The Backgammon by UNBALANCE

 I was looking forward to playing “The Backgammon”. After all, it’s by UNBALANCE, the company that created “Crazy Stone Go”, which was the best Go-playing app for Android/iOS before the AlphaGo clones came. I’m still playing most of my Go games with UNBALANCE’s nice app, and so I expected a lot from a backgammon of these developers.

To some extent I was not disappointed. “The Backgammon” is a solid implementation of Backgammon; unlike many of its competitors it features money games and matches up to 15 points, correctly implements  everything including the Crawford rule, allows to try out different moves before committing to one etc.

I like “The Backgammon”’s presentation. Two different nice boards wait for you, nicely rendered on phone and tablet. The menu system is easy to understand and has a clean, professional look.

The wood board on an iPad Pro 

The app offers both online playing (which I haven’t tried - there’s backgammon galaxy and backgammon heroes with XG-based analysis features) and playing against an AI. This AI offers five difficulty levels from “gruesome gruesome beginner” to “beginner”. 

I must confess I’m disappointed by UNBALANCE’s effort to build a Backgammon AI. Other than their Go this is no master. Even on its hardest level 5 it makes obvious beginner mistakes, like doubling with a checker behind a 6-prime, just because it’s 10 pips ahead in the race. Also its checker play is doubtful at times. I haven’t fed a match into XG, but I am very convinced it plays not better than a PR of 20 or so. Here’s a few examples:

Beginner cube handling at work

In the example above, black has a checker on the bar, behind a 5 prime, and has nothing. But because I’m only 9 pips ahead in the race, it accepts my double.

A horrible double blunder on (iPhone)

To increase longevity and give you a challenge, “The Backgammon” includes a “challenge mode”, in which you have to beat every level at 5 different match lengths to earn medals. Unfortunately, though, Level 1 is so incredibly weak that I can’t get myself to try out what happens if I win all medals (it leaves direct shots without any reason).

The challenge mode (iPad pro)

So, if you’re an intermediate player or better, you probably won’t find an opponent that can offer you exciting matches here. But for beginners, this is an acceptable Backgammon that you can have a great time with, for free. “The Backgammon” is purely ad-financed. It shows you ads on the top of the screen, and will show you an ad movie after each match. There’s no in-app purchase to get rid of the ads.

The alternative green board, also nicely rendered

Please note, though, that an app playing on this level cannot teach you to become a better player. Not because there is no tutor mode, and also not because it just doesn’t play well enough to be a good teacher. For this you need e.g. XG mobile, True Backgammon, Backgammon NJ.

Yes! My first 7-point match played with "world champ" rating

 Okay, you probably couldn't care less, still I'm proud as hell.

Played a 7-pt match against XG mobile today, managed to win and not mess up too badly; finished with a PR of 2.03.

Here's my single blunder. Would you have done better?

White to play 42.

It's fairly clear that the 2 should hit with 16/14*. But what to do with the 4? Move on with 14/10 and minimize risk, or play bold and slot with 8/4?

...

Honestly I should have seen that. I'm 62 pips ahead and should have played safe. 16/14*/10 only leaves two shots - 44 and 64. I went for 16/14*, 8/4 and blundered 0.18 of equity.

Still: YAY WORLD CHAMP MATCH! :-)

A seemingly easy position (or: why I love backgammon)

Came across a wonderful backgammon position today (on DailyGammon). At first glance, it is totally trival. All the complications are gone. In three rolls the game will be decided. 

Still I managed to squeeze a blunder of nearly 0.2 equity out of it. After 10 minutes of thinking. With a piece of paper. And a calculator.

That's how mysteriously complicated backgammon can be, even in its most simple positions.

Here we go:

 

White's turn. Cube action?

 

This is a match to 15, score is 2:2.Should white double? Should black take?

I have still not figured out how to solve this one.

What's your suggestion?

 Spoiler starts here.

The trivial part is: 

• if white rolls 44, 55, 66, white wins (1/12 probability)
  
• if white rolls something else, and black rolls a double, black wins (11/12*1/6 probability)
• if white rolls something else, black rolls no double, then black has only a single checker on 1 and will win for sure. Unless white can bear off the three stones in two rolls.
  But how likely is this?

I was black, my opponent (correctly) doubled.

