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(Message started by: omar on Dec 26th, 2009, 11:08pm)
Title: Arimaa Wikibook featured
Post by omar on Dec 26th, 2009, 11:08pm
The server logs also showed an unusually high number of hits from the Arimaa wikibook. When I looked into it, I noticed that the Arimaa wikibook was selected as a featured wikibook.

http://en.wikibooks.org/wiki/Arimaa

Congratulations to the Arimaa community for the great job on creating the wikibook. I have to give a special thank to Karl and also Greg, because I know they put a lot of effort into it. There may be others who did also, but I am not aware of it, so once again thanks everyone for all your efforts.
Title: Re: Arimaa Wikibook featured
Post by Adanac on Jan 6th, 2010, 1:27pm

on 12/26/09 at 23:08:49, omar wrote:
The server logs also showed an unusually high number of hits from the Arimaa wikibook. When I looked into it, I noticed that the Arimaa wikibook was selected as a featured wikibook.

http://en.wikibooks.org/wiki/Arimaa

Congratulations to the Arimaa community for the great job on creating the wikibook. I have to give a special thank to Karl and also Greg, because I know they put a lot of effort into it. There may be others who did also, but I am not aware of it, so once again thanks everyone for all your efforts.


I looked at Wikipedia today, and I was surprised to see that Arimaa now has articles in 17 different languages!

Czech, Danish, German, English, Spanish, Estonian, Finnish, French, Arabic, Hungarian, Italian, Japanese, Polish, Slovak, Turkish, Chinese, Tamil

Very impressive!  By comparison Chess has articles in 102 different languages and Bobby Orr, the greatest ice hockey player ever, only has articles in 13 languages.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jan 6th, 2010, 1:51pm
I have a bone to pick with the Chinese article on Arimaa for the way they transliterate the game name.  There is a Chinese game superficially similar to Arimaa which we call Jungle Game and they call (literally) "fight-animal-chess".  I believe that the creator of the Chinese article on Arimaa originally made a clever reference to Jungle chess by calling Arimaa "run-animal-chess".  That highlighted the similarity while giving Arimaa its own identity.

Unfortunately, a later editor changed the translation of Arimaa to "Indian-fight-animal-chess".  This is equivalent to the claim that Arimaa is (A) a variant of Jungle Game, which it isn't and (B) that Arimaa is an Indian game, which it isn't.  It is simply a bad translation.

We need to recruit a Chinese speaker among us to rectify the poor decision and reinstate Arimaa as "run-animal-chess".  Unfortunately they will have to be eloquent enough to resist the patriotic impulse of the Chinese to assume that our game is a spinoff of their game, since the Chinese invented everything first.  >:(

reference: http://www.chessvariants.org/other.dir/animal.html
Title: update?
Post by Belteshazzar on Jan 17th, 2011, 12:48pm
While the Arimaa Wikibook is very good, it could stand to be updated to include strategies which have been discovered and refined in the last three years.  There is still a red-linked chapter entitled "Other Attacking Ideas".  Though I have worked on the wikibook a bit, my expertise on Arimaa is too limited to make any substantial revisions.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jan 17th, 2011, 1:42pm
Yes, the Wikibook is way out of date.  And more than modernization, it needs additional examples, particularly of goal attacks and endgames.  However, I am resolved not to edit it any more, because I think there are many community members who could spruce it up.  Please don't think of it as my project or Adanac's project any more.  Don't feel that the current text is sacrosanct; you can clarify, refactor, or delete outright as well as adding.

Editing and expanding the Arimaa Wikibook is a great way to give back to the Arimaa community, and it's a great way to teach yourself.  While trying to write about something, you learn how fuzzy your ideas are, and can sharpen your own understanding considerably.

