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Arimaa

arimaa
A couple of weeks ago (or was it sooner - ah: link) XKCD did a comic about the likelihood of computers beating humans at various games, noting the dates computers first beat human chess champions (and the last time human chess champions beat computer ones) and concluding that Calvinball was pretty safe from AI conquest for a while.

I recognised most of the games mentioned, apart from Mao and Arimaa. So I looked those up. Mao is the sort of game you need your social circle to grow up with, I think, as it's a secret rules game that relies on everyone apart from their victim being in on the joke (like Mornington Crescent if played maliciously). Arimaa though sounded like fun.

According to the Wikipedia entry, and confirmed by reading more about it further, it was invented specifically to be easier for humans than computers and as a reaction to computers beating people at chess. The relationship with chess was constantly referenced, and the website for the game says you can either play it with your chess set or buy a boxed Arimaa game for £30. (Uh, or a less boxed, more bespoke one for over a hundred).

I read how it is playable with a chess set, and didn't like that so much. The pieces in Arimaa are hierarchically arranged, strongest to weakest: Elephant, Camel, Horse, Dog, Cat, Rabbit - and there's one each of Elephant and Camel per side, 8 Rabbits and two each of horses, dogs and cats. But on a chess set, the knight isn't third tallest, so the suggested substitution was to use Rooks for Horses, and use the Knights as Cats.

I'd been thinking it'd be possible to play it with Holly, as the rest of the rules were quite short (it'd been invented by a father and son, and the animals picked to be an easy theme for kids). But I knew that the piece that looks like a horse not being the Horse would confuse her, and we'd need to be able to easily see which piece was stronger than which other piece. In Arimaa the animals all move the same way - no diagonals, one square per step (though Rabbits can't hop backwards) so all we really needed to do was have their order obvious. The online rules also go into a lot of side-notes about the maths, or computers and chess, all of which seemed likely to decrease readability for Holly.

I edited down the rules to about 330 words, taking out "adjacent" and "orthogonal" and so on. And as there was no downloadable print'n'play pieces on the website I had a look around online. The only thing I could find was animal silhouettes to glue onto glass counters, and those looked great but not so much for a eight-year-old learning a new game.

What's a geek to do? Fire up Excel, of course.

Wikimedia sure has some nice animal pictures from out-of-copyright encyclopaedias. (c:

My pieces. Both sides look yellow under this light, oops!By then I'd downloaded the app for the iPhone, and was very pleased to find that after three games I beat the computer opponent for the first time (I downloaded the free with one easy opponent version, ideal for learning the game). Previously I'd always installed chess on phones or PDAs because I wanted something stimulating but this suffers from the fact that I suck badly at chess. I'd start every game to see how long I'd last, rather than to win. So here was a strategic game I could beat. Result!

The rules are really quite simple. They're hard to summarise down further than the following paragraphs:

There's two sides, Gold and Silver, and an 8x8 squared board like chess or draughts. It doesn't need to be chequered though because no-one cares about the diagonals. It does need the four squares three-in from each corner to be marked as "traps".

Gold sets up their pieces on the two rows closest to them, in any order they like. Silver then does the same on the two rows closest to them. This means Silver sees how Gold sets up before they decide how to - this balances for Gold going first. Generally people put all or most of their Rabbits on the back row because they're the most vulnerable pieces.

A turn is made up of 4 or fewer steps. On each step you move one of your pieces one square forwards, backwards, left or right - apart from Rabbits which cannot move back (unless being pulled or pushed). The four steps can be used to move more than one piece. You can use fewer but when your turn ends the pieces must be in different places from the start.

After any step a piece on a trap with no "friendly" piece on one of the 4 squares next to it is removed/captured.

The order of the animals is important because stronger pieces pull, push, or freeze weaker ones. Elephants bully everyone except each other, and Rabbits bully no-one - tying for strength does nothing!

Pushing and pulling take two steps. To pull, move your piece one step, then drag the enemy from next to where your piece was onto that square. To push, move the enemy next to your stronger piece to an empty square, then put your piece where it had been. These are the most complicated bits in the whole rules, but once you've understood them, you've pretty much got the entire game sussed.

Weaker enemies are frozen by your stronger piece beside them unless they also have a friendly piece next to them. Frozen pieces cannot move unless pulled or pushed.

To win you either get one of your Rabbits to the last row at the opposite side or capture all the enemy Rabbits.
And that's about it. There's a full version of the rules at www.arimaa.com and they're issued under a public license for non-commercial stuff provided people mention that they're under a public license and that there's a full version at arimaa.com. (tick!) The first tutorial over there is really pretty clear - it's in Flash and nicely laid out. The second tutorial appears to be a more bells and whistles version of the first. There's also a good (and amusing) youtube video of how to play, but it's clearest in the tutorial.

I made the board by drawing an 8x8 grid on a piece of A3 green card, cutting out the traps and then sticking red card behind it. The printshop on the high-street laminated it for me, so total cost including white and yellow card for the pieces was probably less than a fiver. It not looking like a chess set was a specific goal - I don't think the game needs the framing as it's not very chess like in play.

If you want to print your own pieces, here's the file I bodged together. The bases interlock in the usual way for cardstock pieces. They're not all different heights, but they do vary in width too so it's fairly easy to see what outranks each other.

So far I've played only one game with the set. I've won plenty on the iPhone, have won several on the Arimaa website against the ladder of increasingly more cunning bots, but yes - lost to Gail in the game where I showed her how the rules work with my home-made set. (c:

I'm enjoying playing it a lot. I'm going to have a go at teaching it to Holly next.

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Comments

( 6 comments — Leave a comment )
bethanthepurple
Jan. 23rd, 2012 01:38 pm (UTC)
That looks really fun. I'm just a bit miffed that it doesn't exist on Android Marketplace to download.
yoyoangel
Jan. 23rd, 2012 01:55 pm (UTC)
Sounds cool!
eatsoylentgreen
Jan. 23rd, 2012 05:38 pm (UTC)
adjectivemarcus
Jan. 23rd, 2012 10:39 pm (UTC)
Thank you, not sure what LJ did to my link but it's fixed now.
rosefox
Jan. 23rd, 2012 06:09 pm (UTC)
I grew up playing Mao and loved it. The way my crowd played it, it was much more of a memory game: whoever remembered the rules best was most likely to win. We played at the fastest possible pace to make it harder. Attempting to play it without knowing the rules was so incredibly awful that we didn't even try; we just encouraged newcomers to watch us play until they thought they had the hang of it, and we gave them hints as needed (e.g. "Penalty! Failure to name the correct member of the Beatles or of Metallica when playing a 4" rather than "Penalty! Try again".) I still have dozens of decks of cards just waiting to be shuffled together into one giant Mao deck.
eatsoylentgreen
Jan. 23rd, 2012 10:54 pm (UTC)
ooh I want to get a Mao circle going!
( 6 comments — Leave a comment )