Why should I not drop here?

In my last match against XG2, I thought I was clever and XG2 refused to believe that I am. I'm still stunned why my thinking is wrong.

Match to 7, I'm leading 6:4, Crawford game. I roll an initial 62 which I consider poor. XG2 actually agrees, rates my position after that 62 as -0.3. 

XG2 does the automatic double, and I think "well I have three attempts to win that one point, I'm sure I get a better first roll than 62 in one of these two. I drop.

XG2 then tells me I've wasted 0.7 equity and played this like a total beginner. XG2 can be cruel in its assessment of us humans.

The match continued with a next game that I correctly dropped after two unlucky rolls, and a final game in which my first roll was a beautiful 42, so I could start with 8/4 6/4 which is a much better start than the above...

Update: it turns out (thanks to David Startin on Twitter) that my reasoning was, well, flawed. Yes, I only need to win one more game, but a game is more than a good start. So by passing I gave away a match where XG needed to win two games (the first to 6-6, then a final one), the first of which had a mediocre start for me, for a match where I got a better start but XG needed to win only one game, which clearly is a big blunder.

Backgammon HD by Wildcard Classics

Wildcard Classics confronts the user with 3 different Backgammons:

• Backgammon - classic board game - free, 2 in-app purchases (for 2.50€, a Christmas theme and something called Acey Deucey???). Contains ads.
• Backgammon HD which I‘m reviewing here - costs 5.50€, no ads.
• Backgammon Premium, costs 3.50€, offers the in-app purchases as well.

On top, if you use Backgammon HD you can‘t play online against somebody who uses Backgammon - classic board game.

Once you‘re past this confusion (which their website doesn‘t explain, primarily because the URL they provide in the App Store doesn‘t exist), Backgammon HD is a fairly nice game. Not in the same league as the best ones, but good in every respect for casual players.

Backgammon HD offers a beautiful UI with several different skins

Like many Backgammons, BGHD features three difficulty levels - easy/medium/hard. Let‘s have a look at „hard“. It turns out that the app plays a decent game of backgammon. It knows the value of builders, it tries to make points, it hits blots when it should. Of the 11 games I played against it it won one. (I‘m not an expert, btw). 

For confirmation I let XG (PC) play a game against BGHD. BGHD made a good number of correct moves, and a good number of blunders. Not the kind of hyper-blunders that lose a whole game like some other apps I‘ve reviewed lately, but blunders. Not unexpectedly, XG‘s assessment of BGHD was „Beginner“ with a PR of around 30.

If you‘re a casual player and if you look for a good casual player to play fun and challenging games against, this might be your app. If you‘re a Backgammon enthusiast who wants to get better, to learn from your mistakes, it‘s not.

BGHD offers the full backgammon incl. doubling cube. However it feels like the doubling cube was added as an afterthought. Doubling well is an art of its own, and BGHD‘s rule „if you‘re well ahead in the race, double or take“ fails so often so miserably. I‘m winning most of my games at 64 points.

The screenshot above shows the situation after the app re-doubled from 16 to 32. Yes, my pip count is 118 and the app‘s pip count is 104, so it‘s ahead in the race by 12 pips. But I have trapped a stone behind a 5 prime, threatening to make a 6 prime, and it has nothing! This is the time to resign, not to re-double. The game ended with me winning 64 points.

My greatest misses, part 1: a subtle detail on bearing off

Okay, I'm only an advanced level backgammon player dreaming of playing on expert level some day, but maybe my worst blunders can be instructive to other non-pros. 

Here's one you might enjoy. It might be trivial for you, and I'm embarassed that I missed it. I learned - situations that look like "there's only one move so don't even start thinking" are still worth thinking.

 

 

Here I didn't think. It was clear, there is only one checker that can move the 6, so I moved 8-2. Then I needed to move the 4, so I moved 3-off. XG tells me this is a horrible blunder worth half a point (0.44 to be precise). 

The right move is to move the 4 first - 8-4, and then bear off the 6 with 4-off, leaving no blot.

True Backgammon HD - BGBlitz on iOS

Not as old as the real pioneers of computer backgammon, but old enough, there since 2002, and still being developed and performing on top level: the strong backgammon program BGBlitz. For iOS, there are two apps utilizing the BGBlitz engine, and while I wasn't entirely convinced of Backgammon Gold, the second app, True Backgammon HD, shines on iOS, and is a worthy contender for the Backgammon crown on Apple's platform.

 

 

True Backgammon's leather board (iPhone)

  

Visually, and acoustically, TBHD is my most favorite Backgammon for iOS. The leather board above costs €1 in-app, but that's worth it. By default there's a nice wooden board and a just as nice metal board for you to choose. And while the clicking and dice-rolling sounds of nearly every other backgammon sound cheap and cheesy, the ones of TBHD are so enjoyable that I'm actually playing most games with sound on.

