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Topic: Fixing the rules / eliminating draws (Read 12624 times) |
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Fritzlein
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Fixing the rules / eliminating draws
« on: Apr 3rd, 2005, 11:27am » |
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If I remember correctly, we had basically reached a consensus that the repetition rule should be changed to include the player to move, i.e. "a third occurance of the same position" should be changed to "a third occurance of the same position with the same side to move".
At the same time we make that change, however, I suggest we make an additional rule change, one proposed by Bram Cohen on his blog. http://www.livejournal.com/users/bramcohen/15337.html
Bram proposes that a player who loses all eight rabbits should lose the game immediately. That seems so intuitive to me now, I wonder why it didn't occur to me earlier. Wasn't Arimaa intentionally designed not to have any draws? There are very few draws as is, but why not iron out this last little glitch so that there are NO draws? It seems like good PR to be able to say, not that Arimaa rarely has draws, but that it NEVER has draws.
I'm trying to think of a disadvantage of this rule change, and not coming up with much. It doesn't seem that someone who could have won under the current rules is suddenly going to lose when draws are eliminated. If I can't keep my last rabit from being captured, it is improbable that I could later immobilize my opponent. So the rule only means that someone may lose who would have drawn the game under the present rules. Why give them a drawing chance when they have no winning chance?
There might be situations where a player gives up on trying to score a goal, and instead tries to hunt down his opponent's last rabbit or two. But in what type of situation would someone have an army powerful enough to capture all opposing rabbits, but not powerful enough to force a goal? If the rabbit-hunting player had the stronger army, then s/he would probably have won eventually anyway. If the rabbit-hunting player had the weaker army, then how would she/he force the capture of pieces the opponent would be trying desperately to protect? Besides which, capturing the opponent's last rabbit is already highly desirable, so it isn't clear that gameplay would change much if we made it more desirable.
If this rule change alters the feeling of the game at all (and I doubt it will alter it much) it would be to place slightly more emphasis on the rabbits, and maybe create some midgame situations where you wouldn't want to trade a rabbit for a cat, for example. Mostly, though, it would only change things in those rare endgames (see Adanac vs Belbo postal) where both sides have very few rabbits. For these esoteric positions, I think the proposed rule change would improve game dynamics by eliminating possible protracted maneuvering when one side gives up on winning and only plays for a draw.
Besides, I think it in general creates more interesting strategic dilemmas to have the weakest piece be the most important piece. When would it be worth giving up a dog for two rabbits? Only in the endgame, or also in the opening? If getting two rabbits for a dog is often a good trade, what about two rabbits for a horse? Slightly increasing the importance of rabbits would natually create more dilemmas in which human judgement outweighs computer calculation in the long run. Because computers rely heavily on material consideration, to muddy the waters of who is materially ahead would seem to favor humans.
What do folks think of this proposal?
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jdb
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Re: Fixing the rules / eliminating draws
« Reply #1 on: Apr 4th, 2005, 9:15am » |
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Quote:| If I can't keep my last rabit from being captured, it is improbable that I could later immobilize my opponent. |
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Here is my completely unrealistic contrived example.
Gold Pieces:
Rc3,Ec4
Silver Pieces:
ra2,rb2,rc2,hd2,re2,rf2,rg2,rh2
ea1, mb1, hc1, ,de1,df1,cg1,ch1
Gold to Move
However, I agree that it would be a reasonable rule, if a player lost all their rabbits, they lose the game.
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #2 on: Apr 4th, 2005, 1:45pm » |
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Cute example, JDB. It never occurred to me that the size of the larger army could work against it. It's true that this example is not realistic, but it reminds me that I didn't report Bram Cohen's suggestion faithfully. He specifically suggested that if a player loses and wins on the same turn, by abandoning the last friendly rabbit but also capturing the last opposing rabbit, then the moving player wins. That could be extended to immobilization just for the sake of completeness. I challenge you to come up with an example where the weaker side can't save its last rabbit, but could win by immobilization not on the same move. Is there even a contrived example that achieves this?
