How are the dice Generated?

Dice on XG Mobile are generated using Mersenne-Twister seeded randomly each time the program starts. This is a very robust system that passes all existing randomness tests.

Does it cheat?

A common question that is asked about any backgammon program (no matter how strong) "is does it cheat?". First let us say clearly that the answer is "NO". We are a serious company and our backgammon products are used by the best players in the world. Many of them train constantly on eXtreme Gammon. If these top players believe that eXtreme Gammon is playing fair, maybe you should consider their expert opinion.

The goal of software like XG mobile is to both provide entertainment and also accurate information to the player. We have nothing to gain by making the program cheat: you are the only one seeing the results. This is why there are weaker levels (Advanced, intermediate, beginner) that can be selected if the player wants an easier challenge.

If you play XG Mobile at higher level, you will lose often: XG-Professional plays as well as the best player in the world. XG-Champion is even stronger. However, if you turn on the Tutor and follow its advice you will see that you will win a lot more.

I emailed support about my concern about the dice, why didn't I get an answer?

By experience, we know it is almost impossible to convince someone that believes that dice are biased that it is not the case. Trying to do so usually results in many back and forth emails that end up being the big waste of time both for us and the user. For that reason, no complaints about the dice will be answered. The extent of our position about the dice is explained in this page

How to use the App

How to roll the dice?

To roll the dice just tap anywhere on the screen. If playing in 2 player mode you must tap the right side of the board (assuming both players are sitting face to face)

How to move the checkers?

How to move the checkers?

Tap a checker to move it using the active dice (the left most one if both are active). To invert the active dice, tap any dice.
How to play
Drag a checker to the destination you want. You can drag back a checker you already moved to cancel a move.
How to play
Double tap a point that is empty or occupied by one opponent's checker to move two checkers to that point.
How to play

How to cancel a move?

To cancel a move, use the cancel button (top left). It will cancel the last part of the move. You can tap and hold to cancel several moves. You can also drag back a checker you moved to another location.

How to Double?

To double, just tap the doubling cube. You can also use the cube button the toolbar. The program will ask for confirmation before proceeding. To accept a double, tap either the "take" or "pass" button. If Beavers are allowed you have a third option to beaver (immediately redoubling but retaining the cube)

Computer Level

How strong are the different levels?

Champion plays noticeably stronger than the top players in the world (PR=0.55). It will make a small mistake every 4.5 games and a blunder every 90 games.
Professional plays stronger than the top players in the world (PR=1.32).
Expert plays as strong as the top players in the world (PR=2.06).

How does the XG mobile level relate to eXtreme Gammon (desktop) levels?

XG Mobile Neural network and implementation is very similar to the one on eXtreme Gammon. However, there are slight differences and it very slightly weaker: XG mobile champion plays at a PR of 0.55, while eXtreme Gammon 3-ply equivalent plays at PR 0.50.

Champion is equivalent to 3-ply
Professional is equivalent to 2-ply
Expert is equivalent to 1-ply

Why eXtreme Gammon (desktop) stronger levels are not available in XG mobile?

eXtreme gammon strongest level (XGRoller++) would surely be nice to have on Android, iPhone and iPad. However, at the current time, these devices are not powerful enough to handle the huge amount of calculations needed for these levels. XGRoller++ is 450 times slower than 3-ply (Champion). On an iPad 2, it would take about 4 minutes to get an answer.
In the future, as the devices get faster, and if we can find better way to optimize for ARM processor, maybe these levels will find their way to Android, iPhone and iPad.

Exporting Saved Games

Can I export the game I play to analyze them on my PC or Mac?

Yes, if you have the premium version, the games will be saved upon completion of each game in the documents folder.
You have 2 ways to retrieve these files: use iTunes or use the export feature in XG Mobile (See Below)

How to export using iTunes?

Open iTunes, connect your device and select it in the list. Then go on the "App" tab, Scroll down to the bottom of the panel to the "File sharing" section. Select "XG Mobile" in the list of Apps. The Saved Games will be shown in the "XG Mobile Documents". Select the file you want and use the button "Save to..."

How to export using XG Mobile?

Click on the menu icon (Bottom left corner) and click on Export. Use "Email saved games". Pick the files you want to send and use the "email" button.

