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Learning from mistakes 2: Is it too good to double?

This problem is from yesterday’s XGM match against Ole Nielsen. We are in the 4th game where I’m leading 5-1 to 17 (5-1/17). I hold the cube at 2.

Position 1
Position 1

The pip-count (race) is also strongly in my favor having only 64 pips against Ole’s 81 pips.

It was not at all clear to me what the right cube action was. Let’s try to dig into a deeper analysis of the situation I was faced with.

Match score

When leading a match you want to protect your lead by lowering the variance which in most cases means playing more conservatively with the cube – especially high cubes. More variance will benefit the person trailing because it will be easier to become lucky and turn around the course of the match.

This means that I should be less inclined to double than in money game where match score does not play a role.

Context – no gammon, no prime to jump

Let’s start by looking at another situation, that could arise from our original position, where the cube action is clear.

Position 2
Position 2

White is not behind the prime and there is no way of catching the second checker. White will lose a few games by being hit from the bar but Black will also lose a few gammons. See the theory section for reference positions.

Conclusion 1: It is clear that White has no incentive to play on for the gammon in position 2 and the correct cube action is for White to double and Black to pass both at the current match score and in money game.

Theory

I have two reference positions that are nice to know.

Reference position 1
Reference position 1: White wins approximately 2% gammon
Reference position 2
Reference position 2: White wins approximately 5% gammon

Context – gammon, no prime to jump

Let’s take a look at a position where we can win more gammons but we don’t have the issue of being behind a prime.

Position 3
Position 3

It is clear that we are in a much better position than in position 2. The question is if we should double now or play on for the gammon.

If White catch a second checker there will be a significant amount of gammon in the position. If not, White will jump out and end up in one of two situations.

  1. If Black fans we have the same scenario as dealt with in “Context – no gammon, no prime to jump.”
  2. If Blacks enters the position it will be a clear double for White and depending on the distance between the checkers Black has either a take or pass. See the theory section for reference position.

In scenario two Black’s cube action is as shown below.

Position 4
Position 4: Where White’s checker has to be for Black to take or pass

In either case our cube decision is well defined if we do not double right away.

Conclusion 2: If we hit we play on for the gammon. If we miss we double and let Black decide what to do. By not doubling right away White gets a chance to try to win a gammon.

A good rule of thumb is that you need to win more gammons than you lose games to be able to play on for a gammon (the position is too good to double).

As seen in reference position 4 White will win less than 40% gammon if White hits the second checker (let’s say ~30% in position 3). It will happen ~1/3 of the time giving White close to 10% gammon chances. Another estimate is that white will win position 3 over 90% of the time.

Conclusion 3: The estimates above indicate that White will win ~10% gammon and lose fewer games than that. If White does not double there will be efficient cube action next roll. White should play on for the gammon in position 3. The decision is close though.

Theory

Rule of thumb: If you are in a position where you win if you run by your opponent or lose if you get hit, then

  • you can double if you are 11 away
  • your opponent should take if you are 9 or more away
  • your opponent should take or pass if you are 8 away depending on other factors
Reference position 3
Reference position 3: Black can either take or pass

If you have closed out two checkers you will win ~40% gammon.

Reference position 4
Reference position 4: White will win approximately 40% gammon

Analysis of the original position

Looking at position 1 it is now clear that we are not thinking about playing on for the gammon. If position 3 was just good enough to play on for a gammon then position 1 is definitely not good enough. The question is then if White can double at all.

The fact that our position is not a lot worse than in position 3 it still has to be a clear double and a huge pass for Black. This conclusion is so strong that the match related adjustments does not change anything.

After thoughts

If you made it this far consider leaving a comment with feedback on the style of this blog. If I can make improvements I’d like to hear about it, so I spend the time writing these blogs as efficiently as possible.

Good luck with your training. See you at the tables.

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Learning from mistakes 1: Introduction

Personally I believe that you learn the most from your own mistakes. You made them – you own up to them. This is the first part of a series of blog posts called “Learning from mistakes” (LFM) where I will go into some of the errors I made in serious games.

XG Masters 2018

In Denmark we have a tournament running over the summer where a lot of very strong players attend. The main focus is playing well – not winning. You will get awarded one point for winning a match, one point for having the lowest error rate and one point for giving up the least match winning chances.