Arimanator, it doesn't secure a draw to throw away the last of your own rabbits unless you capture the last of the opposing rabbits too. Suicide is no goal defense!
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jdb
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Re: Fixing the rules / eliminating draws
« Reply #3 on: Apr 4th, 2005, 7:40pm » |
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Here are a couple of (barely) realistic cases to consider.
a)
Gold:
Ed4,Re4
Silver:
ed5,re5
b)
Gold:
Ed4,Re4
Silver:
rd5,ee5
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Fritzlein
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Arimaa player #706
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Re: Fixing the rules / eliminating draws
« Reply #4 on: Apr 5th, 2005, 8:45am » |
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on Apr 4th, 2005, 7:40pm, jdb wrote:Here are a couple of (barely) realistic cases to consider.
a)
Gold:
Ed4,Re4
Silver:
ed5,re5
b)
Gold:
Ed4,Re4
Silver:
rd5,ee5
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Those are much more realistic than your first case! But are these examples of how the proposed rule change will convert a winner into a loser? It seems more likely that they will convert what would have been a draw into a win for the first player to move. If that's so, I take these positions as evidence that the proposed rule would be a good thing!
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #5 on: Apr 5th, 2005, 8:49am » |
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on Apr 5th, 2005, 1:07am, Arimanator wrote:A question : what if in order to kill your opponent last rabbit about to goal you have to abandon your last one in a trap. Shouldn't it be considered simultaneous then? because otherwise you lose since your rabbit died first.  |
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This is indeed a somewhat plausible scenario. As I mention above, Bram Cohen anticipated it and suggested that it be a win for the moving player.
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mouse
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Re: Fixing the rules / eliminating draws
« Reply #6 on: Apr 5th, 2005, 8:53am » |
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Now whatabout this position?
1w Ee2 Rh3 Cf2
1b ra8 eh2
Gold to move.
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #7 on: Apr 5th, 2005, 8:55am » |
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on Apr 5th, 2005, 3:57am, Arimanator wrote:I am in a chatty mood today  . I for one, don't think that the change of value of the rabbits as the game progresses will overly complicate matters for the programs, it is already the case in chess were the value of a pawn increases dramatically as it gets close to the endline and the bots wouldn't be very good if they didn't take that into account. |
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Yet for some reason computers still can't play the chess endgame (until it gets under seven total pieces) as well as humans. Why are they worse at the endgame, with its lower branching factor, than they are at the middlegame with its higher branching factor? I contend it is because captures are more rare in the endgame, and because the endgame is all about queening a pawn, which means position is more important than material.
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #8 on: Apr 5th, 2005, 9:07am » |
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on Apr 5th, 2005, 8:53am, mouse wrote:Now whatabout this position?
1w Ee2 Rh3 Cf2
1b ra8 eh2
Gold to move. |
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What about this position? Are you saying that Gold wins under one set of rules and Silver wins under the other? I haven't analyzed the position carefully, but my intuition is that it is draw under the curent rules, whereas Gold can win if capturing the last opposing rabbit is a win, by using his elephant to protect his own last rabbit and hunting down Silver's last rabbit with the cat. If my superficial analysis is corect, then it seems like yet one more argument for changing the rules to avoid draws, wouldn't you say?
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mouse
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Re: Fixing the rules / eliminating draws
« Reply #9 on: Apr 5th, 2005, 9:31am » |
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Sorry the position would win for gold if gold plays the best first move.
instead:
1w Ee2 Rh4 Cf2
1b ra7 eh3
As far as I can see. Under the current rules this will probably be a draw. But if we introduce first to lose a rabbit silver would win eventhough gold got more material.
