Classic Games for OS/2 Warp/Classic Games for OS2 Warp (1995)(IBM).iso/tdgammon/tdgammon.hlp

OS/2 Help File | 1995-05-26 | 31.3 KB | 809 lines

ΓòÉΓòÉΓòÉ 1. General help ΓòÉΓòÉΓòÉ

Backgammon is a game of both skill and luck in which two player move their
"men" in an obstacle race around the board, trying to get their men off the
board before their opponent does.

OS/2 TD-Gammon lets you play against one of the strongest backgammon players in
the world - an artificially intelligent player called TD-Gammon. At its easiest
skill levels, OS/2 TD-Gammon will help you learn the ancient and intriguing
game of backgammon as if you were playing against a novice at the game. At its
highest skill levels, only a few of the best backgammon players in the world
stand a chance of beating TD-Gammon consistently.

Are you up to the challenge?

Further information is available on:

o What is TD-Gammon?
o Starting the OS/2 TD-Gammon program
o How to play OS/2 TD-Gammon
o Setting the skill level
o Starting a new game
o Exiting the program


o Rules of backgammon


ΓòÉΓòÉΓòÉ 1.1. What is TD-Gammon? ΓòÉΓòÉΓòÉ

TD-Gammon is a world-famous computer program that has revolutionized the game
of backgammon.  Based on breakthrough research in Artificial Neural Network
technology, TD-Gammon actually taught itself to play backgammon, starting from
scratch. It learned to play so well that it is now one of the very best
backgammon players in the world.

OS/2 TD-Gammon is a special edition of TD-Gammon that uses the facilities of
OS/2 to bring this world-class game to you.  It was developed by Gerald Tesauro
and Keith Weiner at the world-famous IBM Thomas J. Watson Research Center,
where it started as an experiment in artificial intelligence.

Tesauro started with an artificial neural network, a computer simulation
inspired by the human brain, that knew only the basic rules of backgammon: what
moves were legal, when the game is over, how to keep score, and so on.

He then put this neural network through a "training procedure" in which it
played many games against itself, and learned from the outcome of each game.
At the start of training, the network only knew how to choose randomly from the
list of legal moves. Over the course of many thousands of training games, the
network gradually improved its playing ability. After millions of games of
experience, the neural network is now playing at the level of today's top human
experts.

Now you can play against this amazing computer opponent. Good luck!

Further information is available on:

o For further reading


ΓòÉΓòÉΓòÉ 1.1.1. For further reading ΓòÉΓòÉΓòÉ

There are many good books available on backgammon strategy. Two-time World
Backgammon Champion Bill Robertie wrote a particularly fine book for beginners:

Bill Robertie, "Backgammon for Winners," Cardoza Publishing, ISBN:
0-940685-42-6.

Bill Robertie has also written an article describing his experience in playing
against TD-Gammon:

B. Robertie, "Carbon versus Silicon: matching wits with TD-Gammon," Inside
Backgammon, Volume 2, No. 2, pp. 14-22 (1992). Inside Backgammon is a
newsletter which can be obtained from The Gammon Press, P. O. Box 294,
Arlington, MA 02174.

A detailed technical article by Dr. Gerald Tesauro, the IBM Research scientist
who developed the neural network used by TD-Gammon, describes the techniques it
uses:

G. Tesauro, "Temporal Difference Learning and TD-Gammon," Communications of the
ACM, Volume 38, No. 3, pp. 58-68 (March 1995).


ΓòÉΓòÉΓòÉ 1.2. Starting the OS/2 TD-Gammon program ΓòÉΓòÉΓòÉ

To start OS/2 TD-Gammon, double-click on its icon. Or, from an OS/2 session,
switch to the directory in which OS/2 TD-Gammon is installed and type TDGAMMON.
For instance, if OS/2 TD-Gammon is installed in C:\GAMES, you would type:

[C:\] CD \GAMES
[C:\GAMES] TDGAMMON

A window will appear containing a graphical display of a backgammon board set
up in the standard starting configuration.  TD-Gammon has the blue checkers,
and they move in the counter-clockwise direction.  You have the red checkers,
and they move in the clockwise direction. Your home board is the lower left
quadrant, and TD-Gammon's home board is the upper left quadrant.


ΓòÉΓòÉΓòÉ 1.3. How to play OS/2 TD-Gammon ΓòÉΓòÉΓòÉ

You play OS/2 TD-Gammon just like a regular backgammon game, except that you
use the mouse to move your pieces on the board. You move your pieces, and OS/2
TD-Gammon moves its pieces.