Each round is planned individually between players and it is typically played at one of the players home or at a cafe. All matches are recorded by video and later transcribed and analysed by eXtreme Gammon (the best backgammon software available).

Getting back into tournament backgammon

I’m participating in XGM this year with a hope of getting back into playing tournament backgammon again after a break for more than 10 years. In the meantime I have been playing a little bit with the computer and on my phone, but mostly single games and primarily to kill time.

Recently I realized that I’ve been missing playing tournaments a lot. Unfortunately I’m very rusty and have to dedicate myself to work hard on the game to be able to be competitive again.

Main focus points:

  • Spend the time needed
  • Play serious tournaments (record all matches)
  • Understand my mistakes
    • Question everything
    • Make sure to learn something
  • Play matches online to think about backgammon every day
  • Discuss backgammon with strong players.

Personal goals

There are two tournaments in scope. XG Masters 2018 and BMAB UK in September. My main goal is to play below 6.0 (average Performance Rating) in those two tournaments together and below 5.5 in BMAB. My current level is around 6.5 which is unsatisfactory to say the least. I make too many unforced blunders.

My main weaknesses are cube action in general and match play in particular. These are typically the first things that you get out of touch with when not playing for a while.

Next blog

The next couple of blogs will go into the first match in XG Masters that I played against Ole Michael Nielsen yesterday evening. There are plenty of mistakes to learn from…

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My favorite backgammon books

Usually I view a book in the context of the pyramid of understanding. What parts of the pyramid are they focused on? What are they trying to teach me? In this blog I will focus on books that I believe together would give a broad foundation within all levels of the pyramid. These are my favorite backgammon books.

Opening Concepts

This great book was written by one of the top players in the world, Michihito Kageyama and his good friend and Roland Herrera who contributed by making the book very clear and concise in the way everything are presented.

This book is mainly for beginners. I like it very much because it breaks down a position in concepts that can be expressed clearly in proverbs. They give you a way to put a position into words. This in turn gives you an opportunitet to talk about and analyse a position. I did get a few things cleared up myself.

The book mainly discusses the opening phase of the game talking about how to figure out what type of position you are in and what game plan you need.

Beginners and intermediates will benefit most from it but advanced players can definitely also learn a thing or two from it.

This is a must read!

From Basics to Badass

This book is written by grand master Marc Brockmann Olsen who is one of the people behind Backgammon Galaxy. He is trying to provide a platform where you have integrated play and analysis into the same product. Marc’s dedication to backgammon as a skill game is apparent in his approach to his backgammon site. This book is for beginners but it also covers a lot about match play for the intermediate and advanced players.

What I really like about this book is that it gives you some simple concepts that you can try to apply to the game. If you learn them all and manage to utilize them you will be an advanced player. I don’t think there are enough examples in the book but it is also clear that this was not what Marc is aiming for.

This book is to be considered as a list of concepts that covers almost all facets of backgammon. It is then your job to work with the material and get a feeling for each concept and how it interacts with other concepts.

As a stating point for a new backgammon player I don’t think you will find a better book.

Boot Camp

Walter Trice wrote a series of articles for GammonVillage that he put together as a book. This book is supposed to cover all aspects of backgammon which is of course not possible – but this is the best try I have seen so far.

The book is basically for everyone. Yes, everyone. There are so many ideas and concepts that you can find something about everything. Sometimes I feel that the book is not connecting the dots. Some sections are too self-contained and it does feel like the book was not written as a book but first as a series of articles.

I use it as an encyclopedia where I look up ideas if I need one. I can recommend this book to everyone.

Modern Backgammon

The last book I’d like to mention in this blog post is my favorite book from multiple times world backgammon champion and extraordinaire author Bill Robertie. This book is not for beginners at all. I would say that you will start getting something out of it when you reach strong intermediate level.

This book is inspired by the way computer programs play backgammon. Bill set out to put the new concepts and ideas from the computer programs into words that we as humans could understand. The book is very well written and with good structure and many good examples. I believe that this book did the most for my game in helping me understand the over-all goals of the game and how to achieve them in practice.

If you are on your way to becoming a strong player this book might be what you need to advance. I can definitely recommend it to all serious players.