Backgammon is a simple game with deep strategic elements. It does not take
long to learn to play, although obscure situations do arise which require
careful interpretation of the rules. The playing time for each individual game
is short, so it is often played in matches, for example the first to five
points. Game and match are used in Backgammon to refer to these distinct
elements, as in, “I won two games in a row, but then she won three in a row
and I lost the match, three points to two.” In short, players are trying to
get all of their pieces past their opponent’s pieces. This is difficult
because the pieces are scattered at first, and may be blocked or captured by
the opponent’s pieces. Each side of the board has a track of twelve adjacent
spaces, called points and usually represented by long triangles of alternating
(but meaningless) color. The tracks are imagined to be connected across the
break in the middle and on just one edge of the board, making a continuous
line (but not a circle) of twenty-four points.
The points are numbered from 1 to 24, with checkers always moving from
higher-numbered points to lower-numbered points. The two players move their
checkers in opposite directions, so the 1-point for one player is the 24-point
for the other. Some recorded games, however, keep the numbering of the points
constant from the perspective of one player. Each player begins with two
checkers on his 24-point, three checkers on his 8-point, and five checkers
each on his 13-point and his 6-point. Points one to six, where the player
wants to get his pieces to, are called the home board or inner board. A player
may not bear off any checkers unless all of his checkers are in his home
board. Points seven to twelve are called the outer board, points thirteen to
eighteen are the opponent’s outer board, and points nineteen to twenty-four
are the opponent’s home board. The 7-point is often referred to as the bar
point and the 13-point as the mid point. At the start of the game, each player
rolls one die. Whoever rolls higher starts his first turn using the numbers on
the already-rolled dice. In case of a tie, the players roll again. The players
alternate turns and roll two dice at the beginning of each turn after the
first. After rolling the dice a player must, if possible, move checkers the
number of points showing on each die. For example, if he rolls a 6 and a 3, he
must move one checker six points forward and another one three points forward.
The dice may be played in either order. The same checker may be moved twice as
long as the two moves are distinct: six and then three, or three and then six,
but not nine all at once. If a player has no legal moves after rolling the
dice, because all of the points to which he might move are occupied by two or
more enemy checkers, he forfeits his turn. However, a player must play both
dice if it is possible. If he has a legal move for one die only, he must make
that move and then forfeit the use of the other die. (If he has a legal move
for either die, but not both, he must play the higher number.) If a player
rolls two of the same number (doubles) he must play each die twice. For
example, upon rolling a 5 and a 5, he must play four checkers forward five
spaces each. As before, a checker may be moved multiple times as long as the
moves are distinct. A checker may land on any point occupied by no checkers or
by friendly checkers. Also it may land on a point occupied by exactly one
enemy checker (a lone piece is called a blot). In the latter case the blot has
been hit, and is temporarily placed in the middle of the board on the bar,
i.e., the divider between the home boards and the outfields. A checker may
never land on a point occupied by two or more enemy checkers. Thus no point is
ever occupied by checkers from both players at the same time. Checkers on the
bar re-enter the game through the opponent’s home field. A roll of 1 allows
the checker to enter on the 24-point, a roll of 2 on the 23-point, etc. A
player with one or more checkers on the bar may not move any other checkers
until all of the checkers on the bar have re-entered the opponent’s home
field. When all of a player’s checkers are in his home board, he may remove
them from the board, or bear them off. A roll of 1 may be used to bear off a
checker from the 1-point, a 2 from the 2-point, etc. A number may not be used
to bear off checkers from a lower point unless there are no checkers on any
higher points. For example, a 4 may be used to bear off a checker from the
3-point only if there are no checkers on the 4-, 5-, and 6-points. A checker
borne off from a lower point than indicated on the die still counts as the
full die. For instance, suppose a player has only one checker on his 2-point
and two checkers on his 1-point. Then on rolling 1-2, he may move the checker
from the 2-point to the 1-point (using the 1 rolled), and then bear off from
the 1-point (using the 2 rolled). He is not required to maximize the use of
his rolled 2 by bearing off from the 2-point. If one player has not borne off
any checkers by the time his opponent has borne off all fifteen, he has lost a
gammon, which counts for twice a normal loss. If a player has not borne off
any checkers, and still has checkers on the bar and/or in his opponent’s home
board by the time his opponent has borne off all fifteen, he has lost a
backgammon, which counts for triple a normal loss. Sometimes a distinction is
made between pieces in the opponent’s home board (triple loss) and pieces on
the bar (quadruple loss)
The doubling cube
To speed up match play and to increase the intensity of play and the
need for strategy, a doubling cube is usually used. A doubling cube is a 6
sided die that instead of the numbers 1, 2, 3, 4, 5, 6 on it, has the numbers
2, 4, 8, 16, 32, 64 on it. If a player believes his position to be superior he
may, before rolling the dice on his turn, double, i.e., demand that the game
be played for twice the current stakes. The doubling cube is placed with the 2
side face up to show that the game’s value has been doubled. His opponent must
either accept the challenge or resign the game on the spot. Thereafter the
right to redouble (double again) belongs exclusively to the player who last
accepted a double. If this occurs, the cube is placed with the face of the
next power of 2 showing. The game rarely is redoubled beyond 4 times the
original stake, but there is no theoretical limit on the number of doubles.
