Backgammon Strategy Guide

You cannot choose your rolls, but you choose what to do with every one of them, and over many games the player who chooses better wins more. This guide covers the plans, points, numbers, and cube decisions that decide those choices. It assumes you know the rules of backgammon.

The Five Game Plans

Pick your plan from the race and the board. Ahead in the pip count, you want to break contact and run; behind, you want to keep contact and wait for a shot.

Running game

Race everything home and bear off first. It is the plan when you lead the race with little contact left, roughly a 10 percent lead or more by one common guide.

Holding game

Keep an anchor on your opponent's 5 or 4-point, your 20 or 21-point, and bring the rest of your checkers home while you wait for them to leave a shot. It is the standard plan when you trail in the race.

Priming game

Build a wall of made points in front of your opponent's back checkers. Six in a row, a full prime, cannot be passed until it breaks, which gives you time to bring your other checkers round.

Blitz

Attack: hit whatever you can and make home-board points so your opponent stays on the bar, aiming to close them out. It usually follows early hits, needs builders within range, and a successful blitz often wins a gammon.

Back game

Hold two or more anchors deep in your opponent's home board and hope for a late shot. It is a plan for when you are far behind, often 70 pips or more, and timing is everything: in a back game, being further behind in the race is an advantage, because it lets you keep your anchors longer. Deep anchors on the 1 and 2-points are hard to time and lose many gammons.

Opening Moves

The first move of a game is never a double, because tied opening rolls are rolled again, so there are 15 opening rolls. Computer rollouts rank the plays for each; the table gives the top-rated play and notes where the next one is almost as good.

The five best rolls, 3-1, 4-2, 6-1, 5-3, and 6-5, all make a point or free a back checker at once. With the rest you choose between a slot, a lone checker placed on a point you hope to cover next turn, and a split, moving one back checker off the 24-point. Splitting early is safest, before your opponent has builders aimed at your back checkers.

The ranking has moved over time. When IBM's TD-Gammon preferred splitting to the traditional slot with 2-1, 4-1, and 5-1 in the early 1990s, experts switched. Later rollouts put the 2-1 slot narrowly back on top, which is why the table lists it first and calls the split nearly equal.

Pip Counting

Your pip count is the total number of points your checkers still have to travel to bear off, and the lower count leads the race. At the start it is 167 for each player: 2 x 24 + 5 x 13 + 3 x 8 + 5 x 6 = 48 + 65 + 24 + 30.

Count in clusters rather than checker by checker: five checkers on the 6-point are 30. Faster still, track only the difference between the two sides, or keep a running total from 167 as the game goes. Our board does not display a pip count, so keep your own count as you play.

Points and Anchors

Your 5-point is the most valuable point on the board. Your 4-point and bar point come next, roughly level with each other, followed by the 3-point, so an early roll that makes the 5-point beats one that makes the 3-point.

An anchor is two or more of your checkers on a point in your opponent's home board. It gives a hit checker a safe place to land and makes being hit far less costly. The best anchor is your opponent's 5-point, your 20-point, which some writers call the golden point: it is hard to prime and it guarantees you an entry number, the 5, against a blitz.

Bill Robertie's advice when you are torn between making an anchor and making a blocking point: make the anchor, because anchors get harder to make as the game goes on. Outer-board checkers that aim at points you want to make are builders; bring them down early so your good rolls have something to make points with.

Blots, Shots, and Bold Play

Before you leave a blot, count how many of the 36 rolls hit it. A blot 6 or fewer pips ahead of an enemy checker is within reach of a single die, a direct shot; further away the hitter needs both dice combined, an indirect shot. The safest distance within 12 pips is 11, which only 6-5 hits.

The counts assume a clear path; points your opponent must jump over with a combined roll can cut them. The steepest drop is from 6 pips, 17 rolls, to 7 pips, 6 rolls.

Whether to take the risk depends on what a hit costs you. Paul Magriel's guide in his 1976 book is to play boldly when you hold an advanced anchor, have more home points than your opponent, have an enemy blot in their home board to aim back at, or have more checkers back than they do. Without those, play safe. Most newer players err the other way and play too safely.

Doubling Cube Strategy

Take if you win at least a quarter of the time. Taking risks one extra point to gain three, so with no gammons and a dead cube the break-even is 25 percent. Owning the cube after you take lowers it to about 20 to 22 percent; gammons against you raise it.

Double when you could lose your market. A market loser is a sequence, your roll then theirs, that turns a position your opponent could take into one they must drop. With no market losers, wait. Doubling too late lets your opponent drop cheaply and costs you the chance to play for two points.

Sometimes you are too good to double. If your opponent would have a clear drop but you have real gammon chances, play on: a gammon is worth more than the single point a double would cash. Our board has no Jacoby rule, so gammons count even when the cube has never moved.

In a pure race, the 8-9-12 rule gives quick guidance. Measure the lead as a share of the leader's pip count: double at 8 percent, redouble at 9 percent, and the trailer should pass beyond 12 percent. It works for races over about 50 pips. In Tom Keith's tests against computer rollouts it was the roughest of the common race formulas; his Keith count, which adjusts for gaps and stacked checkers, made far fewer errors.

Bearing Off and Racing

With no contact left, take a checker off with each die where you can, and spread your checkers across the points rather than piling them on a few. A 6 rolled with your highest checker on the 4-point wastes 2 pips; on the 2-point it wastes 4.

• Against an anchor, clear from the back. Empty your highest points first.
• Avoid gaps. With your 5-point empty, rolls of 6-1 and 5-1, 4 of the 36, can force you to leave a shot.
• Keep even numbers on your highest points so that awkward rolls take two checkers off together instead of leaving one alone.
• You never have to bear off. While another legal move exists, moving a checker down inside your home board can be the safer play.

Beginner Mistakes

• Burying checkers. Playing 6/1 instead of 13/8 early sends a checker to the 1-point, where it does nothing for the rest of the game.
• Stacking. Five or more checkers on one point waste material; about four is the useful maximum.
• Neglecting the 5-point. Make it ahead of other points whenever you can.
• Hitting on reflex. Hit when it improves your position, not simply because you can.
• Ignoring the pip count. Without it you cannot tell whether to race or hold.
• Taking hopeless doubles. Below about 25 percent winning chances with no gammons in play, dropping costs less.