Further information is available on:

o The starting board position
o Rolling your dice
o Moving your checkers
o Offering a double
o Accepting or declining a double
o Keeping score


o Rules of backgammon


ΓòÉΓòÉΓòÉ 1.3.1. The starting board position ΓòÉΓòÉΓòÉ

At the start of each game, the doubling cube has a value of 1, and is
positioned in the middle, indicating that either player can double. Also at the
start of each game, the players each roll a single die to determine who goes
first.  The player who rolled the higher value gets to play the combination.
Your dice are red, and TD-Gammon's dice are blue.  If TD-Gammon gets to play
first, you will see it make a move, and then the dice will disappear.  If you
get to play first, you must make a legal move corresponding to the dice
combination that is shown.


ΓòÉΓòÉΓòÉ 1.3.2. Moving your checkers ΓòÉΓòÉΓòÉ

Checkers are moved by clicking on them with the left mouse button, dragging
them to the desired location, and then releasing the mouse button.  If you
attempt to move to an illegal location, the computer will beep and the checker
will reappear at the starting location.

If the computer has hit any of your checkers, they will be on the bar (the gray
strip in the middle of the board).  Checkers on the bar must re-enter the board
in the opponent's home quadrant before other checkers can be moved.

Once you have gotten all your checkers into your home quadrant, you can begin
bearing them off the board.  To bear checkers off, drag them to the gray border
area on the left edge of the board.  Checkers that have been borne off are
shown stacked up edgewise.

Before you have finished making a complete legal move, you are allowed to take
back some or all of the component moves that you have made so far.  To take
back a move, simply drag the checker back to the starting location.


ΓòÉΓòÉΓòÉ 1.3.3. Offering a double ΓòÉΓòÉΓòÉ

Each time that it is your turn to play, you can offer a double if the doubling
cube is in the middle or on your side of the board. To offer a double, click on
the doubling cube with the left mouse button.  If TD-Gammon accepts the double,
the cube will appear on TD-Gammon's side of the board, and will be set to twice
the previous value.  If TD-Gammon declines the double, a message will appear
indicating that you have won the game; congratulations!  Once you have doubled,
you cannot double again, as TD-Gammon has the exclusive right to make the next
double.

If you do not wish to offer a double, simply click anywhere on the board, and
your dice roll will appear.  Once your dice have been rolled, you cannot double
until your next turn.


ΓòÉΓòÉΓòÉ 1.3.4. Accepting or declining a double ΓòÉΓòÉΓòÉ

When TD-Gammon offers you a double, the cube will be turned to twice its
previous value, and will be moved toward your side of the board. To accept the
double, click on the doubling cube and drag it to the notched cube-holding
location on your side of the board.  To decline the double, click on the
doubling cube and drag it towards the middle of the board.


ΓòÉΓòÉΓòÉ 1.3.5. Keeping score ΓòÉΓòÉΓòÉ

OS/2 TD-Gammon keeps a running total of your score in the lower right-hand
corner of the window. You start out with a score of 0. When you win a game, the
number of points you win in that game is added to your score. If TD-Gammon wins
the game, the number of points it wins is subtracted from your score.

If you have won more points that TD-Gammon, your score will be positive
(greater than zero). If TD-Gammon has won more points, your score will be
negative (less than zero).

If you close TD-Gammon and open it again later, your score will be reset to 0.


ΓòÉΓòÉΓòÉ 1.4. Setting the skill level ΓòÉΓòÉΓòÉ

OS/2 TD-Gammon has five possible skill settings:

o Novice
o Beginner
o Intermediate
o Advanced
o Expert

To set the desired skill level, select the Options menu and a pull-down menu
will appear showing the five possible levels. Select the desired skill level
from this menu. The skill level can be reset at any time during a game, except
while the computer is moving or thinking.


ΓòÉΓòÉΓòÉ 1.5. Starting a new game ΓòÉΓòÉΓòÉ

To start a new game, select the New menu item from the File menu. The board
will be reset to the starting position.


ΓòÉΓòÉΓòÉ 1.6. Exiting the program ΓòÉΓòÉΓòÉ

To exit OS/2 TD-Gammon, double-click on the system icon in the OS/2 TD-Gammon
window, or select Exit from the File menu. When you exit the program, the
settings will be saved, but the current game will not be saved.