Even though 64 is the highest number on the doubling cube, the stakes may rise
to 128, 256, 512 and so on.
Beavers
A common rule allows beavers - the right for a player to immediately
redouble when offered the doubling cube, while retaining the cube instead of
giving it back up. (The redouble must be called before the originally doubling
player rolls the dice.) In this way, the stakes of the game can rise
dramatically. Beavers are commonly allowed when backgammon is played for money
game by game, and usually not allowed in matches.
Jacoby Rule
The Jacoby Rule makes gammons and backgammons count for their respective
double and triple points only if there has been at least one use of the
doubling cube in the game. This encourages a player with a large lead in a
game to double, and thus likely end the game, rather than see the game out to
its conclusion in hopes of a gammon or backgammon. The Jacoby Rule is widely
used in money play, but is not used in match play.
Crawford Rule
The Crawford Rule makes match play much more fair for the player in the
lead. If a player is one point away from winning a match, his opponent has no
reason not to double; after all, a win in the game by the player in the lead
would cause him to win the match regardless of the doubled stakes, while a win
by the opponent would benefit twice as much if the stakes are double. Thus
there is no advantage towards winning the match to being one point shy of
winning, if one’s opponent is two points shy! To remedy this situation, the
Crawford Rule requires that when a player becomes one single point short of
winning the match, neither player may use the doubling cube for a single game,
called the Crawford Game. As soon as the Crawford Game is over, any further
games use the doubling cube normally. Not quite as universal as the Jacoby
Rule, the Crawford Rule is widely used and generally assumed to be in effect
for match play.
Automatic Doubles
When Automatic Doubles are used, any re-rolls that players must make at
the very start of a game (when each player rolls one die) have the side-effect
of causing a double. Thus, a 3-3 roll, followed by a re-roll of 5-5, followed
by a re-roll of 1-4 that begins the game in earnest, will cause the game to be
played from the start with 4-times normal stakes. The doubling cube stays in
the middle, with both players having access to it. The Jacoby Rule is still in
effect. Automatic Doubles are common in money games (upon agreement). They are
never used in match play.
Three Basic Strategies
In very general terms, there are 3 basic strategies employed. You need
to be able to switch strategies instantly as the course of the game unfolds.
The Blockade
This involves building a 6-thick wall of checkers, or at least as
thick as you can manage, to block in the opponent’s checkers that are on your
1-point. This is considered to be the most suitable strategy at the start of
the game. You can build the wall anywhere between your 11-point and your
2-point and then shuffle it into your home board as the game progresses.
The Blitz
This involves closing your home board as quick as possible while
keeping your opponent on the bar. For example, if your opponent rolls an early
2 and moves one checker from your 1-point to your 3-point and you then roll a
5-5, you can play 6/1 6/1 8/3 8/3. Your opponent is now in serious trouble
because they have 2 checkers on the bar and you have closed half your inner
board!
The Backgame
This is where you have 2 or more anchors in your opponent’s home
board. (An anchor is a point occupied by at least 2 of your checkers.) It
should be used when you are significantly behind as it much improves your
chances. The best places for anchors are towards your opponent’s lower point
and either on adjacent points or with a single point in between. Timing is
crucial for an effective backgame: after all, there’s no point having 2 nice
anchors and a solid wall in your own home board if you are then forced to
dismantle this straight away, while your opponent is getting their checkers
home, because you don’t have other spare checkers to move! In this case, it’s
better to have checkers on the bar so that you can preserve your position
until your opponent gives you a chance to hit, so it can be a good idea to try
and get your opponent to hit them in this case! Some people go for a backgame
from the outset, but this is a mistake. The backgame is a losing strategy:
it’s just that this strategy makes you less likely to lose if you are already
losing!