Rules to the game of backgammon
- A Backgammon board or layout.
- Thirty round stones, pr checkers, 15 each of two different colors,
generally referred to as `men'.
- A pair of regular dice, numbered from 1 to 6. (For convenience,
two pairs of dice, one for each player, are generally used.)
- A dice cup, used to shake and cast the dice. (Again, it is more
convenient to have two dice cups.)
- A doubling cube---A six-faced die, marked with the numerals
2,4,8,16,32 & 64. This is used to keep track of the number of
units at stake in each game, as well as to mark the player who
last doubled.
Backgammon is an obstacle race between two armies of 15 men each,
moving around a track divided into 24 dagger-like divisions known as
``points''.
The Backgammon layout is divided down the center by a partition,
known as the ``bar'' (See Diagram 1), into an outer and inner (or home)
board or table. The side nearest you is your outer and home tables;
the side farther away is your opponents outer and home boards. The
arrows indicate the direction of play.
For purposes of convenience we have numbered the points in the
diagram. Though the points are not numbered on the actual board,
they are frequently referred to during play to describe a move or a
position. Your (X's) 4-point or 8-point will always be on your side
of the board; your opponent's (O's) will always be on his side of
the board.
A move from your 9-point to your 5-point is four spaces (the bar
does not count as a space). A move from White's 12-point to your
12-point, though it crosses from his board to yours, is but one
space, for these two points are really next to each other.
Diagram 2 shows the board set up ready for play. Each side has
five men on his 6-point, three men on his 8-point, five men on his
opponent's 12-point, and two men, known as ``runners'', on his opponents'
1-point. The runners will have to travel the full length of the
track, the other men have shorter distances to go. Note that play
proceeds in opposite directions, so that the men can be set up in two
ways. Turn the diagram upside down to see the layout if play were
proceeding in the other direction.
+-------------------------------------------------->
|
| +-----------------------------< X moves this direction
| |
| |
| | 13 14 15 16 17 18 19 20 21 22 23 24
| | +------------------------------------------+
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | | | | | +----+
^ v | Outer Board |BAR| Home Board | | 64 |
| | | | | | +----+
| | | P O I N T S | | . . . . . . | Doubling
| | | . . . . . . | | . . . . . . | Cube
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | | . . . . . . | | . . . . . . |
| | +------------------------------------------+
| | 12 11 10 9 8 7 6 5 4 3 2 1
| |
| +---------------------------------------------->
|
+---------------------------------< Y moves this direction
Diagram 1 (Numbered from X's point of view)
13 14 15 16 17 18 19 20 21 22 23 24
+------------------------------------------+
| X . . . O . | | O . . . . X |
| X O | | O X |
| X O | | O |
| X | | O |
| X | | O | +----+
| |BAR| | | 64 |
| O | | X | +----+
| O | | X |
| O X | | X |
| O X | | X O |
| O . . . X . | | X . . . . O |
+------------------------------------------+
12 11 10 9 8 7 6 5 4 3 2 1
Diagram #2 (Numbered from X's point of view)
The object of Backgammon is for each player to bring all his men
into his home board, and then to bear them off the board. The first
player to get all his men off the board is the winner.
Each player casts one die. The player with the higher number makes
the first move, using the two numbers cast by his die and his
opponent's. In the event that both players roll the same number, it
is a standoff and each rolls another die to determine the first move.
In the event of subsequent ties, this process is repeated until the
dice turn up different numbers. (In some games, players double the
unit stake automatically every time they cast the same number; others
limit the automatic doubles to one. In tournament play, there is no
such thing as an automatic double.)
Each player's turn consists of the roll of two dice. He then moves
one or more men in accordance with the numbers cast. Assume he rolls
4-2. He may move one man six spaces, or one man four spaces and
another man two spaces. Bear in mind that, when moving a single man
for the total shown by the two dice, you are actually making two
moves with the one man---each move according to the number shown on
one of the dice.
