$ | O O O . . . . . . . . . . . O O . . 2 |
$$ | . . . . . . . . . . . . . . . O O O 1 |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . . X X |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

If I am not wrong, due to the white ko threat existing in the top right corner, the exchnage :b1: :w2: followed by the standart :b3: move is better than the immediat :b3: move.
Here again it is only an exception. The 123 principle is a very good principle isn't it?

Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 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