I arrived at the conclusion that I need 25% wins to take, the second dot gave me only 15%. So I need to win about 10% of all games in case 3. Since even with a 21 roll, white still has many combinations to win, I concluded that nearly all 2-roll combinations will bring the three checkers home and passed.

Tuns out, the correct cube action is double/take. In this position, black will win almost 30% of games (28,97%, actually; I even did a rollout).

I still have no clue how somebody might solve this OTB. And I'm still amazed that such a simple position is so difficult to solve.

My first Android review :-) - Backgammon by AI Factory

 Okay, it's time to also review Android Backgammons. I wiped the dust off my old trusty Galaxy Tab S2, and installed my first Android Backgammon in a long time: Backgammon by AI Factory. 

 

Backgammon by AI Factory in action

There's this urban myth about Albert Einstein. It says that he has received poor grades in school, particularly in physics. Actually he has received a grade "6" in physics, but while a "6" is a poor grade in most European countries (an "F"), it is a very good grade in Switzerland, where Einstein went to school.

I had to think of this myth when playing a match against Backgammon by AI Factory (henceforth BGAIF) at its supposedly strongest play level "7". Is this all a big misunderstanding? Is the strongest level maybe "1"? But no, even the text explaining the levels goes into great depth about the two new levels 6 and 7 which use a different, very strong AI.

But look at this, for example (NB this is a screenshot from XG2 that I used for expert analysis):

 

Blue to play 22

 

In this position, a blue checker is trapped behind my 5 prime. It's not so important what blue does with three moves of checkers in his home board. But blue MUST move one 2 as 23-21, hoping to roll a 6 later and get behind my prime. Unless you're a total newbie you immediately sees this necessity.

It turns out that BGAIF didn't. It moved 6-2(2).

 

Blue to play 22, with analysis fro XG2

Not unexpectedly, XG2 considers this a horrible blunder, losing nearly a full point of equity (-0.894, to be precise :-) ). And if you look at the move list on the left side, you see quite a lot of BGAIF's moves marked in red color, because they are blunders.

At the end of my match, XG2 awarded BGAIF the poorest of all ratings: distracted (PR 41,8). This means that you cannot hope to improve your backgammon skills by playing against BGAIF and learning from its moves. You can also not hope to enjoy playing against it if you're not a beginner. It's not playing like the poorest AIs that I've seen, but it's nowhere near the same league as Backgammon NJ, for example. 

I'm a bit mystified how an app can offer seven (!) levels of difficulty, using two different AIs, and the top level plays like a beginner.

For completeness sake: yes, I won the match, even though I played poorly (Intermediate) and luck was on BGAIF's side. 

That said, let's cover the basics of this app: BGAIF offers quite a lot, everything that a newbie to Backgammon might want for playing casual games. It doesn't offer enough for anybody to improve her backgammon skills.

You can play money games or matches, with or without cube. It even supports the Crawford rule of matches. It offers several different board designs, some of which you only get if you have another app from AI Factory installed on your device. While playing it supports you finding the right move by highlighting possible checkers and target points and showing the current pip count. It also features an - unconventional - undo: on the one hand you can completely undo any number of moves, which is cool. On the other hand it doesn't feature the "normal" undo that everybody who plays backgammon seriously needs. Normally, when deciding what to do with a difficult roll, you play around with different moves, do them on the board, examine the position, maybe do some probability math, take the move back, do another one, until you're happy. In BGAIF you move the last checker and your move is done. This is a bit annoying, as the next time to undo is after the computer has rolled and moved.

BGAIF doesn't offer any kind of tutor, but that's okay because the engine's advice wouldn't be too much to learn from.

 

The default wooden board looks fairly good.

 

Ads in BGAIF deserve a special mention: BGAIF is completely free, so it's development is supported by in-app ads. No in-app purchases. The ads are VERY limited to a banner in the top right corner. Kudos to AI Factory for not destroying the game with too obtrusive ads.

Summary: I must say I was disappointed by the AI of this app. 7 levels, and the best one plays like a beginner? That's not good. Apart from that, BGAIF is a fairly decent app with not too many highlights but no critical flaws either. Good for a fun game in-between if you're not an experienced Backgammoner (Backgammineer?).

ps. please note that I don't own an android phone anymore, so I can only review how the app looks on a tablet. A good review should check how the app looks on different devices, sorry, can't do that.