My current contribution to the community is trying to maximize the number of games for which I give live commentary.  Feel free to take anything I say in commentary and work it back into the Wikibooks!  :)
Title: Re: Arimaa Wikibook featured
Post by mistre on Mar 14th, 2011, 9:31am
Who has info on the last 3 Arimaa Challenges - 2008-2010?  It was a very interesting read for 2004-2007 and it would be good to have a complete description of the events before too much time goes by and these games are forgotten.  I would be willing to help out if needed.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Mar 14th, 2011, 11:15am
It would be nice to have the Challenge reports up to date, but I have already forgotten what happened.  Just the other day I was seeing on Wikipedia that I beat Bomb with a camel handicap, and I had no recollection how I had done it or why I felt sufficiently confident to try.  Boy howdy, that seems like another lifetime now that we can't beat sharp at even games.   Anyone who wants to tell that story is probably going to have to look at the games themselves, hope the games have comments, look for historical threads in the Events section of the forum, and for the last year or two see if there was live chat saved in the archive.  I think it is too late to create reports from memory; it must primarily be a distillation from hard records that already exist.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Apr 25th, 2011, 11:30pm
I have been trying to update points of strategy, and I'd like confirmation on whether I'm being accurate.  Is it in fact now the dominant opinion that, with the board full, a camel is worth less than a horse plus a cat?  Here is the page in question: http://en.wikibooks.org/wiki/Arimaa/Relative_Value_of_Pieces#Opening_Trades

Also, I wasn't sure what to do with this:

Quote:
A relatively common material sacrifice in the opening is to sacrifice a rabbit in order to gain a horse held hostage by a camel. It is common in part because there is no consensus who has gained in the exchange, so players will still gladly take either side of the position.

I'm not sure that I've ever seen this done.  Is there now a consensus one way or the other?
Title: Re: Arimaa Wikibook featured
Post by Adanac on Apr 26th, 2011, 6:24am

on 04/25/11 at 23:30:53, Belteshazzar wrote:
I have been trying to update points of strategy, and I'd like confirmation on whether I'm being accurate.  Is it in fact now the dominant opinion that, with the board full, a camel is worth less than a horse plus a cat?  Here is the page in question: http://en.wikibooks.org/wiki/Arimaa/Relative_Value_of_Pieces#Opening_Trades


Thanks for taking the initiative to clean up the Wikibook!

I don't believe that statement reflects the dominant opinion.  I think most players would either slightly prefer a camel over a horse + cat or consider them equal.  It's only on a depleted board that having two weaker pieces is clearly better than having the extra camel.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Apr 26th, 2011, 9:02am

on 04/25/11 at 23:30:53, Belteshazzar wrote:
I'm not sure that I've ever seen this done.  Is there now a consensus one way or the other?

It's funny, but I don't see a rabbit sacrifice to gain camel-holding-horse-hostage as much as I used to.  It happened in my 2010 postal mixer game against Hippo: http://arimaa.com/arimaa/games/jsShowGame.cgi?gid=150713&s=w but I don't recall seeing it in any of the World Championship games that I watched.  I am not sure why; maybe it is because swarming is so common these days that anyone who has committed a horse just follows it with an avalanche of pieces rather than trying to break the horse free.

I don't know whether there is a consensus or not.  I am curious what Adanac and chessandgo think about the value of a camel holding horse hostage.

Thanks for your efforts of clean up the Wikibook; it's good to have someone manning the fort.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Apr 27th, 2011, 4:41am

on 04/26/11 at 06:24:59, Adanac wrote:
I don't believe that statement reflects the dominant opinion.  I think most players would either slightly prefer a camel over a horse + cat or consider them equal.  It's only on a depleted board that having two weaker pieces is clearly better than having the extra camel.

Thanks, I edited further to reflect this.
Title: Re: Arimaa Wikibook featured
Post by chessandgo on Apr 27th, 2011, 9:05am
I think most players value the M for HC opening trade as more or less equal, indeed. And it's hard to talk about the value of a horse hostage, it can range from a whole horse (if there is a second large material threat) to 0 (if the camel does not have an advanced friendly piece in support, or if this supporting piece is attacked by the enemy camel for example).
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Jun 5th, 2011, 3:39am
A question about this section (http://en.wikibooks.org/wiki/Arimaa/Relative_Value_of_Pieces#.22Even.22_Exchanges).  Shouldn't "is indifferent to" be "wants to avoid" when talking about even trades? Since, for example, a cat-for-cat trade would diminish a dog advantage.


