Backgammon Gold (premium) - strong and beautiful but with limited tutor

Summary: world-class engine, beautiful UI, limited tutor, no online gaming whatsoever add up to a package that’s worth the price of admission, if I just knew that price.

Sometimes I feel so sorry for backgammon developers. You build a really strong backgammon, and they destroy your app in the App Store because they feel you‘re cheating. 

So for clarification: in Backgammon, you roll two dice, and as 3/1 is the same as 1/3, there are, overall, 21 different possible outcomes (6/6, 6/5, ... 6/1, 5/5, 5/4, ...). A really strong player, such as Backgammon Gold, will select the move that gives you as its opponent the least number of good rolls of those 21 possible rolls, and itself the most good rolls of those 21. As 99% of us are not good enough at Backgammon to do the same we feel we‘re being cheated. Our rolls so often leave us with only awkward moves. Its rolls so often leave it with great moves. But that‘s because it plays like a world champion. And I don‘t.

That said, let‘s move on to the review. Backgammon Gold gets a lot of „this game cheats“ reviews, and that‘s because under the hood, the well-known very strong engine BGBlitz is doing its job. Like the strongest AIs, BGBlitz bases on neural network technology and will destroy you and me and probably every other human on this planet. However, I had the impression that it doesn‘t handle the double cube properly - once we came into a weird double-redouble cycle in a position where I was clearly winning, and as a result I won my first 15 point match against BG Gold, something I nearly never pull off against the other top notch AIs (BGNJ, XG Mobile). This observation corresponds to the test “bot games” I did between Extreme Gammon (PC, Roller++) and BG Gold. Extreme Gammon found nearly no flaw in BG Gold’s checker play, but some serious flaws in its cube handling. Correspondingly it rates BG Gold sometimes as world class, sometimes only as advanced. 

But that‘s minor complaints - for 99% of us, the playing strength of BG Gold at expert level is more than enough. 

Graphically, Backgammon Gold is no slouch either - several different beautiful boards, intuitive controls, nice animation, and a great „you win“ dialog. All is great. My only complaint: on the iPad Pro, the checkers are a bit too small for the board.

BG Gold on the iPad Pro

Where Backgammon Gold doesn‘t convince me is in the teaching section. The wonderful thing about a Backgammon that plays on this app‘s level is that you can have a world class backgammon player to teach you getting better at the game. And while BG Gold has a tutor mode, this mode leaves much to be desired. I can either see what move it recommends, or see how it evaluates the move I selected, only with a „green / yellow / red“ lamp. Yes, understanding equities is tricky and the various numbers that e.g. XG mobile throws at you require a bit of learning to understand, but once you‘re there they offer much more value. I would love to have an advanced tutor that gives me all the information the game has.

The Tutor. Before you move you can hit the light bulb for a hint. Once you‘ve decided for your move, you get a little traffic light - here „yellow“ probably meaning „not that good but not terrible“. 

How much does it cost? I don‘t know. Right now there‘s a „Backgammon Gold“ on the App Store that is free with in-app purchases of about 18€. There‘s also a „Backgammon Gold PREMIUM“ which is what I have bought, which costs €5,50, and which gives you every in-app purchase? Strange. 

Like XG Mobile, Backgammon Gold is „you against the strong AI“. No multiplayer whatsoever.

Overall you get a lot of enjoyment with BG Gold; to improve your game others are better.

 

Update (Sep 2022): played a few games against BG Gold and transcribed and analyzed them in XG2 on the PC. In these games, BG Gold - albeit using the same BGBlitz that awards True Backgammon superhuman strength - makes some grave blunders with the doubling cube.

Also, it seems that BG Gold only uses BGBlitz in "low power" mode - like all strong engines, BGBlitz performs some looking into the move tree like chess does (ie it can consider things like "if I now play 64 this way and then opponent rolls a 33 and he plays it this way, then if I then roll 21 and play this"...)

Here's an interesting position that shows that BG Gold only uses BGBlitz's "look 1 ply ahead" setting:

 

Here, it's brown's turn to move (upwards). Should he play one checker on the 20 point all the way to the 9 point, or should he move both checkers to the 14 and 15 point?

The correct solution is playing 20/15, 20/14. Playing 20/9 is a -0.132 blunder according to XG2.

Here's what BGBlitz (PC) would play:

Just like XG2 it would move both checkers.

Only if I only let BGBlitz use the lowly "1 ply" analysis, it suddenly moves this:

Ie. the move that Backgammon Gold made.

In the end, XG2 (Roller++ setting) concludes that Backgammon Gold plays on a strong expert level (PR 5.8), which is good, but given that an AI that can pull off superhuman playing inside I'm asking myself "why the .... did they not allow for a stronger setting?" It's like having a Ferrari and only driving it in 1st gear...