A hidden treasure: Backgammon KG

Apple‘s App Store is like a big ocean. If you‘re a fish who manages to live at its beautiful coral reefs, or at its wonderful famous beaches, plenty of divers will get to see you. But if you live down there in the black depths far below the surface, chances are you‘ll never get into a diver‘s sight. 

Backgammon KG is such a creature from the deepest seas. Unlike companies who have read their SEO (search engine optimisation) books and know how to get their app into your search results, its developer Keith Gould probably just wanted to create a good, free backgammon and nothing else. As a result it is near impossible to get it into your app store‘s view. I‘m regularly hunting for new backgammons, scrolling through long lists of apps, but this one never appeared. Only as a related game to another app it showed up. I downloaded it to my trusty iPhone and was amazed at what a beautiful deep sea fish I had found.

Backgammon KG on an iPad Pro

The thing is: there are many (MANY) backgammon apps on the App Store. But there isn‘t a single one that you can call full-featured without blushing and that is really free. Only this one. Backgammon KG. On the German App Store it has a single (one star “this app is cheating”) rating which suggests that only few people ever tried it.

Graphically it’ fine, but there‘s not too much to write home about; the UI gets the job done, the app has a clean and consistent look, you‘ve got 10 board designs to choose from. But I‘ve seen more beautifully looking backgammon apps. One complaint: sometimes, mostly in the lower row of the board, you have to click slightly left to where your checker should move or it will move one point too far. And a minor complaint: there is no native support of the iPad - it’s using app scaling which makes the app look low-res.

Some of the designs (here: metal) are, well, daring

It’s real strength lies not in its presentation but in its scope and in its price. Backgammon KG is really, actually, totally free. Not free as in “buy 1000 coins in-app to unlock this and that”. Not free as in “whenever you like it least it will confront you with 20 seconds of video to watch or with a blinking ad image. No. Really, actually free. Download it. Play backgammon.

And backgammon it plays. Not the “what doubling cube?” kind of backgammon that half of the apps support. Not the “there is something else than money games?” kind of backgammon. Not the “my developer got the task to build my AI in 10 working days so I play like the ultimate backgammon noob” kind of backgammon. Real, actual, strong backgammon! You can play matches from 1 to 11 points, with Cube, Crawford and everything else working the way it should.

Backgammon KG’s AI uses the same fundamental approach that all the top apps rely on - a neural net based machine learning approach that was trained by millions of self-play games. It shows that the app could have used a few million more of those self-play games. It’s strong, really strong, but not as strong as XG mobile or the BGBlitz inside True BG. I’ve played 4 test matches to 3 points, one myself, one pitting Backgammon KG against the PC program XG2 on an extremely strong level (“roller++”). My conclusion: KG’s checker play is world class level. Not perfect - sometimes an error or even a small blunder creeps in. But good enough for quite everybody to get a good challenge. Cube handling is not as strong; Backgammon KG plays a very defensive cube, missing good cubes quite often. So in the end XG2’s assessment of KG in the four matches was once advanced and expert each, and twice world class. Not bad for a free app.

The little red lamp shows the tutor’s opinion on my move (error!)

Also, the game includes a (nearly) full-featured tutor - great to improve your skills. If you activate the tutor in the settings, you’ll get two things: a little lamp that is white (“perfect”), green (“small error”), yellow (“bigger error”) or red (“blunder”). make a move, see the lamp, and take back/experiment to see what the game recommends. Next to the lamp you’ll find a “Moves” button. Hit it and see all possible moves, ranked from strong to weak, along with two mysterious figures that I haven’t understood.

The tutor’s move list

So to find out the best move, click on the first row and behind the semi-transparent list the move is made. Close the list to see the full thing. Undo if you want to still consider different moves.

I can’t stress enough how cool the combination of a strong AI and a tutor is - apart from reading Backgammon books or watching Backgammon videos of pros commenting pro matches this is the best way to hone your backgammon skills. And while I believe the top apps deserve your investment of around 10 bucks, this one does the job really well, completely free of charge.

One minor gripe: the app doesn’t tutor your cube decisions. This is sad because, at least for me, cube handling is the toughest part of backgammon. To make a proper cube decision you have to assess your winning chances, your / his chances to gammon, the volatility of the board, the likelihood of losing your market next turn. After decades of Backgammoning I still regularly make cube errors on the level of “this has cost you half a point”. But then, Backgammon KG isn’t much better in this respect, so a cube tutor wouldn’t teach you that much.