Quote:
*A player who has won a Dog for nothing in the opening would like to trade Camels, Horses, and Dogs but is indifferent to trades of Cats and Rabbits.
*A player who has won a Camel for nothing in the opening is indifferent to all trades, and will instead normally try to win further material outright.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jun 5th, 2011, 12:03pm
I stand by what I wrote, but I don't feel strongly about it.  I notice that FAME and HarLog disagree: FAME slightly likes the equal trade when ahead and HarLog slightly dislikes it.

From a theoretical standpoint, you can make the case that a full board tends to cloud the advantage of having an extra piece.  What's the difference between fifteen and sixteen?  Taking pieces off the board makes it more obvious who has one more, because the side with fewer pieces doesn't have enough to do all the jobs that need to be done.  In chess, the conventional wisdom is that when you are ahead by a piece, you should trade pieces (but not pawns) to make the extra piece count for more, and I can see the logic applying to Arimaa as well.

On the other hand, Arimaa is more under control when the board is full, and increasingly unstable as the board empties out.  I can imagine that a player who is behind would be delighted to make any even exchange, because it sharpens the tactics and makes blunders more common, which creates chances for the trailing side.  So I can see the case for not wanting even trades when ahead.

I expect my endgame experience is too shallow to make a good judgment on this score.  I have focused most of my thoughts and energy on the middlegame, so my intuitions as to what happens when the board thins out are weak.  I wonder what other people think about the kind of even trades Belteshazzar is referring to.
Title: Re: Arimaa Wikibook featured
Post by Hippo on Jun 5th, 2011, 3:56pm
I don't agree with evaluation of trades when holding camel hostage. It's true that piece exchanges makes value of the camel smaller, but defending player has much more difficult task to rotate his phant from defense.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Jun 5th, 2011, 9:40pm

on 06/05/11 at 15:56:27, Hippo wrote:
I don't agree with evaluation of trades when holding camel hostage. It's true that piece exchanges makes value of the camel smaller, but defending player has much more difficult task to rotate his phant from defense.

I think the point is that as a camel loses it value, simply abandoning a camel hostage becomes an increasingly viable option.
Title: Re: Arimaa Wikibook featured
Post by 99of9 on Jun 5th, 2011, 10:36pm

on 06/05/11 at 03:39:44, Belteshazzar wrote:
A question about this section (http://en.wikibooks.org/wiki/Arimaa/Relative_Value_of_Pieces#.22Even.22_Exchanges).  Shouldn't "is indifferent to" be "wants to avoid" when talking about even trades? Since, for example, a cat-for-cat trade would diminish a dog advantage.


I agree with you on this one Belteshazzar.  Once you are up a dog, my cats are weaker than your cats.  That is the main theoretical underpinning of DAPE = Depreciated Arimaa Piece Evaluation.


Quote:
From a theoretical standpoint, you can make the case that a full board tends to cloud the advantage of having an extra piece.

I think that trading down (even trades) will help you to win the game more quickly, and that not trading down will help you to win the game more certainly.  But the question is still what is an even trade.

Imagine dogs and cats ranked below rabbits (to simplify things).  The player who is a dog up has one extra piece to throw into blockades etc.  But that would also be true if he had a cat advantage.  And we think that having a dog advantage is better than having a cat advantage.  Why?  Only because the dog can push around cats.  This advantage is lost if we trade off cats.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jun 5th, 2011, 11:55pm

on 06/05/11 at 21:40:10, Belteshazzar wrote:
I think the point is that as a camel loses it value, simply abandoning a camel hostage becomes an increasingly viable option.

Yes, and part of the reason abandoning the camel hostage becomes more viable is that the tempo can more likely be used to make a goal threat on a thinned-out board.  But Hippo is right that it is harder to free the elephant without losing the camel if you have fewer pieces to swarm with.  I really don't know how to balance that tradeoff.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Jun 9th, 2011, 12:14am
Is it really good to trade dogs when you have a dog advantage?  Is it better to be up one-to-nothing than two-to-one with a given piece? Since the text of the Wikibook already suggested that, I elucidated a bit, but is it accurate?
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jun 9th, 2011, 2:01am

on 06/09/11 at 00:14:33, Belteshazzar wrote:
Is it really good to trade dogs when you have a dog advantage?  Is it better to be up one-to-nothing than two-to-one with a given piece? Since the text of the Wikibook already suggested that, I elucidated a bit, but is it accurate?

