The tutortorial - how to improve your game with the tutor of one of the top backgammon apps

Please note: this blog entry is for beginners who want to improve, not for serious players who know what equities are and how to use them.

Recently on Twitter I suggested to a newbie to use the tutor of True Backgammon to improve his playing strength. And then I realised what a difficult task this will be - the tutors of True Backgammon, XG Mobile, Backgammon NJ all work by throwing a huge number of numbers at you. And you‘re left alone interpreting these numbers.

This is why I‘m writing this tutortorial, a tutorial for the usual tutor. I‘m using True Backgammon and XG mobile as examples. Probably will add other apps (Backgammon NJ in particular) later.

A tiny bit of Backgammon terminology and strategy

It‘s hard to talk about how backgammon tutors work without clarifying some basic terms.

Race: Backgammon is a „racing game“: you roll the dice and race your checkers home, your opponent does the same, and who has them home first wins. If you have less points to cover to come home you‘re ahead in the race. If not, you‘re behind in the race.

Points: a lot of strategy depends on how many checkers you have on a point.

• No checker: both players can still occupy this point.
• * one checker: your checker is a blot that can be hit by your opponent. If he does, it moves to the BAR point, losing all race value it has gained. A blot can be a good thing you create on purpose: if you want to make a point (see below) you can either be lucky and roll a roll that moves two checkers onto that point. Or you risk slotting the point, putting a blot there. If the blot isn‘t hit you can later add another checker to make the point
• * * Two checkers: you have made that point. Your opponent cannot move there, which may hinder him in the race. As you cannot move a checker away from this point without creating a blot such a point is called stripped. 
• * * * three checkers: good to have that - you can use one of the checkers to move to another point without giving up that point. This gives your game flexibility.
• * * * * four or more checkers: this point is too crowded, you should think moving checkers away because they serve no purpose in hindering your opponent‘s race.

Pip Count

As the race is so important, the first figure you need to know is not actually a tutor feature but something that almost all backgammon apps show you: the pip count.

True backgammon doesn‘t show the pip count continuously. You have to touch the menu button to see it In this position my pip count (Mensch - human) is shown as [154], the computer‘s pip count is shown as [142]. This means that I have 154 pips to cover in my race, while the computer only has 142 left. I‘m behind in the race by 12 points. 

This is a first tutor-ish feature as the player who is ahead in the race has to do nothing but bring his checkers home safely to win. He should play conservatively, not risk leaving blots. The player that is behind in the race needs to risk something to catch up. He wants to hit a blot or block to the opponent so he can‘t use a roll and falls back in the race.

Now let’s a look at the actual tutor; here‘s a position in which True Backgammon tells me that I‘ve made a mistake.

Tutors are all about equities and probabilities

White to play 51, not a great roll.

I played 24/23/18. My reasoning was that red has stripped 17,14, 12 points so if the computer hits me it will weaken its position.  Also I have no offensive plan. However, the tutor tells me that I made an „medium mistake“ (sorry for the German texts).

Which brings us to the question: when is a mistake medium? When is it a blunder? When a minor mistake? And how do you measure mistakes at all?

This is an important question because as a beginner you might particularly try to understand why your really big mistakes are such really big mistakes, while giving medium or small mistakes a nod and continuing without digging into them.

Suggestion 1: focus on the serious mistakes, blunders first. You learn most from them.

All serious backgammon programs use the so-called equity, which is a number typically in the range between -1 and 1. 0 means an even game. 1 means you‘re certainly winning a point. -1 wins you‘re certainly losing a point. The equity can be any number in between, and you can imagine that it is determined by playing a large number of games from this position:

Suppose, in your position, you let a strong bot continue playing and finish the game for you. If the bot wins for you, you write down 1 point for you. If the bot wins for your opponent, you write down -1 (if you win gammon, you note 2 points etc).  Now let‘s supposed you do this 10 times and end up with 1, 1, -1, 1, -1, -1, 1, -1, -1, -1. Then you can estimate the equity of your position as 1+1-1+1-1-1+1-1-1-1 = -4/10 = -0.4. And as you know that single games go from -1 to 1 you can conclude you are quite a bit worse off.

Race vs equity

Maybe you‘re rightfully confused now: first I wrote that the race shows who is leading, now I write that the equity shows who‘s winning. It‘s important that both factors count. Have a look at this position.

A position with hugely different pip count and equity (XG mobile)

Here, white has still 135 pips to go, while blue is almost home with only 43 pips remaining. But if you take a look at XG‘s evaluation, you see that white is clearly winning - the equity is 1.013 which means something like „wins for sure, with a small gammon chance“. Why? Because blue can be far ahead, but he won‘t ever get his lone checker on 1 over these six consecutive points blocked by white. White will now continue by slotting and then making the 3 point, the 2 point, the 1 point, and blue can only wait for a very lucky 66 when white starts bearing off. 
 

So the pip count is often a good first approximation of who‘s winning, but the equity is the real thing.

The value of a move is how it affects your equity

If you know the equity of a postiion you can determine the position’s equity before and after different moves. Let‘s take our position with equity -0.4. Assume our superhumanly playing bot would play move A, which changes the equity to -0.3, while it estimates the position after your move with an equity of -0.6.

This means the best move in this position would win you 0.1 points of equity (one tenth of a single game), while your move lost 0.2 points of equity. Your move is 0.3 points of equity worse than the best one (which is a big blunder). And this is exactly what backgammon tutors will show you, along with more figures.