The default board design 

 

A few more words on features: Backgammon KG includes four playing levels, offers statistics on your playing performance, and tries to keep you motivated by gradually unlocking more board designs whenever you win a game on expert level. For the final “Andromeda” design you have to win 200 games. Not an easy job (though you can cheat by stopping and re-starting the app again and again with your last winning move on the board, but that wouldn’t be appropriate, would it?)

My conclusion: this is one of my top three recommended backgammon apps. True Backgammon costs you good money and offers the most beautiful experience. XG mobile isn’t as beautiful but IMHO a tad bit stronger, and an excellent choice for good money. And Backgammon KG is nearly as good without costing you a cent. Now go ahead and download it, what are you waiting for? :-)

 

Update (Sep 2022): as part of my project to have XG2 rank every app in a big table for easy comparison I've played a few matches against Backgammon KG and analyzed them in XG2. Result: it indeed plays quite strong, at a strong expert level, almost world class - PR 5.7. You hardly find a human opponent that is that strong, and gives you free backgammon teaching.

 

A piece of art, but barely a backgammon: Backgammon Machine

The computer game “Doom” kicked off the whole 3D first person shooter genre. In this classic, you start by selecting a difficulty level. On “I’m too young to die” the game is easy, on “Hurt me plenty” it’s fairly hard to beat, but real men (and women) played it on “Ultra Violence” for a real challenge. This analogy came to my mind when thinking about why a Backgammon like “Backgammon Machine” that doesn’t include the doubling cube is fun to play, but somehow stale compared to the real thing. Checker play offers plenty of fun, but by including the cube you turn the game’s challenges from “hurt me plenty” to “ultra violence”. 

That said, Backgammon Machine is a special app. It’s really, actually, totally completely free. No ads. No in-app purchases, no virtual coins, no “watch this video for <feature>”. Free. And beautiful. Man this app is well designed in its pure and beautiful grey look. Steve Jobs would love it. I love it.

Playing a game of backgammon on the iPad

But its beauty doesn’t stop at only visual appearance. Its user experience is also top notch - the way you move your checkers, how you undo is just perfect. For example: you roll 6/3, move a checker by 6 pips. Now if you tap on this checker, the app will highlight two target places - 6 back (to undo the 6) and 3 back (to turn the 6 into the 3). Very clever, have not seen this anywhere else.

The minimalistic options screen

Concerning features, this is pretty much it. You start a game in “match to 1 pt” mode. You make your moves (enjoyable). It makes its moves. You start another game in “match to 1 pt” mode. And so on. No tutor/analysis, no setup, no matches, no doubling, no exporting, no manual dice, you get the picture :-).

Oh yes, and the UI is so clean that it doesn’t show a pip count. The joys of counting pips by hand (strengthening my “criss-cross pip counting skills”).

But maybe that’s enough. Play against a strong, free AI can be fun, at least for a casual backgammon in between meetings or such, even without matches, without doubling. So all boils down to the question: is the AI any good? The answer is yes and no. It certainly plays a stronger game than the AIs that have been hand-crafted in a rush. It certainly plays a weaker game than then high-end AIs of XG, BGBlitz, BG NJ. 

I‘ve played 18 games so far, and lead 12:6 against the AI. I feel I was fairly lucky sometimes, but I‘ve also seen it going for significant blunders. For example, in a situation where I‘m bearing off against 1 or 2 trapped checkers it moves those trapped checkers home far too early (considering it doesn‘t treat a gammon as 2 points it should wait it out as long as possible). Or take this one:

Backgammon Machine playing a 6/4 opening rather … uhm … unconventionally

This 6/4 opening, according to XG2, is nearly a blunder (losing 0.072 equity). This is way too loose, it will be hard for me to roll something that doesn’t hit, and hit on a point I want to make. Not something an app that claims to play at nearly master strength would do.

Nevertheless this app plays a good game of Backgammon, certainly better than many of the “beginner” level Backgammons out there, and as it’s fast, fun, free and beautiful, it’s great for a fast, casual game of backgammon.

So, just install it and have fun. Just don’t expect too much. I hope the author invests more into self-playing to improve its strength, and into a few more features. Matches would be great.

