RE: [computer-go] Ending games by two passes
Please correct me if I'm wrong, but are you saying that white is alive with TT-rules (=Tromp-Taylor?) or other rulesets with positional superko if black has not enough eyes left to fill as ko threats? If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Dave Van: [EMAIL PROTECTED] namens Erik van der Werf Verzonden: vr 24-10-2008 11:32 Aan: computer-go Onderwerp: Re: [computer-go] Ending games by two passes Hi Dave, This is a well-known problem with overly simplified rulesets. TT-advocates don't care about the rare anomalies. Did you notice that under positional superko you cannot take back the ko after *any* number of consecutive passes? This is yet another reason why in some cases filling an eye or playing in sure territory may be the best move... In your engine you don't want to use 3 passes unless absolutely necessary because of horizon effects. In my experience it is best to use 3 passes only if there is exactly one basic ko, and in all other cases use 2 passes to end the game. Erik On Fri, Oct 24, 2008 at 10:00 AM, [EMAIL PROTECTED] wrote: Is it correct to end games by 2 consecutive passes? When I learned go 20 years ago I was taught that 3 consecutive passes are required to end a game of go. In practice 2 passes are sufficient in nearly all cases, but sometimes 2 passes is not enough. Suppose we have this position in a 5x5 game with area scoring and 2.5 komi: (0 = white, # = black) ABCDE 5 00### 4 00#+# 3 +0### 2 00##+ 1 0#+## Black has just played C4. The controller is very simple. It only prohibits simple ko (superko is not checked) and all stones left on the board when the game ends are considered alive. White now at C1. Black has no choice but pass and then white quickly passes too. What happens now? If 2 passes end the game, the controller will award a win to white by the komi. If 3 passes are required to end the game, black captures at B1, white has no choice but pass, then black captures at A3 and will (probably) win the game. On could argue that controllers are smarter than the controller in my example, so 2 passes are usually sufficient in pactice, because the controller will query the engines for dead stones. But in my example, wouldn't both engines be justified to declare the white stones alive because of the 2 pass rule? Also, if I am correct, (light) playouts are usually controlled by an internal controller that is very similar to the controller in my example. Wouldn't they be vulnerable to this type of situation? Why not avoid this issue simply by requiring 3 consecutive passes to end the game? Am I missing something here? Dave ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
Hi Dave, This is a well-known problem with overly simplified rulesets. TT-advocates don't care about the rare anomalies. Did you notice that under positional superko you cannot take back the ko after *any* number of consecutive passes? This is yet another reason why in some cases filling an eye or playing in sure territory may be the best move... In your engine you don't want to use 3 passes unless absolutely necessary because of horizon effects. In my experience it is best to use 3 passes only if there is exactly one basic ko, and in all other cases use 2 passes to end the game. Erik On Fri, Oct 24, 2008 at 10:00 AM, [EMAIL PROTECTED] wrote: Is it correct to end games by 2 consecutive passes? When I learned go 20 years ago I was taught that 3 consecutive passes are required to end a game of go. In practice 2 passes are sufficient in nearly all cases, but sometimes 2 passes is not enough. Suppose we have this position in a 5x5 game with area scoring and 2.5 komi: (0 = white, # = black) ABCDE 5 00### 4 00#+# 3 +0### 2 00##+ 1 0#+## Black has just played C4. The controller is very simple. It only prohibits simple ko (superko is not checked) and all stones left on the board when the game ends are considered alive. White now at C1. Black has no choice but pass and then white quickly passes too. What happens now? If 2 passes end the game, the controller will award a win to white by the komi. If 3 passes are required to end the game, black captures at B1, white has no choice but pass, then black captures at A3 and will (probably) win the game. On could argue that controllers are smarter than the controller in my example, so 2 passes are usually sufficient in pactice, because the controller will query the engines for dead stones. But in my example, wouldn't both engines be justified to declare the white stones alive because of the 2 pass rule? Also, if I am correct, (light) playouts are usually controlled by an internal controller that is very similar to the controller in my example. Wouldn't they be vulnerable to this type of situation? Why not avoid this issue simply by requiring 3 consecutive passes to end the game? Am I missing something here? Dave ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
RE: [computer-go] Ending games by two passes