 

 

The free metal board. Notice how the triangle shape of the pips shines through the semi-transparent checkers? Nice!

The drawback of this clean, simple, beautiful design is that actually playing is a bit annoying. Want to know who leads in the race? Tap on menu to have the board scroll sidewards and reveal this info. Want to try out different moves (which is absolutely normal in Backgammon, even on professional level)? Tap the menu, wait for the board to scroll to the side, tap undo (you can also just move the pieces back to their previous location, like on a normal board, though).  

Another minor annoyance is the way the game supposedly beautifully scrolls up a bit when offering a double:

 

 

The wooden board, I'm being offered a double

Doubling is a critical, complicated part of Backgammon that requires full concentration. Frankly, it's beyond me why I can't see the full, normal board but only see the top half of the upper row. This might be considered a minor issue, but it's annoying as hell (particularly as my cube handling is vastly inferior to my dice handling, so I really need to concentrate there).

Moving the checkers on a tablet is a wonderful matter. You grab a checker and move it to its destination with a well-done drag-and-drop implementation. You can even drag-and-drop back and forth when trying out different moves, like on a real board) and multi-drag several checkers. By now, TGBG supports different ways to move, on devices of all sizes. I like drag&drop most because it feels nearly like a real board.

Yes, these are no major issues, but TBHD costs somewhere between €4 and €15 depending on your in-app spending habits. You need at least the basic game (€3.50) and the BGBlitz AI features (€6). At this price of admission I expect a rather flawless app.

 

 

For a Tron-ish Backgammon experience download a neon board (in-app purchase €1). Here I'm being offered a hint by the tutor.

 

If you purchase the BGBlitz tutor for about €3 (in-app), and you should, because an AI that destroys you without telling you where you're failing is a frustrating experience, then TGHD will give you the usual insights into your errors and blunders. This is nicely done, shows everything you get out of the other top-notch mobile AIs.

This is what it looks like: it tells you the preferred move + all the equities and probabilities that backgammon fans need to understand the evaluation. Also the game shows you visually on the board what the best move would have been. Same for doubling. And with BGBlitz being fairly strong, these hints can help a lot to tune your mental pattern matching abilities.

As we're at it: how strong is the app, exactly? I analyzed quite a few games with XG2 on the PC (roller++); result is that it plays about as good as the best humans on their very good days. It performs at a PR rating of about 1.5 to 2.5. Similar to BG NJ, slightly inferior to XG Mobile's super-human strength of about 0.5 PR. But honestly: you'll never notice. BGBlitz in this app makes no errors that are worth mentioning, and it will teach you to avoid your errors just as well as XG Mobile.

Just to be sure you take this with the right grain of salt: A low PR means better. World-class players manage to get a PR below 4. The currently strongest human player has a PR of 2.4. TBHD has a PR of somewhere around 1.8. It plays significantly stronger than any human can play.

It's a difference if you don't invest the money for the BGBlitz in-app purchase. XG rates me as an "advanced" player with a PR of about 11, and I'm soundly beating TBHD's free built-in AI on its hardest level. For newbies the AI is sufficient but don't expect to learn anything, improve your backgammon, or maybe get your mind blown by a state-of-the art AI destroying you over and over and showing you that luck plays a much lower role in Backgammon than you thought.

 

 

The (also) beautiful oriental board, scrolled to the left to make place for the menu.

For the sake of completeness: the app offers two-player "share a device" gaming and network gaming. I havent' tried out both. The app comes with pretty much all rules, but I haven't found Jacoby/Beaver. You can play money games or tournaments of every normal tournament length.

Double-clicking on the match score will open a "export and mail match as sgf". However often XG2 and/or gnu bg can't import the sgf due to some errors in the file. Hoping for a fix.

My summary: this is a great backgammon. With some small tweaks (maybe an "undo" / "show pip" gesture; single-click move on iPhone, different way to show "double?" dialog) it would be the best of the best. As it is, it's the backgammon of choice if you want the most beautiful top-notch backgammon on an iPad. If you want to play not only a world champ but a superhuman AI, go for XG mobile. If you like post-mortem analysis on the device, go for BGNJ.

Update: in the last months, TBHD has received a couple of great new features that catch up with XG Mobile. I particularly like the new game / match statistics (German here, unfortunately) that show you precisely how well you were doing in the current game and match, and whether the dice gods were looking down on you approvingly or punishing you with bad luck :-)

As a result, I‘m playing nearly all my “bot matches” with TBHD; the beautiful board, the nice drag and drop, the strong engine, and the insights in a single package are better than the competition.

Disclaimer: I’m not affiliated with the developer of TBHD, but after my first review he contacted me, took my suggestions seriously, implemented them, and I acted as a tester for them. So I might be more enthusiastic about the app than if I were completely neutral. I consider this just an additional feature: the developer cares and listens. (I’ve got different reactions to feedback I gave to other apps…)