For dogs it might not matter much while horses and camels are still on the board, but for horses it is palpable even with camels still on the board.  If I have won a horse for a dog plus rabbit, I would like to trade one of my horses for the opponent's last remaining horse, even though that contradicts the principle of the player with quality wanting to avoid even trades while the player with quantity seeks out even trades.

In this opinion FAME agrees with me while DAPE and HarLog disagree with me.  The biases of the creator are showing through.  :)
Title: Re: Arimaa Wikibook featured
Post by Hippo on Jun 9th, 2011, 6:06am

on 06/05/11 at 23:55:52, Fritzlein wrote:
Yes, and part of the reason abandoning the camel hostage becomes more viable is that the tempo can more likely be used to make a goal threat on a thinned-out board.  But Hippo is right that it is harder to free the elephant without losing the camel if you have fewer pieces to swarm with.  I really don't know how to balance that tradeoff.


Just to document my argument. In my current postal mixer game with Tuks. We started with horse exchange, than Daniel offered me dog to gain camel hostage. I didn't accept that and we traded dogs instead. Seems we both agreed that camel hostage on board with traded horses is more than dog.
Important thing to consider was the camel hostage was on weaker nondevelopped wing with the other wing developped (or may be Daniel just expected me not to accept :)).
Title: Re: Arimaa Wikibook featured
Post by 99of9 on Jun 9th, 2011, 6:58am

on 06/09/11 at 02:01:48, Fritzlein wrote:
In this opinion FAME agrees with me while DAPE and HarLog disagree with me.  The biases of the creator are showing through.  :)

Hmmm... I think I agree with you on this one.  Maybe DAPE needs a tweak.  There is already a parameter which depreciates a piece if the opponent has pieces of equal strength.  I guess that should be increased.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Jun 12th, 2011, 8:44am
From this section (http://en.wikibooks.org/wiki/Arimaa/Introduction_to_Strategy/Rabbit_Advancement#Weaken_goal_defense):

Quote:
In the diagram at left, it is Silver's turn to move, but he is helpless to stop Gold's a6-rabbit from reaching goal in two turns.


Looking at the diagram, couldn't Silver to move have gotten its elephant to the northwest in time to stop the goal?  I figure the c7 gold horse would move west, but shouldn't Silver then be able to either freeze or block it?  Granted, Gold could then clean house around the f3 trap, and things look very good for Gold overall, but is it really a forced two-turn goal?
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Jun 12th, 2011, 11:42am

on 06/12/11 at 08:44:51, Belteshazzar wrote:
From this section (http://en.wikibooks.org/wiki/Arimaa/Introduction_to_Strategy/Rabbit_Advancement#Weaken_goal_defense):

Looking at the diagram, couldn't Silver to move have gotten its elephant to the northwest in time to stop the goal?  I figure the c7 gold horse would move west, but shouldn't Silver then be able to either freeze or block it?  Granted, Gold could then clean house around the f3 trap, and things look very good for Gold overall, but is it really a forced two-turn goal?

Gold's next move will be Hc7w Hb7e ra7e Ra6n.  If the silver elephant freezes the gold horse, the gold rabbit just walks to goal.  If the silver elephant freezes the gold rabbit, then rb7n Hc7w Ra7n wins.  The silver elephant can't get to b7 to freeze both the horse and the rabbit.  I'm really bad at goal attack/defense, though, so let me know if there is something I am not seeing.
Title: Re: Arimaa Wikibook featured
Post by Hippo on Jun 12th, 2011, 12:24pm

on 06/09/11 at 02:01:48, Fritzlein wrote:
For dogs it might not matter much while horses and camels are still on the board, but for horses it is palpable even with camels still on the board.  If I have won a horse for a dog plus rabbit, I would like to trade one of my horses for the opponent's last remaining horse, even though that contradicts the principle of the player with quality wanting to avoid even trades while the player with quantity seeks out even trades.