Let‘s examine the True BG tutor for my medium mistake.

True BG stays silent as long as your moves are good. If it believes you made a mistake it will show you a line at the bottom, moving the board up a tiny bit. Hit „details“ for the actual tutor.

Oh man, what a sh…load of numbers! Let‘s examine them one by one. 

Tutors usually show the best moves in a position in a list. They mark the best one and your actual move, and they will throw a lot of numbers at you to find out what the differences between moves are.

First we zoom in on the best move I should have played, which is shown in the top lines of the list, marked blue.

The leftmost number is the most important one: -0.729. It‘s the equity of my position after the best move. Meaning I‘m significantly behind, even if I play the best move, which is 6-5 8-3 (shown in the first row, right part)

As people are better with probabilities than with equities, you get a large number of probabilities below that explain the situation in more detail: 

• I will win roughly 1 in 3 matches from this position (31.1%). 
• The computer will win the other 68.9%. There is no draw in backgammon.
• A number that is often helpful is the one named „G+BG“. This number tells you how likely you and your opponent are to win with a gammon or even backgammon. Here, my opponent is fairly safe from gammons, I will only win 6.3% or one out of 15 games by gammon/BG. My opponent is starting to build up some gammon potential with a 16.7% gammon chance, he will win one in 6 games by gammon.
• Ignore the MWC figure for now - these are the match winning chances for me, which is important for match play, because the evaluation of a position might be different if you‘re playing a long match and leading by far or if you‘re playing a normal game.

You can already learn a bit here, make some interesting observations. If you scroll way up to the position in the first figure, you see that my opponent already made two additional points that my last two checkers have to pass, while I have not yet succeeded to do so. This difference turns into a significantly higher chance to win, and in twice as many gammons.

Now let‘s compare my mistake-ish move.

• My move is only the 6th best move. I managed to not find one of five better moves. Good job.
• The leftmost figure, -0.798, is the equity of the position after my move. In brackets it shows (-0.069) which is the difference to the equity of the best move, ie the equity I‘m losing because I picked the wrong move.
• It then shows my move, 24-23, 23-18
• Below it shows my new winning probability, 32.2%. I‘m 1.1% less likely to win now.
• Also it shows gammon/backgammon probabilities. You can see that my opponent‘s gammon chances have climbed by 10% from 16.7% to 26.4%. That‘s because I‘m leaving two blots for him to hit and build a strong board.

Tutors are no teachers

That‘s pretty much it. That‘s what you get out of a tutor. And if now the realisation dawns upon you that tutors are just a large bunch of numbers that a perfectly playing computer throws at you, and that it‘s hard work to interpret these numbers, then you‘re 100% right. A tutor is no teacher. It won‘t tell you about backgammon concepts like priming, blitzing, back games, flexibility, pure plays. It will just tell you for your current position and for every single move how it affects your winning chances and gammon chances. The rest is up to you.

How to work with a tutor

First, let‘s get this out of the way: a very good way to improve your backgammon is to get a human teacher, or read a good backgammon book that explains what‘s going on in the mind of great players when they look at a position.

An incredibly valuable and totally free starting point is the wonderful annotated match between Kit Woolsey and Jeremy Bagai that you can find on bkgm.com. Two top players and the back then best bot explain why the players made the moves they made and why alternatives would have been worse or better.

Also, please note that even after years of playing backgammon I still sometimes end up in positions where the computer tells me „this was a shitty move, you should have played that“ and I just don‘t find out why. The tutors are valuable tools but won‘t help you always.

With that said, that‘s what you can do with a tutor‘s analysis:

• If you‘re a beginner, I suggest you focus on blunders that cost you more than 0.3 points of equity. It‘s far easier to find out what you did wrong than in moves that only cost you 0.05 points of equity.
• Tutors often allow you to click on a move and see it on the board. Look at the position after your move and after the bot‘s move. What are the key differences?
• Maybe look at other moves that are also close to the equity of the top move. What do they have in common that your move doesn‘t have in common with all of them?
• Look at the gammon/backgammon percentages. Sometimes a key difference is that you greatly increase the chance of losing two points.
• Oh yes, and please trust the computer‘s evaluation 100%. If you‘re a top player you might know about very, very exotic positions where the bot misanalyzes the position. But a beginner can blindly trust the evaluation of a superhumanly strong player like True Backgammon‘s BGBlitz engine or XG mobile. If the bot says your move is shit, your move is shit. :-)

XG Mobile‘s tutor (which is really the same thing)

Here‘s what the same figures look like in XG mobile.

XG Tutor tells me I made a serious blunder

Like True Backgammon, XG will remain silent as long as you‘re making good moves. If you blunder (like I did here with a blunder that cost me 0.12 points of equity) you get this dialog. Hit „show best choice“ for the tutor‘s overview and you see this:

Again, you see a list of the best moves; your move is sorted at the second position. You see the moves and the associated equities; if you click on a move the tutor will show you the winning/losing/gammon/bg probabilities. Click on the little eye and you‘ll see the move on the board.

As you see, it‘s pretty much the same data, visualised slightly differently.

That‘s it for now. I hope you enjoyed reading this and it can help you a tiny bit to improve your backgammon.

Next up: how Tutors help you analyze your cube decisions. I was considering adding this here, but the post is very long already, and cube handling is way more intricate than normal checker play, so maybe beginners should first not worry too much about the doubling cube, maybe even play 1pt matches where the cube doesn‘t play a role.