If the same number appears on both dice, for example, 2-2 or 3-3
(known as doublets), the caster is entitled to four moves instead of
two. Thus, if he rolls 3-3, he can move up to four men, but each move
must consist of three spaces.
The players throw and play alternately throughout the game, except
in the case where a player cannot make a legal move and therefore
forfeits his turn.
A player makes a point by positioning two or more of his men on
it. He then ``owns'' that point, and his opponent can neither come to
rest on that point nor touch down on it when taking the combined
total of his dice with one man.
A player who has made six consecutive points has completed a
prime. An opposing man trapped behind a prime cannot move past, for
it cannot be moved more than six spaces at a time---the largest
number on a die.
A single man on a point is called a blot. If you move a man onto
an opponent's blot, or touch down on it in the process of moving the
combined total of your cast, the blot is hit, removed from the board
and placed on the bar.
A man that has been hit must re-enter in the opposing home table.
A player may not make any move until such time as he has brought the
man on the bar back into play. Re-entry is made on a point
equivalent to the number of one of the dice cast, providing that
point is not owned by the opponent.
A Player who has made all six points in his home board is said to
have a closed board. If the opponent has any men on the bar, he will
not be able to re-enter it since there is no vacant point in his
adversary;s home board. Therefore, he forfeits his rolls, and
continues to do so until such time as the player has to open up a
point in his home board, thus providing a point of rentry. It should
be noted, the he doesn't loses his turn, as he still retains the
ability to double his opponent before any of his opponents rolls,
assuming the cube is centered or on his side.
A player is compelled to take his complete move if there is any
way for him to do so. If he can take either of the numbers but not
both, he must take the higher number if possable, the lower if not.
[Another way of saying this...]
- If both parts of the roll can be played legally, then this must be
done. Note that you may play the roll in such a way as to move fewer
pips than the larger die indicates by playing the smaller die first ---
this is common in bearoff situations, and legal as long as each part of
the roll is played legally at the moment you play it.
- If only one part of the roll can be played legally, then you must play
the higher die if possible; if not, play the lower die.
--kw
Once a player has brought all his men into his home board, he can
commence bearing off. Men borne off the board are not re-entered into
play. The player who bears off all his men first is the winner. A
player may not bear off men while he has a man on the bar, or outside
his home board. Thus if, in the process of bearing off, a player
leaves a blot and it is hit by his opponent, he must first re-enter
the man in his opponents home board, and bring it round the board
into his own home board before he can continue the bearing off
process.
In bearing off, you remove men from the points corresponding to
the numbers on the dice cast. However, you are not compelled to
remove a man. You may, if you can, move a man inside your home board
a number of spaces equivalent to the number of a die.
If you roll a number higher than the highest point on which you
have a man, you may apply that number to your highest occupied
point. Thus, if you roll 6-3 and your 6-point has already been
cleared but you have men on your 5-point, you may use your 6 to
remove a man from your 5-point.
In some cases it may be advantagous to play the smaller die first
before applying the higher die to your highest point (See Compulsory
Move). For example, suppose you have one checker on your 5 point,
and two checkers on your 2 point. Your opponent has a checker on
the ace (one point) and on the bar. You roll 6-3. You may play the
3 to the 2 point then the 6 to bear a checker off the 2 point
leaving your opponent no shots (no blots for the opponent to hit).
The alternative, using the 6-3 to bear checkers off both the 5 and 2
points, would leave your opponent 20 out of 36 ways to hit your
remaining blot.
If you bear off all 15 of your men before your opponent has borne
off a single man, you win a gammon, or double game.
If you bear off all 15 of your men before your opponent has borne
off a single man, and he still has one or more men in your home board
or on the bar, you win a backgammon, or a triple game.
It is customary to cast your dice in your right-hand board. Both
dice must come to rest completely flat in that board. If one die
crosses the bar into the other table, or jumps off the board, or does
not come to rest flat, or ends up resting on one of the men, the dice
are ``cocked'' and the whole throw, using both dice, must be retaken.
The introduction of the doubling cube into the game is largely
responsible for the leap in popularity of modern backgammon.