ΓòÉΓòÉΓòÉ 2. Rules of backgammon ΓòÉΓòÉΓòÉ

Backgammon is an obstacle race between two armies of 15 men each. Each man is
called a "checker", and moves around a track divided into 24 triangular-shaped
divisions known as "points". The goal of the game is to be the first player to
bring all of your men around the board and then off the board.

Further information is available on:

o The backgammon board
o Object of the game
o Starting a game
o Moving your men
o Doublets
o Making points
o Blots
o Closed board
o Compulsory moves
o Bearing off
o Gammon and backgammon
o The doubling cube


o Hints for successful play


ΓòÉΓòÉΓòÉ 2.1. The backgammon board ΓòÉΓòÉΓòÉ

The backgammon board is divided down the center by a partition, known as the
"bar" (See Diagram 1), into an outer and a home (or inner) board. The side
nearest you is your outer and home boards; 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 the other 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 your opponent's 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 the
6-point, three men on the 8-point, five men on the opponent's 12-point, and two
men on the opponents' 1-point.  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 >-----------------------+  |
                                               |  |
                                               |  |
 24 23 22 21 20 19       18 17 16 15 14 13     |  |
+------------------------------------------+   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
|                  |   |                   |   |  |   +----+
|   Home Board     |BAR|    Outer Board    |   |  |   | 64 |
|                  |   |                   |   |  |   +----+
| P  O  I  N  T  S |   |  .  .  .  .  .  . |   |  |  Doubling
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |    Cube
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
| .  .  .  .  .  . |   |  .  .  .  .  .  . |   |  |
+------------------------------------------+   |  |
  1  2  3  4  5  6        7  8  9 10 11 12     |  |
                                               |  |
   <-------------------------------------------+  |
                                                  |
O moves this direction >--------------------------+


            Diagram 1  (Numbered from X's point of view)

 24 23 22 21 20 19       18 17 16 15 14 13
+------------------------------------------+
| X  .  .  .  .  O |   |  .  O  .  .  .  X |
| X              O |   |     O           X |
|                O |   |     O           X |
|                O |   |                 X |
|                O |   |                 X |  +----+
|                  |BAR|                   |  | 64 |
|                X |   |                 O |  +----+
|                X |   |                 O |
|                X |   |     X           O |
| O              X |   |     X           O |
| O  .  .  .  .  X |   |  .  X  .  .  .  O |
+------------------------------------------+
  1  2  3  4  5  6        7  8  9 10 11 12

Diagram 2  (Numbered from X's point of view)


ΓòÉΓòÉΓòÉ 2.2. Object of the game ΓòÉΓòÉΓòÉ

The object of Backgammon is for each player to bring all of his or her men into
his or her home board, and then to bear them off the board. The first player to
get all of his or her men off the board is the winner.


ΓòÉΓòÉΓòÉ 2.3. Starting a game ΓòÉΓòÉΓòÉ

Each player casts one die. The player with the higher number makes the first
move, using the two numbers cast by the player's die and the 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.


ΓòÉΓòÉΓòÉ 2.4. Moving your men ΓòÉΓòÉΓòÉ

Each player's turn consists of the roll of two dice. The player then moves one
or more men in accordance with the numbers cast. If the dice roll is 4-2, the
player can 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.


ΓòÉΓòÉΓòÉ 2.5. Doublets ΓòÉΓòÉΓòÉ

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 the
dice roll is 3-3, the player 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 a turn.


ΓòÉΓòÉΓòÉ 2.6. Making points ΓòÉΓòÉΓòÉ

A player makes a point by positioning two or more of his or her men on it. The
player then "owns" that point, and the opponent can neither come to rest on
that point nor touch down on it when taking the combined total of the dice with
one man.


ΓòÉΓòÉΓòÉ 2.7. Blots ΓòÉΓòÉΓòÉ

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 board. A player
cannot make any move until all of that player's men that were on the bar have
been brought 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.


ΓòÉΓòÉΓòÉ 2.8. Closed board ΓòÉΓòÉΓòÉ

A player who has made all six points in his or her home board is said to have a
closed board. If the opponent has any men on the bar, the opponent will not be
able to re-enter since there is no vacant point in the adversary's home board.
Therefore, the opponent forfeits a turn, and continues to do so until such time
as the player has to open up a point in the home board, thus providing a point
of re-entry.