When I try to send email, I get an error?

You need to configure your device for emails. See Apple site for details.

What is the format of the files?

The files are saved in MAT (JellyFish) format (when emailing files, they will be saved as TXT to avoid any problem with email program blocking MAT files). These files can be imported in eXtreme Gammon but also in Snowie, GnuBG and BgBlitz.

Premium Version

How do I purchase the Premium version?

The upgrade to Premium is done using the "In-App purchase" system. If you have disabled "In-App purchase" for parental security you will need to enable it again. There are several ways to access the payment page: using the button "Premium Version (upgrade)" on the loading page, From the About dialog or several of the settings dialogs.

Is the premium purchase transferable?

In-App Purchases are tied to your Apple ID. This means you can restore the purchase on your new device at no cost. Just use the "restore purchases" button when you reach the payment page.

I've an iPad and an iPhone; do you need to purchase XG mobile for both?

In-App Purchases are tied to your Apple ID. This means you can restore the purchase on your new device at no cost as long as both devices use the same Apple ID. Just use the "restore purchases" button when you reach the payment page

I've two android devices, do you need to purchase XG mobile for both?

In-App Purchases are tied to your Google Play ID. This means you can restore the purchase on your new device at no cost as long as both devices use the same Google PlayID. Just use the "Restore" button when you reach the payment page.

Setting Up a position

How do I setup a position?

You can enter the setup mode by first closing the current game from the "menu" icon (bottom left) and then use the "setup a position".

The icon bar inside the board shows in order:
- The active checker color, this is the color of the checker you will add to the board. Tap on the icon to switch the color.
- The player on roll, tap it to invert it.
- Two buttons to change the current cube value.

Tapping on point will set checker of the active color; you can drag up and down to add or remove checkers. You can slide your finger left or right to add the same amount of checker on adjacent point.

Tap a die to increase it by 1. If it's already at 6 it is changed to 1. You can invert the dice by tapping the arrows in-between the dice (however, this is purely cosmetic).

Hints, Tutor and Analyze

What is Simple Hint?

This is the default setting of XG Mobile. When you ask for a Hint it will display arrows to show what is XG Mobile's suggestion. As you play the checkers the arrow will disappear. If you play differently than the suggestion arrows will be removed.
When the hint is visible, if you tap again the hint icon the suggestion will be played automatically.

Cube decisions hints are displayed as circles around the correct choice or an arrow to indicate to roll the dice.

What is Extended Hint?

You can switch to "Extended hint" by going to the Setting Dialog. Click on "Game options", and unselect "Simple Hint".
Extended hint will display all the choices (top 5 moves for a checker play) and their Equity. It allows you to quantify the differences between choices.

Equity is a concept used in Backgammon to quantify a position. An equity of +1.000 means the player on roll will win for sure a single game. An equity of -1.000 means he will lose a single game. Equities can be larger than 1 when gammon are possible (an Equity of +2.000 means a sure gammon in unlimited games).

What is the tutor mode?

The Tutor mode is a very good way to improve your backgammon skills: as you play, XG Mobile verifies your move and alerts you of any mistake. You, then, have then a chance to reconsider your choice, get a Hint, or play your move anyway.
Reconsider the move and try to find the correct one is a very good exercise. If after a few attempts you still cannot find the correct move, ask for the hint. Playing the move anyway is also interesting as it can allow you to see the consequences of the faulty move.

What is the PR?

R stands for Performance Rating. It is a number that quantify the skill of a player. The lower the PR, the better the skill. Top players in the world average a PR around 2 to 3. Player entering live tourney (open level) are around 5 PR.


How do I change the Settings?

Tap on the Menu icon (Bottom Left) and select "Settings". This will give you access to the setting window.

I am playing in 2-player mode, for the player on top, messages are displayed upside down?

By default, XG Mobile assumes that you use the device in 2 player mode by placing it in between the 2 players. For this reason, the messages for the top player are upside down so he can read them easily. For the same reason, the pip count gets inverted with the turn (or for take decision).
If you wish to play side by side, you can disable that setting: go in the "Settings" view and tap "Game options". Uncheck the slider called "Rotate Messages in 2 player mode".