Quite strange result in area counting rules

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Cassandra
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Re: Quite strange result in area counting rules

Post by Cassandra »

RobertJasiek wrote:Until successive passes, the game is global because decisions must always take into account the whole board...
This is a question of strategy, not of the rules.

Nevertheless, wouldn't it be preferable to have as less "global" restrictions by the rules as possible for a "global" game? :razz:
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)
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Re: Quite strange result in area counting rules

Post by RobertJasiek »

Thanks for the NSK anomaly! The defensive British ko rules design avoids it nicely.

I invented NSK with the wording "A player may not use a board play to recreate a position if he has used one to create it". I did overlook your anomaly. NSK was meant to improve on the rules concept of SSK. I still think the concept of SSK is dubious. Concerning NSK, mea culpa. Every ko ruleset should at least imply the prohibition of 2-play-repetition without intervening pass(es).

Anyway, I have always thought that PSK is the best.
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Gérard TAILLE
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

BTW I found a second type of position, but more complex:
Click Here To Show Diagram Code
[go]$$W White to play
$$ ---------------------
$$ | . O . X O . O . . |
$$ | X . X X O O O O O |
$$ | X X X O O X X X X |
$$ | O O O O X X O O O |
$$ | X X X X . X O O O |
$$ | O O O X X X O . . |
$$ | . . O X . X O X X |
$$ | X X O O X X O X O |
$$ | X . X O O X O O . |
$$ ---------------------[/go]
The best sequence seems the following :
Click Here To Show Diagram Code
[go]$$W White to play
$$ ---------------------
$$ | 3 O 6 X O . O . . |
$$ | X 1 X X O O O O O |
$$ | X X X O O X X X X |
$$ | O O O O X X O O O |
$$ | X X X X . X O O O |
$$ | O O O X X X O . . |
$$ | 4 . O X . X O X X |
$$ | X X O O X X O X O |
$$ | X 5 X O O X O O . |
$$ ---------------------[/go]
:b2: pass
Click Here To Show Diagram Code
[go]$$Wm7
$$ ---------------------
$$ | . 2 X X O . O . . |
$$ | X . X X O O O O O |
$$ | X X X O O X X X X |
$$ | O O O O X X O O O |
$$ | X X X X . X O O O |
$$ | O O O X X X O . . |
$$ | X 1 O X . X O X X |
$$ | X X O O X X O X O |
$$ | X O . O O X O O 4 |
$$ ---------------------[/go]
:w9: pass
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Re: Quite strange result in area counting rules

Post by RobertJasiek »

Cassandra wrote:This is a question of strategy, not of the rules.
Before even considering strategy, it is a matter of concept of how the game shall be.
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Re: Quite strange result in area counting rules

Post by luigi »

RobertJasiek wrote:I did overlook your anomaly. NSK was meant to improve on the rules concept of SSK. I still think the concept of SSK is dubious. Concerning NSK, mea culpa. Every ko ruleset should at least imply the prohibition of 2-play-repetition without intervening pass(es).
https://www.lifein19x19.com/forum/viewt ... 45&t=11510
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Gérard TAILLE
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

Another example of anomalie with NSSK:
Click Here To Show Diagram Code
[go]$$W White to play
$$ ---------------------------------------
$$ | . O X X . X O . . . . . . . . . . . . |
$$ | O . O X X X O . . . . . . . . . . . . |
$$ | . O X X O O O . . . . . . . . X . . . |
$$ | O O O X X X O . . , . . . . . , . . . |
$$ | O X X X O O O . . . . . . . . . . . . |
$$ | . O O . X X . . . . . . . . . . . . . |
$$ | . O X X X . . . . . . . . . . . . . . |
$$ | O . X . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . X . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Click Here To Show Diagram Code
[go]$$W White to play
$$ ---------------------------------------
$$ | . O X X . X O . . . . . . . . . . . . |
$$ | O 2 O X X X O . . . . . . . . . . . . |
$$ | . O X X O O O . . . . . . . . X . . . |
$$ | O O O X X X O . . , . . . . . , . . . |
$$ | O X X X O O O . . . . . . . . . . . . |
$$ | . O O 1 X X . . . . . . . . . . . . . |
$$ | . O X X X . . . . . . . . . . . . . . |
$$ | O . X . . . . . . . . . . . . . . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . X . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
After the exchange :w1: :b2: in the diagram above, comes the most stupid move you can imagine : white pass !!
Now if black takes the second ko by playing A19 then white is able to retake the ko immediatly.
Because black loses if she passes also, black has no solution.