Each face of the doubling cube bears a number to record
progressive doubles and redoubles, starting with 2 and going on to 4,
8, 16, 32 &; 64. At the commencement of play, the doubling cube rests
on the bar, between the two players, or at the side of the board. At
any point during the game, a player who thinks he is sufficiently
ahead may, when it is his turn to play and before he casts his dice,
propose to double the stake by turning the cube to 2. His opponent
may decline to accept the double, in which case he forfeits the game
and loses 1 unit, or accept the double, in which case the game
continues with the stake at 2 units. The player who accepts the
double now ``owns'' the cube---which means that he has the option t
redouble at any point during the rest of the game, but his opponent
(the original doubler) may not. If, at a later stage he exercises
this option, his opponent is now faced with a similar choice. He may
either decline the redouble and so lose 2 units, or accept and play
for 4, and he now ``owns'' the cube. A player may double when he is on
the bar even if his opponent has a closed board and he cannot enter.
Though he does not roll the dice, for he cannot make a move, he still
has the right to double. Note that gammon doubles or backgammon
triples the stake of the cube.
From the FIBS help screens:
If you are playing an n-point match and your opponent is ahead
of you and he gets to n-1 points you are not allowed to use
the doubling cube in the next game to come
EXAMPLE:
5 point match
score
game # You opponent
1 0 3
2 0 4
3 1 4 (you were not allowed to double in this game)
4 3 4 (you were allowed to double again)
... ... ...
The Crawford rule is universally used in backgammon match play.
The Jacoby rule is used in money games. It states, that a gammon
or backgammon may not be scored as such unless the cube has been
passed and accepted. The purpose is to speed up play by eliminating
long undoubled games.
The Jacoby rule is never used in match play.
This rule applies to match games and states that in post-Crawford games
the trailer can only double after both sides have played two rolls. It
makes the free drop more valuable to the leader but generally just
confuses the issue.
Unlike the Crawford rule, the Holland rule has not proved popular,
and is rarely used today.
In money play, if player A doubles, and player B believes that he is
a favorite holding the cube, he may turn the cube an extra notch as he
takes, and keep the cube on his own side. For example, if A makes an
initial double to 2, B may, instead of taking the double and holding a
2 cube, say ``beaver'', turn the cube an extra notch to 4, and continue
the game holding a 4 cube.
If A believes that B's beaver was in error, some play that he may then
``raccoon'', turning the cube yet another notch (to 8 in the example). Cube
ownership remains with B. B may then if he wishes turn the cube yet
another notch, saying ``aardvark'', or ``otter'' or whatever silly animal
name he prefers (the correct animal is a matter of controversy), and so
forth.
Beavers and the rest of the animals may be played or not in money
play, as the players wish.
Beavers and other animals are never used in match play.
-- Andy Latto
It should be noted that the original cube turner can drop a beaver.
For example, suppose I miscount a bearoff and double, you accept and
say you want to beaver. I realize something is wrong and recount.
If I am horribly behind, I can drop the beaver, paying you the value
on the cube before you beavered.
-michael j zehr
A Chouette is a social backgammon variant for more than 2 players.
One player is ``the box'', and plays against all other players
on a single board. One other player is the captain, and rolls the
dice and makes the plays for the team that opposes the box. If the
box wins, the captain goes to the back of the line, and the next player
becomes captain. If the captain wins, the box goes to the back of the
line, and the captain becomes the new box.
Customs vary as to the rights of the captain's partners: In some Chouettes,
they may consult freely as to the way rolls should be played. In
others, consultation is prohibited. A compromise, where consultation
is allowed only after the cube has been turned, is popular.
Originally, Chouettes were played with a single cube. The only
decisions that players other than the captain were allowed to make
independently concerned takes: If the box doubled, each player on the
team could take or drop independently. Today, multiple-cube Chouettes
are more popular; each player on the team has his own cube, and all
doubling, dropping, and taking decisions are made independently by all
players.
-- Andy Latto