ΓòÉΓòÉΓòÉ 2.9. Compulsory moves ΓòÉΓòÉΓòÉ

A player is compelled to play both parts of the roll if there is any legal way
to do so.  Note that when bearing off, you can play the roll in such a way as
to move fewer spaces than the larger die indicates by playing the smaller die
first.  This is 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.


ΓòÉΓòÉΓòÉ 2.10. Bearing off ΓòÉΓòÉΓòÉ

Once a player has brought all of his or her men into the home board, the player
can commence bearing off. Men borne off the board are not re-entered into play.
The player who bears off all of his or her men first is the winner. A player
cannot bear off men while that player has a man on the bar, or outside the
player's home board. Thus if, in the process of bearing off, a player leaves a
blot and it is hit by the opponent, the player must first re-enter the man in
the opponent's home board, and bring it around the board into the player's own
home board before the player 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 can, if
possible, 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
can 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
can use your 6 to remove a man from your 5-point.

In some cases it might be advantageous 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 can 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.


ΓòÉΓòÉΓòÉ 2.11. Gammon and backgammon ΓòÉΓòÉΓòÉ

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. The number of points you win will be two
times the number of the doubling cube.

If you bear off all 15 of your men before your opponent has borne off a single
man, and your opponent still has one or more men in your home board or on the
bar, you win a backgammon, or a triple game. The number of points you win will
be three times the number on the doubling cube.


ΓòÉΓòÉΓòÉ 2.12. The doubling cube ΓòÉΓòÉΓòÉ

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 and 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 or she is sufficiently
ahead can, when it is the player's turn to play and before the dice are cast,
propose to double the stake by turning the cube to 2. The opponent can decline
to accept the double, in which case the opponent forfeits the game and loses 1
point, or accept the double, in which case the game continues with the stake at
2 points.

The player who accepts the double now "owns" the cube --- which means that the
accepting player has the option to redouble at any point during the rest of the
game, but the opponent (the original doubler) can not. If, at a later stage the
player exercises this option, the opponent is now faced with a similar choice.
The opponent can either decline the redouble and so lose 2 points, or accept
and play for 4, and he now "owns" the cube.

A player can double even with men on the bar even if the opponent has a closed
board and the player cannot enter. Though the player does not roll the dice,
since no move is possible, the player still has the right to double. Note that
a gammon doubles and a backgammon triples the stake of the cube.


ΓòÉΓòÉΓòÉ 3. Hints for successful play ΓòÉΓòÉΓòÉ

Backgammon is a game of both skill and luck. This section gives you a few hints
at the basic strategies and tactics that are important in winning. For a more
detailed discussion of strategy and tactics, see the references.

Further information is available on:

o Build blocking points
o Hit the opponent's blots
o Playing safe
o Taking chances


ΓòÉΓòÉΓòÉ 3.1. Build blocking points ΓòÉΓòÉΓòÉ

One of the primary objectives in backgammon is to block the escape of the
opponent's back men. Conversely, on the other side of the board, one of your
main objectives is to escape your opponent's blockade.  Blocking and escaping
are important, because a player cannot begin bearing off until all of his or
her men have been brought into his home board.  The best blocking points to
make are your 5 point, 7 point and 4 point.  So, for example, in the opening
position shown below in Diagram 3, you are X and have a roll of 3-1 to play.
You should play 8-5, 6-5, making your 5 point.

 24 23 22 21 20 19       18 17 16 15 14 13
+------------------------------------------+
| X  .  .  .  .  O |   |  .  O  .  .  .  X |
| X              O |   |     O           X |
|                O |   |     O           X |
|                O |   |                 X |
|                O |   |                 X |  +----+
|                  |BAR|                   |  | 64 |
|                X |   |                 O |  +----+
|                X |   |                 O |
|                X |   |     X           O |
| O              X |   |     X           O |
| O  .  .  .  .  X |   |  .  X  .  .  .  O |
+------------------------------------------+
  1  2  3  4  5  6        7  8  9 10 11 12

         Diagram 3 -- X to play 3-1


ΓòÉΓòÉΓòÉ 3.2. Hit the opponent's blots ΓòÉΓòÉΓòÉ

When you have an opportunity to hit the opponent, it is usually (but not
always) a good thing to do.  Hitting accomplishes two important objectives.
First, by sending the opponent blot to the bar, the opponent loses ground in
the race to get all of one's men home and off the board.  Second, the
effectiveness of the opponent's next roll is diminished, as the opponent has to
use half of the roll to re-enter the blot.  And sometimes the opponent loses an
entire turn if the opponent rolls a combination which does not permit the blot
to re-enter.  An illustration of the value of hitting is shown below in Diagram
4:

 24 23 22 21 20 19       18 17 16 15 14 13
+------------------------------------------+
| X  .  .  .  O  O |   |  O  O  .  .  .  X |
| X           O  O |   |  O              X |
|                O |   |                 X |
|                  |   |                   |
|                  |   |                   |  +----+
|                  |BAR|                   |  | 64 |
|                X |   |                 O |  +----+
|                X |   |     X           O |
|                X |   |     X           O |
| O              X |   |     X           O |
| O  .  .  .  .  X |   |  .  X  .  .  X  O |
+------------------------------------------+
  1  2  3  4  5  6        7  8  9 10 11 12

          Diagram 4 -- X to play 6-1

In this diagram, you are X and you have rolled 6-1.  In this position you have
the opportunity to build a good blocking point by playing either 13-7, 8-7, or
11-5, 6-5.  However, neither of these moves are as good as hitting the opponent
blot by playing 24-23, 23-17* (the asterisk denotes a hit).


ΓòÉΓòÉΓòÉ 3.3. Playing safe ΓòÉΓòÉΓòÉ

If hitting the opponent's blots is usually a good thing to do, then logically,
it follows that you should not give the opponent a lot of opportunities to hit
you.  It is often a good idea to minimize both the number of blots that you
have, as well as the chances of each blot being hit.  A good rule of thumb is
that blots located 7 spaces or more away from the opponent's men are much less
likely to be hit than those located 6 spaces away or less.

 24 23 22 21 20 19       18 17 16 15 14 13
+------------------------------------------+
| X  .  .  .  .  O |   |  .  O  .  .  O  X |
| X              O |   |     O           X |
|                O |   |     O           X |
|                O |   |                 X |
|                O |   |                   |  +----+
|                  |BAR|                   |  | 64 |
|                  |   |                   |  +----+
|                X |   |                 O |
|                X |   |     X           O |
|                X |   |     X           O |
| O  .  .  O  X  X |   |  .  X  .  .  X  O |
+------------------------------------------+
  1  2  3  4  5  6        7  8  9 10 11 12

        Diagram 5 -- X to play 5-2

Diagram 5 above shows a position where a safe play is required.  It is too wild
to hit O here with a move like 6-1*, 6-4*.  O would then be able to hit back
with 2-2 or with any roll containing a 1, 4, or 5, for a total of 28 out of 36
possible dice combinations.  Instead, you should play 8-3, 5-3.  This leaves
only one blot on the 11 point, located 7 spaces away from O's man on the 4
point, and 10 spaces away from O's man on the 1 point.  O only has 8 dice
combinations out of 36 that hit your blot (6-1, 5-2, 4-3 or 6-4).


ΓòÉΓòÉΓòÉ 3.4. Taking chances ΓòÉΓòÉΓòÉ

While it is good to play safe, one should not go overboard with minimizing
chances of being hit.  Especially in the early going, it is worth taking small
chances to try to improve your position.  An example is given in Diagram 6:

 24 23 22 21 20 19       18 17 16 15 14 13
+------------------------------------------+
| X  .  .  .  .  O |   |  .  O  .  .  .  X |
| X              O |   |     O           X |
|                O |   |     O           X |
|                O |   |     O           X |
|                O |   |                 X |  +----+
|                  |BAR|                   |  | 64 |
|                X |   |                   |  +----+
|                X |   |                 O |
|                X |   |     X           O |
|                X |   |     X           O |
| O  O  .  .  .  X |   |  .  X  .  .  .  O |
+------------------------------------------+
  1  2  3  4  5  6        7  8  9 10 11 12

         Diagram 6 -- X to play 5-2

In this position, you could play completely safe by moving 13-8, 8-6.  However,
this leaves you with a very inflexible position that is not likely to improve.
A much better alternative is 13-8, 13-11.  It is worth giving O a small chance
to hit you with a combination of 6-3, 5-4, or 6-4 (6 chances out of 36) in
order to give yourself a much better chance of building new points if you do
not get hit.