I'm glad we agree on this :) Your previous respons suggests that this issue has been debated before on this list, so I'll probably be able to find references about this issue. I wouldn't want to restart a debate here about positional superko :) Thanks, Dave Van: [EMAIL PROTECTED] namens Erik van der Werf Verzonden: vr 24-10-2008 12:18 Aan: computer-go Onderwerp: Re: [computer-go] Ending games by two passes On Fri, Oct 24, 2008 at 11:47 AM, [EMAIL PROTECTED] wrote: Please correct me if I'm wrong, but are you saying that white is alive with TT-rules (=Tromp-Taylor?) or other rulesets with positional superko if black has not enough eyes left to fill as ko threats? Yes. If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Does it really matter if it is human vs. human games? Why have different (inferior?) standards for computers anyway? Erik ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
[EMAIL PROTECTED] wrote: Is it correct to end games by 2 consecutive passes? It is correct to end games according to the used rules. Different rules use different numbers of passes, meanings of passes, or procedures assiated with passes. Some examples of numers of passes in actually used rulesets are: 2 passes 3 passes 2 passes + optionally once 2 passes 2 passes + optionally an arbitrary occurrence of yet 2 more passes 2 passes + 2 mandatory further passes after the first, 2 passes etc. One cannot say in general which better because this depends on one's aims. E.g., if the aim is shortest procedure on the rules level, then one would choose 2 passes. E.g., if the aim is to always allow each player a pass as a ko threat while a pass does relieve ko bans sufficiently, then one might choose 3 passes. E.g., if the first pass generates a conditional compensation and one wants to allow each player the filling of 1-sided dame regardless, then one might choose after the first, 2 passes. Etc. white is alive [under] rulesets with positional superko if black has not enough eyes left to fill as ko threats? If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Why would you be disgusted? The so called 1-eye-flaw occurs in much less than 1 of 10,000,000 games on the 19x19 board. In the entire history of go, it is reported to have occurred exactly once on the 9x9 board. Why do you dislike rules that enable something possible in theory but never occurring in practice? What do you have against 1-eye-flaw staying on the board at the game end? a) That it is a group with only 1 eye, b) that it is a group with only 1 ko, or c) that there is a string with only 1 liberty? Discussion of (a), (b), and (c): All rulesets used by humans allow games to end with groups with only 1 liberty. Example: # O # . # O . O # O # O # . # O . O # O # O # . # O . O # O # O # . # O . O # O . O # . # O . O # . This example shows two stable anti-sekis. By symmetry, it would be superfluous to prolong the game to dissolve either. If you are disgusted by 1-eye-flaw, then you should be even more disgusted by anti-sekis. I.e., you are disgusted by all rulesets currently used by humans. Strings with 1 liberty at the game end can also occur in hane-sekis, double ko sekis, quadruple kos, etc. Maybe you would human rules to be changed by ca so called greedy rule like A player may not pass if there is at least one string with exactly 1 liberty on the board. Such would dissolve all those disgusting things. One can even be more brutal in rules design like dissolving all those disgusting ordinary sekis, too. :) If you want to criticise positional superko, then state your first order aims! Which are they? I hate 1-eye-flaw!? Why should one particular shape be that all-important while we do not know some 100^500 other shapes yet? List them all, and then tell us what makes 1-eye-flaw so special :) More importantly, why are you worried about a shape at all? Shapes are the consequences of move-sequences and strategic decisions, see http://home.snafu.de/jasiek/j2003.html for a basis with that I defined eye formally. Write down your disgusting rules with such a design to enable yourself to define particular shapes in the first place so that you won't overlook any of your potentially hated disgusting shapes... BTW, positional superko IS accepted in some human rulesets like Chinese, Simplified Ing, or World Mind Sports Games 2008. -- robert jasiek ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
RE: [computer-go] Ending games by two passes
In my opinion the goal of a ko rule is to prevent games from not ending. 1: If one player can force a game to an end even when the other player aims at not ending the game, then the rule is good enough. In my previous example I would consider it an undesired side effect of a ko rule that white would win he game. There would be no danger of the game not ending if the ko rule were less restrictive than positional superko. Black should be allowed to capture white. 2: In rare cases the only non-losing way for either player could be to aim for an everlasting game, like a triple ko. In that case an everlasting game it near optimal play for both players. 