Isn't it an anomalie?
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Gérard TAILLE
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

A little change to have a position more fun:
Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------------------
$$ | . O X X . X O . . . . . . . . . . . . |
$$ | O . O X X X O . . . . . . . . . . . . |
$$ | O O X X O O O . . . . . . . . X . . . |
$$ | . O O X X X O . . , . . . . . , . . . |
$$ | O 1 X X O O O . . . . . . . . . . . . |
$$ | . O O . X X . . . . . . . . . . . . . |
$$ | O O X X X . . . . . . . . . . . . . . |
$$ | . O X . . . . . . . . . . . . . . . . |
$$ | O X . X . . . . . . . . . . . . . . . |
$$ | . X . , . . . . . , . . . . . , . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
:b1: ?? is a terrible mistake isn't it?
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Re: Quite strange result in area counting rules

Post by luigi »

Am I missing something? Or do these examples really make no sense?
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Re: Quite strange result in area counting rules

Post by Pio2001 »

Gérard TAILLE wrote:Another example of anomalie with NSSK:
The problem with these examples is that the player who wants take advantage of NSK must pass forever in order to be able to retake the ko, thus give away the rest of the board to his opponent.
Therefore no one can gain anything with NSK when there is something else left on the board.

That's why in the example that I gave, Black's groups are so heavy. If there was an eyespace containing more than 3 intersections in Black's territory, White could win by stealing it while Black passes.
As soon as Black plays a stone on the board other than retaking the ko, the superko behaviour is back to normal.
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Gérard TAILLE
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

Pio2001 wrote:
Gérard TAILLE wrote:Another example of anomalie with NSSK:
The problem with these examples is that the player who wants take advantage of NSK must pass forever in order to be able to retake the ko, thus give away the rest of the board to his opponent.
Therefore no one can gain anything with NSK when there is something else left on the board.

That's why in the example that I gave, Black's groups are so heavy. If there was an eyespace containing more than 3 intersections in Black's territory, White could win by stealing it while Black passes.
As soon as Black plays a stone on the board other than retaking the ko, the superko behaviour is back to normal.
What do you mean Pio2001?
Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------------------
$$ | 5 O X X . X O . . . . . . . . . . . . |
$$ | O 3 O X X X O . . . . . . . . . . . . |
$$ | O O X X O O O . . . . . . . . X . . . |
$$ | . O O X X X O . . , . . . . . , . . . |
$$ | O 1 X X O O O . . . . . . . . . . . . |
$$ | . O O 2 X X . . . . . . . . . . . . . |
$$ | O O X X X . . . . . . . . . . . . . . |
$$ | . O X . . . . . . . . . . . . . . . . |
$$ | O X . X . . . . . . . . . . . . . . . |
$$ | . X . , . . . . . , . . . . . , . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
:w4: pass
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | X 6 X X . X O . . . . . . . . . . . . |
$$ | O X . X X X O . . . . . . . . . . . . |
$$ | O O X X O O O . . . . . . . . X . . . |
$$ | . O O X X X O . . , . . . . . , . . . |
$$ | O X X X O O O . . . . . . . . . . . . |
$$ | . O O O X X . . . . . . . . . . . . . |
$$ | O O X X X . . . . . . . . . . . . . . |
$$ | . O X . . . . . . . . . . . . . . . . |
$$ | O X . X . . . . . . . . . . . . . . . |
$$ | . X . , . . . . . , . . . . . , . . . |
$$ | . X . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
and black stones will be captured won't they?
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Re: Quite strange result in area counting rules

Post by Pio2001 »

I understand now: if Black plays elsewhere, White can take back the first ko.
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Gérard TAILLE
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

Pio2001 wrote:I understand now: if Black plays elsewhere, White can take back the first ko.
Yes that is the point. And if black passes after :w6: then white passes also and wins the game.
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Re: Quite strange result in area counting rules

Post by Gérard TAILLE »

luigi wrote:Am I missing something? Or do these examples really make no sense?
Luigi, is it clearer with the sequence I showed in viewtopic.php?p=266277#p266277 ?
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Re: Quite strange result in area counting rules

Post by luigi »

I get it now, thanks. This should bury NSSK for good. :)
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