In this opinion FAME agrees with me while DAPE and HarLog disagree with me.  The biases of the creator are showing through.  :)


HAME agrees as well ... with the value 34 of initial rabbit. RD traded for h is 155 gold advantage and RDH for hh is 200 gold advantage (so more than initial rabbit improvement).
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Jun 12th, 2011, 4:58pm

on 06/12/11 at 11:42:04, Fritzlein wrote:
Gold's next move will be Hc7w Hb7e ra7e Ra6n.  If the silver elephant freezes the gold horse, the gold rabbit just walks to goal.  If the silver elephant freezes the gold rabbit, then rb7n Hc7w Ra7n wins.  The silver elephant can't get to b7 to freeze both the horse and the rabbit.  I'm really bad at goal attack/defense, though, so let me know if there is something I am not seeing.

My thinking had failed to account for the fact that Gold can respond to whatever Silver does.  Silver might choose to bring up its dog in order to unfreeze its other dog and block the western goal, but Gold could counter that by moving its horse west, and Silver wouldn't have time to do anything to stop the goal.  If however Silver tried to bring over its elephant, Gold can indeed pull over the silver rabbit and advance his own rabbit to force a goal on the following turn.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Sep 4th, 2011, 8:56pm
Does this page (http://en.wikibooks.org/wiki/Arimaa/Introduction_to_Strategy/Initial_Setup) accurately explain the main reasons for dogs vs. cats vs. rabbits behind the traps?  I removed a few statements that I am not sure are true, and even if they are I am not sure that a beginner would grasp why.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Sep 4th, 2011, 9:22pm
That edition looks fine to me.  Most of the time it won't make a difference for defending a trap whether there is a dog or a cat behind it, but when it matters it can be the difference between winning and losing.  Look at the ongoing Postal Mixer game between chessandgo and Hippo: if Hippo had had a dog on f7, chessandgo's early attack couldn't have happened.  This motivated the Mob to set up with a dog on c7 against the Gang.
Title: Re: Arimaa Wikibook featured
Post by Hippo on Sep 5th, 2011, 12:54am

on 09/04/11 at 21:22:13, Fritzlein wrote:
That edition looks fine to me.  Most of the time it won't make a difference for defending a trap whether there is a dog or a cat behind it, but when it matters it can be the difference between winning and losing.  Look at the ongoing Postal Mixer game between chessandgo and Hippo: if Hippo had had a dog on f7, chessandgo's early attack couldn't have happened.  This motivated the Mob to set up with a dog on c7 against the Gang.


I am far for thinking I am winning now, but it seemed to me I was winning till (first) blunder.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Sep 5th, 2011, 1:29am

on 09/05/11 at 00:54:18, Hippo wrote:
I am far for thinking I am winning now, but it seemed to me I was winning till (first) blunder.

What move what that?
Title: Re: Arimaa Wikibook featured
Post by Hippo on Sep 5th, 2011, 4:46am

on 09/05/11 at 01:29:24, Fritzlein wrote:
What move what that?

20s was the blunder, I hope there are better options.
At least ee4 ce3 change seems better.

I was not meaning winning, but rather I felt a small advantage.
Title: Re: Arimaa Wikibook featured
Post by Fritzlein on Sep 5th, 2011, 9:37am
Interesting.  I would have thought you were already behind after 10g (and still after 20g), but it is a type of position I am not used to, and I didn't analyze it, so my superficial judgment is likely to be wrong.  Perhaps later chessandgo will tell us how he felt about his position all along.

In any event, whether or not we think the elephant-cat attack was sound, a dog behind the trap would have prevented it.
Title: Re: Arimaa Wikibook featured
Post by Belteshazzar on Mar 3rd, 2012, 9:39pm
From http://en.wikibooks.org/wiki/Arimaa/Introduction_to_Strategy/Distribution_of_Force


Quote:
How the camel should respond to an EH attack is a tricky issue even for humans, but so far it absolutely baffles computers


Is this still true?
Title: Re: Arimaa Wikibook featured
Post by omar on Mar 12th, 2012, 12:34am
Well these days the camel will generally try to take the horse hostage, but it is tricky knowing when and how to take it hostage. I think the bots in the WCC this year do tend to do this. So it's probably not as true as it used to be.


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