3: I guess a ko rule does not have to be so restrictive to prevent everlasting games in in general. If it can solve situation 2 while still allowing 1, than that is good enough. Is it mathematically impossible to construct a ko rule that allows 1 and avoid 2? If not, I would prefer keep 1 and leave 2 undefined. I am no rules expert, but I cannot explain more clearly why I would be disgusted by positional superko. It is overly restrictive. Dave Van: [EMAIL PROTECTED] namens Robert Jasiek Verzonden: vr 24-10-2008 14:10 Aan: computer-go Onderwerp: Re: [computer-go] Ending games by two passes [EMAIL PROTECTED] wrote: Is it correct to end games by 2 consecutive passes? It is correct to end games according to the used rules. Different rules use different numbers of passes, meanings of passes, or procedures assiated with passes. Some examples of numers of passes in actually used rulesets are: 2 passes 3 passes 2 passes + optionally once 2 passes 2 passes + optionally an arbitrary occurrence of yet 2 more passes 2 passes + 2 mandatory further passes after the first, 2 passes etc. One cannot say in general which better because this depends on one's aims. E.g., if the aim is shortest procedure on the rules level, then one would choose 2 passes. E.g., if the aim is to always allow each player a pass as a ko threat while a pass does relieve ko bans sufficiently, then one might choose 3 passes. E.g., if the first pass generates a conditional compensation and one wants to allow each player the filling of 1-sided dame regardless, then one might choose after the first, 2 passes. Etc. white is alive [under] rulesets with positional superko if black has not enough eyes left to fill as ko threats? If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Why would you be disgusted? The so called 1-eye-flaw occurs in much less than 1 of 10,000,000 games on the 19x19 board. In the entire history of go, it is reported to have occurred exactly once on the 9x9 board. Why do you dislike rules that enable something possible in theory but never occurring in practice? What do you have against 1-eye-flaw staying on the board at the game end? a) That it is a group with only 1 eye, b) that it is a group with only 1 ko, or c) that there is a string with only 1 liberty? Discussion of (a), (b), and (c): All rulesets used by humans allow games to end with groups with only 1 liberty. Example: # O # . # O . O # O # O # . # O . O # O # O # . # O . O # O # O # . # O . O # O . O # . # O . O # . This example shows two stable anti-sekis. By symmetry, it would be superfluous to prolong the game to dissolve either. If you are disgusted by 1-eye-flaw, then you should be even more disgusted by anti-sekis. I.e., you are disgusted by all rulesets currently used by humans. Strings with 1 liberty at the game end can also occur in hane-sekis, double ko sekis, quadruple kos, etc. Maybe you would human rules to be changed by ca so called greedy rule like A player may not pass if there is at least one string with exactly 1 liberty on the board. Such would dissolve all those disgusting things. One can even be more brutal in rules design like dissolving all those disgusting ordinary sekis, too. :) If you want to criticise positional superko, then state your first order aims! Which are they? I hate 1-eye-flaw!? Why should one particular shape be that all-important while we do not know some 100^500 other shapes yet? List them all, and then tell us what makes 1-eye-flaw so special :) More importantly, why are you worried about a shape at all? Shapes are the consequences of move-sequences and strategic decisions, see http://home.snafu.de/jasiek/j2003.html for a basis with that I defined eye formally. Write down your disgusting rules with such a design to enable yourself to define particular shapes in the first place so that you won't overlook any of your potentially hated disgusting shapes... BTW, positional superko IS accepted in some human rulesets like Chinese, Simplified Ing, or World Mind Sports Games 2008. -- robert jasiek ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo
Re: [computer-go] Ending games by two passes
[EMAIL PROTECTED] wrote: In my opinion the goal of a ko rule is to prevent games from not ending. All restriction rules (about suicide, cyclic repetition, successions of passes) contribute to that goal. Ko rules do so by restricting cycles, succession of pass rules do so to avoid very long encores. 1: [1-eye-flaw], 2: [triple-ko,...] Is it mathematically impossible to construct a ko rule that allows 1 and avoid 2? [...] superko. It is overly restrictive. In principle, everything can be expressed by rules. E.g., both 1 and 2 can be avoided by the following, not overly restrictive restriction rules combination: - the basic ko rule as the 2 move rule (i.e., passes serve as ko threats) - the fixed ko rule (A play may not leave position A and create position B if any earlier play has left position A and created position B.) - 3 ending passes The effect is that 1-eye-flaws can be removed, triple-kos are not fought, and triple-kos can be removed (one side is dead!). Fine in theory but nobody likes my very efficient invention :( Maybe you? -- robert jasiek ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