 

Update (September 2022): As part of my "big table with all backgammon app rating" project I've played a couple of games against the machine, and had them analyze with XG2 on the PC. Seems I was lucky during my review; the app plays a strong expert game, almost world class level. (PR 5.2). Sadly it still has no cube.

 

Strange but fun - Backgammon - offline by SNG CT

This one took me a long time to review. Even after playing 35 games against its four levels of AI, I‘m still unsure what to think about it. One thing is for sure, it‘s not for a serious match of backgammon, one in which you can learn from a superior AI and improve your skills. And it wants to make money by making you watch ads and buy coins. And it doesn‘t shy away from fairly unconventional ideas to achieve this.

But let‘s start with the basics. First off: this is about money games. No matches.

The game pits ou against four difficulty levels. Each level raises the stakes - at the beginning you have to compete with the „beginner“ AI because you can‘t afford the price of admission to play against advanced or expert. After you‘ve selected your level you‘re treated with a screen in which you can enter your bet and your maximum bet. From this it calculates how often you can double. 

It took me a long time to figure this one out. First fun fact: this app called Backgammon doesn‘t know what a Backgammon is. It does know what a Gammon is, though. So it calculates in my example: maximum bet is 50,000 coins, my selected bet is 14,400 coins. If I would double and lose gammon I would lose 57,600 coins which exceeds my maximum bet. Therefore I may not use the doubling cube.

Hint: you want to select a bet that allows you to double because the AI has no clue about how to double well, doubles like a „now I‘ll win for sure“ beginner, accepts doubles it should really, REALLY drop. Easy money.

After these two easy steps, you‘re sent to the actual game.

Two things here: a) for some reason much screen space is invested in showing you and one of many virtual opponents. And b) this layout makes the board tinier than possible,, and there‘s no way of showing it full-screen. No problem on a big iPad screen, but still…On a 16x9 iPhone screen this is no issue.

IPhone.

Apart from this, the user experience playing this backgammon is awesome. Nice undo, unobtrusive  support figuring out which checker can move and where it can move, nice drag-and-drop playing if you wish (I love drag-and-drop in Backgammon because it slows me down a little bit and lets me think if this is really what I want. With click-and-click you move fast. And err fast.. And d&d feels like a real board). The app offers a multitude of beautifully rendered boards.

Part of this game (that I was using only in one game to understand it) is: you can watch an ad to re-roll a poor roll. Yes, seriously. There seems to be a limit to this (3 times per game?), but it tilts the odds massively to your side - getting rid of the two or so biggest anti-jokers will massively make you a favourite.

Here it is: watch and reroll.

If you‘re a reasonably good backgammon player, you won‘t need this feature, though - the AI is nowhere as unbeatable as XG, NG, BGBlitz are. But for mysterious reasons I love playing against those little virtual bots. They cover an interesting “white space”: backgammon apps tend to fall in one of two camps. There’s the bleeding-edge neural network bots that play vastly superior to you, and there’s AIs that some guy had to handcraft by creating a bunch of rules, rules that misunderstand 50% of board positions and play like a beginner. You know, the ones that double against your 6-prime because you’re 10 pips down.

This app claims to use a neural network AI that has been trained a million matches. Maybe that’s not enough, but the AI happens to play well, without the horrible blunders that handcrafted AIs annoy you with, but a bit worse than me (XG calls me “advanced” most of the time, “intermediate” if I don’t focus enough). And strangely, the intermediate AI beats me more often than the expert AI. So, at my level of play, I get opponents that I beat more often than not, but that offer good resistance and challenging games, which probably is what many players want. Your mileage may vary. Oh yes, and I’ve mentioned that it doubles poorly, so the joy (pain?) of figuring out whether to take or drop a difficult double is not something you get in this app.

What else can be said? You can buy virtual chips for real money, and if you’re a beginner you will probably have to do this to keep playing (there’s a daily 1,000 coins bonus, as in many F2P games). You can pay 5 bucks to remove ads or watch a boring ad video after every single game. While playing you’re building up experience, even have an experience level, but I haven’t figured out what this level is supposed to do. The app offers no tutor features of any kind.

All in all, if you like money games, want a good but not too good AI to play casual games against, “Backgammon - offline” might be an app to consider. If you’re a backgammon newbie you might face “out of money” situations, though.