(I'm not affiliated with this product, just sharing information.)

A few months ago. Rémi Coulom's Crazy Stone engine had drawn quite a bit attention when it played at 4-5d on KGS. A Windows version was released around the time, but they also promised an iOS version for the iPhone. I finally discovered it a few days, although they apparently renamed it to "Champion Go" for the iPhone. For AppStore standards, the price tag of $7.99 is relatively steep, but it's still much cheaper than the PC version and not too far off from other Go playing apps.

Information and screenshots:
http://itunes.apple.com/app/id450726575?mt=8

I picked it up and have been playing on the iPad in x2 mode. It's a little fuzzy, but definitely usable. It supports 9x9, 13x13 and 19x19, three different input modes (zoom, cursor and touch), 10 different levels of playing strength on the 19x19 board (on 9x9 and 13x13 there are 5 difficulty settings), byoyomi for the player (I actually use and like this to force myself to play slower, but not too slowly), and it can both save and export (via email) SGFs.

And it has "medal challenges"! Altogether there are 150 medals that you can earn by playing against the bot on different board sizes, difficulty settings and komi/handicap setups. 100 of them are for 19x19, and 25 each for 9x9 and 13x13. Granted, this is a bit gimmicky, but it provides motivation and offers a challenge with "trackable" progress. It's tad video-game-y, like "achievements", but yes, I'm having fun earning medals and play the bot more than I would without these trophies. It also sets this app apart from others of its kind, and it's "something to do".

An upgrade to a universal version with retina/HD graphics would be lovely, as would be a multiplayer feature with GameCenter support, but the latter is quite possibly beyond the app's scope! (Ironically, the prettiest board and stones I have seen on the iPad/iPhone are featured by an app that doesn't even play Go: Connect6, which is quite fun and very pretty, but it's not Go.)

Thx, also, there's an Android version but I couldn't find it on the android market until I emailed myself this link to the market place https://market.android.com/details?id=jp.co.unbalance.android.go then opened it on my Android device with the marketplace option (linked to from the CrazyStone website http://remi.coulom.free.fr/CrazyStone/). - and by Android device I mean Asus transformer tablet - runs fine, Japanese language only. Finding the option to increase the strength to level 10 was easy enough though (which ran at a decent enough speed).

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I am John. John-I-Am.

Just an update on this:

They've release a native iPad version of the app/bot now, with HD graphics. Unfortunately, they opted for two different versions of the software instead of releasing an universal app that runs on all devices, adapting to the specs available. The HD version includes all of the features of the iPhone version plus additional, stronger CPU modes, one of which is aimed specifically at the dual-core processor of the iPad2 (it does work on the iPad1 as well, just takes longer to move). I really can't judge the playing strength accurately myself, but others have estimated 1-2k on 19x19, which for a mobile version is pretty darn good.

The HD version sells for €5.99. I grumbled a bit about having to basically buy it a second time, but at the end of the day it's little money for what you get, and the graphics do look nice on the iPad.

(I'd love a Go app with GameCenter and multiplayer support.)

.. and they released an English language android version which I bought as well as the original Japanese one. The English one is now on sale.

p.s. they have a pretty nice Shogi app too.

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I am John. John-I-Am.

I downloaded the android version and I like it so far. They should have expanded upon the medals idea though. Having timed tsumego medals for example would be a nice feature.

I now own all 3 versions of crazy stone (pc, iphone (though I played it on my ipad), and now ipad version).

The pc version I was very impressed with. Like some who purchase all published go books I tend to purchase most computer playing software. Crazy stone was clearly a level above the previous generation (such as go++ and many faces of go) and I just now am able to beat it at level 6 (out of ten).

The iphone version was a disappointment, though I was not surprised. These MC engines need cpu cycles and a phone only has so many. I easily beat it on level 10 (my guess is it plays at about 6-7kyu, I am about 3-4kyu).

The ipad HD version is a definite step up from the iphone version. I played today against it at level 12, me at about 80%, and it solidly beat me. 1-2kyu est. sounds about right. Not as strong as the PC version but all things considering not to bad.

Here is the game.

It's on sale right now for $1.99 too!

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Bravado Waffle Studios
Twitter: @bravadowaffle

That's the one thing I really like and really dislike about the AppStore: So many publishers and developers do sales, and so frequently, that there is almost no point in ever buying an app at the regular price. (Then again, everything is so cheap compared to PC software that it nearly doesn't matter.)

There's an app for that. Appshopper watches apps you choose and sends you a notification if one goes on sale.

I actually didn't see the sale--saw it at 7.99 this evening.

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Occupy Babel!

The iphone version is $1.99 but the iPad version is $7.99.

I'm still trying to decide between Crazy Stones HD and Igowin HD. In the meantime I keep losing to Smartgo.

Champion Go HD (CrazyStone) gives you more value for the money, though I quite like Igowin HD as well. They have different playing styles, so they complement each other nicely. But feature-wise, Champion Go offers more and is also likely to be the stronger engine at the highest settings. Both are good and more satisfying to play against than a bare bones Monte Carlo engine!

There's a recent update that allows you to play in "engine server mode", and it's even stronger (I think the server playing remotely is the one used by crazy stone, 5D on KGS). But this "engine server mode" requires an in-app purchase for playing, around 3$ a month.
Anyway, it's very strong.

Could anyone tell me exactly how strong the engine server is? could be 2d+ on KGS on slow games?

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-xiangz, the author of EasyGo for iOS

The strength of the program when playing as a bot on a remote computer will depend of the power of that computer. If we are looking at the bot playing on KGS, then it appears to be playing at about 5 dan KGS. That's what we are talking about here, using the iOS program on your iphone to play against the bot.

I am fairly sure that if you ontained and installed Crazy Stone on a reasonably current computer (as opposed to phone or small tablet) it would be at least 2 an KGS. If installed on a powerful current computer (with say an i7-2600 or E3-1270) I would not be surprised by 4 dan KGS (as these would benchmark at about half of Remi's machine that the bot runs on).

The issue of playing speed is complex. Although they are objectively weaker playing very fast than at normal playing speed the computer has an advantage over humans when the human has no time to read things out. Thus the programs have a slightly higher rating (vs humans) at blitz speed compared to normal speed. But if we kept increasing the amount of time beyond normal this effect would vanish. The computer program would keep getting (objectively) stronger though with rapidly diminishing returns while the human would max out; having read thoroughly more time does not spot errors made reading.

Mike, thanks.

I asked the question because I'm interested in playing with the server engine on my iPad. I mean the paid subscription service by Crazystone. Anyone tried the subscription service? How's the stength? And is it possbile to load SGF to the server engine to continue playing? and can the game be paused at any time?

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-xiangz, the author of EasyGo for iOS

I have played against the server version. I would guess its around 3dan or 4dan on kgs scale.

$80 for PC version?!?
I don't even know what to ask to see if it's worth it.

Most of the top-end chess engines I've seen are around the £90 mark. Yeah it's a lot of money but it's a combination of the amount of effort needed to create these combined with the small markets for them that give you such prices.

The IOS version crazy stone is pretty weak