On Oct 24, 2008, at 11:23 AM, Erik van der Werf [EMAIL PROTECTED] wrote: On Fri, Oct 24, 2008 at 4:57 PM, Robert Jasiek [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: In my opinion the goal of a ko rule is to prevent games from not ending. All restriction rules (about suicide, cyclic repetition, successions of passes) contribute to that goal. Ko rules do so by restricting cycles, succession of pass rules do so to avoid very long encores. 1: [1-eye-flaw], 2: [triple-ko,...] Is it mathematically impossible to construct a ko rule that allows 1 and avoid 2? [...] superko. It is overly restrictive. In principle, everything can be expressed by rules. E.g., both 1 and 2 can be avoided by the following, not overly restrictive restriction rules combination: - the basic ko rule as the 2 move rule (i.e., passes serve as ko threats) - the fixed ko rule (A play may not leave position A and create position B if any earlier play has left position A and created position B.) - 3 ending passes The effect is that 1-eye-flaws can be removed, triple-kos are not fought, and triple-kos can be removed (one side is dead!). Fine in theory but nobody likes my very efficient invention : ( Maybe you? I guess more people would like it if triple-kos and other non-abusive long cycles would lead to a tie. Erik I'd prefer to see them treated luke a seki. I'd only want a tie if the capture cycle changed the score back and forth between B+0.5 and W+0.5 ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
Erik van der Werf wrote: I guess more people would like it if triple-kos and other non-abusive long cycles would lead to a tie. For that purpose one can use different rules: - 2 or 3 play rule (applies to basic ko and sending-2-returning-1) - pass lifts 2-move cycle ko ban rule - long-cycle-tie rule - 3 ending passes -- robert jasiek ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
In message [EMAIL PROTECTED], Jason House [EMAIL PROTECTED] writes On Oct 24, 2008, at 11:23 AM, Erik van der Werf [EMAIL PROTECTED] wrote: On Fri, Oct 24, 2008 at 4:57 PM, Robert Jasiek [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: In my opinion the goal of a ko rule is to prevent games from not ending. All restriction rules (about suicide, cyclic repetition, successions passes) contribute to that goal. Ko rules do so by restricting cycles, succession of pass rules do so to avoid very long encores. 1: [1-eye-flaw], 2: [triple-ko,...] Is it mathematically impossible to construct a ko rule that allows 1 and avoid 2? [...] superko. It is overly restrictive. In principle, everything can be expressed by rules. E.g., both 1 and 2 can be avoided by the following, not overly restrictive restriction rules combination: - the basic ko rule as the 2 move rule (i.e., passes serve as ko threats) - the fixed ko rule (A play may not leave position A and create position B if any earlier play has left position A and created position B.) - 3 ending passes The effect is that 1-eye-flaws can be removed, triple-kos are not fought, and triple-kos can be removed (one side is dead!). Fine in theory but nobody likes my very efficient invention : ( Maybe you? I guess more people would like it if triple-kos and other non-abusive long cycles would lead to a tie. Erik I'd prefer to see them treated luke a seki. I'd only want a tie if the capture cycle changed the score back and forth between B+0.5 and W+0.5 This implies that someone or something is capable of calculating the score. But a cycle can occur long before the endgame makes the score calculable. Nick -- Nick Wedd[EMAIL PROTECTED] ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
[EMAIL PROTECTED] wrote: Is your unpopular invention equivalent to situational superko? You underestimate my creativity! :) Test the fixed ko rule by applying it to some shapes. Here is the most basic application: . # O . # O . O . # O . start . # O . # O 1 O . # O . legal . # O . # 2 # O . # O . legal . # O . # O 3 O . # O . illegal Since the fixed ko rule lets all(!) known kos be fixed (therefore its cute name!), we also need the basic ko rule to have at least all our standard ko fights and to avoid that a basic ko would equal an eye in an ordinary tsumego situation. -- robert jasiek ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
RE: [computer-go] Ending games by two passes
After reading up a bit on this issue, I didn't find a clear positive consensus in this list about a preferred ruleset for computer-go, human-computer-go, real life go and go servers. (I did find a negative consensus about the current Japanese rules, though) I'm curious if there exists a positive consensus about a particular ruleset from the point of view of a go software user who is also very familiar with real life go playing (so not from a mathematical or pedagogical point of view, but from the point of view of a go player playing on a server and/or playing against a bot). This user could prefer area counting or territory counting. Specifically: could the current AGA rules be a serious competitor (http://www.usgo.org/resources/downloads/completerules.pdf)? Dave Van: [EMAIL PROTECTED] namens Erik van der Werf Verzonden: vr 24-10-2008 12:18 Aan: computer-go Onderwerp: Re: [computer-go] Ending games by two passes On Fri, Oct 24, 2008 at 11:47 AM, [EMAIL PROTECTED] wrote: Please correct me if I'm wrong, but are you saying that white is alive with TT-rules (=Tromp-Taylor?) or other rulesets with positional superko if black has not enough eyes left to fill as ko threats? Yes. If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Does it really matter if it is human vs. human games? Why have different (inferior?) standards for computers anyway? Erik ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