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mouse
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Re: Fixing the rules / eliminating draws
« Reply #10 on: Apr 5th, 2005, 11:08am » |
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on Apr 5th, 2005, 11:05am, Arimanator wrote:| While we on the subject, why can't we play against a bot or another player on any position we want as the ones for example that have been evoked here ? It could be counted as an unrated game and I am sure would come in handy to put some ideas to the test. You could also replay a game with a change in one move to see how things would have evolved ? I don't see it as such an unreasonable request given that most chess games do it. |
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You can with this link:
http://arimaa.com/arimaa/games/planGame.cgi
I don't think Omar has put it up in the gameroom yet.
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mouse
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Re: Fixing the rules / eliminating draws
« Reply #11 on: Apr 6th, 2005, 10:25am » |
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on Apr 6th, 2005, 12:41am, Arimanator wrote:
That's very nice but would it be possible to use it to play against a real bot, like for instance launch bot arimaazilla on that particular position and see how it would have played? I think that would be a big plus for the education of the dummies like me, and as I said most chess games can be programmed that way so it's not so outlandish. |
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I'm not sure that would be really interesting because a lot of the bots too weak in the end game to play well enough to say anything conclusive. Arimaazilla is deffenitly. Maybe Bomb or Clueless knows enough about the endgame to be usefull.
But in many endgames you will have to search atleast 3-4 full moves ahead. Which would be something like 25+ steps. Jdb and/or Footland have tried there bots on that search dept before but I dont think they were convinced about the results.
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #12 on: Apr 6th, 2005, 6:04pm » |
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Until the ability to play bots form an arbitrary position comes on-line, you can buy the capability (i.e. you can buy the latest version of Bomb) from Smart Games for $20.
http://www.smart-games.com/arimaa.html
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mouse
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Re: Fixing the rules / eliminating draws
« Reply #13 on: Apr 7th, 2005, 4:21am » |
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on Apr 6th, 2005, 1:22pm, Arimanator wrote:Unlike chess you have many many possibilities here even for a couple of moves so using a sparring partner ( to use a sporty metaphor) would come in handy.
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Actually I think the idea of a sparring partner is pretty good. If you could load a position with the tool Omar has produced in such a way that two or more person could see it simultaniusly it would be a great advantages. In that way you could analyse a position in cooperation with somebody else, which could greatly improve the understanding of specific situations.
I just think the sparring partner will have to be a human. Because the bots are just not good enough for that. Given your games against Clueless fast I think if you analyse a position for 5-10 minutes you will most likely come up with a better move than any of the bots.
Thats the great thing about Arimaa compared to chess. If you play chess you can check your position against a computer (or grand master) and it will give you a answer that will be better than any move you can come up with. In Arimaa the bots are not able to give you the best answer. The best players like Fritzlein and 99of9 are more likely to give you a better answer but they dont have the grand master level like the top chess players so you will have to think for yourself and you may sometimes come up with a better move than them. 
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Fritzlein
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Re: Fixing the rules / eliminating draws
« Reply #14 on: Apr 8th, 2005, 12:00pm » |
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on Apr 7th, 2005, 4:21am, mouse wrote:| The best players like Fritzlein and 99of9 are more likely to give you a better answer but they dont have the grand master level like the top chess players so you will have to think for yourself and you may sometimes come up with a better move than them. |
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Very true. One of the great things about Arimaa is that there is no authority. None of us understand the game to much depth. For example, Omar is in the process of proving both myself and 99of9 wrong about the high value of the camel in the opening. I was convinced in my postal game against Omar that I had a material advantage, but I think now I am losing, so either I was wrong about what a camel is worth, or I played badly after trading because I didn't understand the position. Either way, I was not just overlooking a tactical idea, which I do all the time, but deeply misunderstanding something.
Thanks for complimenting my Wikipedia articles, Arimanator, but it is far too early for anyone to "write the book" on Arimaa. As our understanding of the game evolves, what I have written will outdate very quickly. The game is still very open for new ideas, and new understanding. You could be the next one to see something all the rest of us have failed to see. If I tell you "don't put the camel in the back row", you shouldn't pay me any mind, because next year all of us may be doing it.
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