RE: [computer-go] Ending games by two passes
On Fri, 2008-10-24 at 19:40 +0200, [EMAIL PROTECTED] wrote: After reading up a bit on this issue, I didn't find a clear positive consensus in this list about a preferred ruleset for computer-go, human-computer-go, real life go and go servers. (I did find a negative consensus about the current Japanese rules, though) I'm curious if there exists a positive consensus about a particular ruleset from the point of view of a go software user who is also very familiar with real life go playing (so not from a mathematical or pedagogical point of view, but from the point of view of a go player playing on a server and/or playing against a bot). This user could prefer area counting or territory counting. I think the current rules CGOS uses are pretty popular for CGOS and I think it's what you get with KGS games played under Chinese rules too. CGOS rules are basically Tromp/Taylor rules but where suicide is forbidden. Suicide makes the game slightly less practical, especially for computers (but it's not a big deal.) Other than that Tromp/Taylor rules shine because they are very intuitively simple to learn and state. Just simple and clean. I'm not an expert on AGA rules but I think it's almost the same. There are tons of simple rule variations, the kind of ko to use, whether to use suicide or not, how many passes to end the game, scoring system, how to deal with handicaps, which komi to use, etc. I think Japanese hurts the game, but even if we confine ourselves to Chinese it hurts the game that there are so many variations of the rules.You cannot really play a game without first negotiating which rules you will be using. - Don Specifically: could the current AGA rules be a serious competitor (http://www.usgo.org/resources/downloads/completerules.pdf)? Dave __ Van: [EMAIL PROTECTED] namens Erik van der Werf Verzonden: vr 24-10-2008 12:18 Aan: computer-go Onderwerp: Re: [computer-go] Ending games by two passes On Fri, Oct 24, 2008 at 11:47 AM, [EMAIL PROTECTED] wrote: Please correct me if I'm wrong, but are you saying that white is alive with TT-rules (=Tromp-Taylor?) or other rulesets with positional superko if black has not enough eyes left to fill as ko threats? Yes. If that's true, I would be disgusted if positional superko would ever be accepted as a rule in human vs. human games. Does it really matter if it is human vs. human games? Why have different (inferior?) standards for computers anyway? Erik ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ signature.asc Description: This is a digitally signed message part ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
Re: [computer-go] Ending games by two passes
On Oct 24, 2008, at 1:07 PM, Nick Wedd [EMAIL PROTECTED] wrote: In message [EMAIL PROTECTED], Jason House [EMAIL PROTECTED] writes On Oct 24, 2008, at 11:23 AM, Erik van der Werf [EMAIL PROTECTED] wrote: On Fri, Oct 24, 2008 at 4:57 PM, Robert Jasiek [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: In my opinion the goal of a ko rule is to prevent games from not ending. All restriction rules (about suicide, cyclic repetition, successions passes) contribute to that goal. Ko rules do so by restricting cycles, succession of pass rules do so to avoid very long encores. 1: [1-eye-flaw], 2: [triple-ko,...] Is it mathematically impossible to construct a ko rule that allows 1 and avoid 2? [...] superko. It is overly restrictive. In principle, everything can be expressed by rules. E.g., both 1 and 2 can be avoided by the following, not overly restrictive restriction rules combination: - the basic ko rule as the 2 move rule (i.e., passes serve as ko threats) - the fixed ko rule (A play may not leave position A and create position B if any earlier play has left position A and created position B.) - 3 ending passes The effect is that 1-eye-flaws can be removed, triple-kos are not fought, and triple-kos can be removed (one side is dead!). Fine in theory but nobody likes my very efficient invention : ( Maybe you? I guess more people would like it if triple-kos and other non- abusive long cycles would lead to a tie. Erik I'd prefer to see them treated luke a seki. I'd only want a tie if the capture cycle changed the score back and forth between B+0.5 and W+0.5 This implies that someone or something is capable of calculating the score. But a cycle can occur long before the endgame makes the score calculable. I mean that after the game is ended and enters scoring. Scoring a seki can be tough for programs, but is part of the rules. Nick -- Nick Wedd[EMAIL PROTECTED] ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/ ___ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