ΓòÉΓòÉΓòÉ 4. Bearing Off ΓòÉΓòÉΓòÉ

When all of your checkers are in your home board, you can bear off checkers by
dragging them to the lower "bin" on the left edge of the board. The player who
bears off all of his or her checkers first, wins.


ΓòÉΓòÉΓòÉ 5. Bar ΓòÉΓòÉΓòÉ

The bar is the central area of the board. Whenever a checker is hit (landed
upon by an opponent's checker), it is sent to the bar. Checkers that are on the
bar must be brought back into play before any other moves can be made by that
player.


ΓòÉΓòÉΓòÉ 6. Doubling ΓòÉΓòÉΓòÉ

Before a player rolls the dice, that player can offer a double if that player
"owns" the doubling cube, or if neither player has doubled yet. To offer a
double to TD-Gammon, drag the doubling cube upwards towards your opponent.

When TD-Gammon offers a double to you, it will push the doubling cube downwards
towards you. To accept the double, drag the doubling cube downward. To decline
the double, drag the doubling cube upwards. If you accept the double, the
stakes of the game are doubled. If you decline the double, you forfeit the
game.


ΓòÉΓòÉΓòÉ 7. Dice ΓòÉΓòÉΓòÉ

When it is your turn, you can roll the dice by clicking on an open part of the
board with the left mouse button. If you want to double, remember to do so
before you roll the dice.


ΓòÉΓòÉΓòÉ 8. Help for New ΓòÉΓòÉΓòÉ

Select the New menu item from the File menu to end the current game and start a
new game.


ΓòÉΓòÉΓòÉ 9. Help for Exit ΓòÉΓòÉΓòÉ

Select the Exit menu item from the File menu to close OS/2 TD-Gammon. The
current settings will be saved, but the current game will not be saved.


ΓòÉΓòÉΓòÉ 10. Help for Settings ΓòÉΓòÉΓòÉ

Select the Settings menu item to open the Settings folder. The Settings folder
lets you set the skill level, the animation speed, and the colors of the
various parts of the TD-Gammon board.


ΓòÉΓòÉΓòÉ 11. Help for Novice ΓòÉΓòÉΓòÉ

Select the Novice level to tell TD-Gammon to play at the level of a novice
backgammon player. At this level, TD-Gammon is fairly easy to beat, even for a
player who is just learning backgammon. It knows the rules, and will generally
try to hit your blots when it can, but it does not know very much strategy.
This is the default skill level.


ΓòÉΓòÉΓòÉ 12. Help for Beginner ΓòÉΓòÉΓòÉ

Select the Beginner level to tell TD-Gammon to play at the level of a beginning
backgammon player. At this level, TD-Gammon will play like a player who knows a
few of the basic strategies of backgammon. It will make mistakes that would be
obvious to a more experienced backgammon player.


ΓòÉΓòÉΓòÉ 13. Help for Intermediate ΓòÉΓòÉΓòÉ

Select the Intermediate level to tell TD-Gammon to play at the level similar to
that of an intermediate backgammon tournament player. In some ways, it will be
a stronger player than a human who is an intermediate tournament player. In
other ways, it will be weaker.


ΓòÉΓòÉΓòÉ 14. Help for Advanced ΓòÉΓòÉΓòÉ

Select the Advanced level to tell TD-Gammon to play at the level similar to
that of an advanced backgammon tournament player. In some ways, it will be a
stronger player than a human who is an advanced tournament player. In other
ways, it will be weaker. At this level, most people will find TD-Gammon
difficult to beat consistently.

When playing at the advanced level, TD-Gammon spends more time thinking about
its moves than it does at lower levels. You might notice a delay when it is
thinking about doubling, and when it is thinking about its move, especially on
slower machines.


ΓòÉΓòÉΓòÉ 15. Help for Expert ΓòÉΓòÉΓòÉ

Select the Expert level to tell TD-Gammon to play at its highest level of
skill. At this level, even expert human players will have difficulty beating
TD-Gammon consistently.

When playing at the expert level, TD-Gammon spends more time thinking about its
moves than it does at lower levels. You will probably notice a delay when it is
thinking about doubling, and when it is thinking about its move, especially on
slower machines.


ΓòÉΓòÉΓòÉ 16. Help for Help index ΓòÉΓòÉΓòÉ

Select Help index from the Help menu for an index of the online help for OS/2
TD-Gammon.


ΓòÉΓòÉΓòÉ 17. Help for General help ΓòÉΓòÉΓòÉ

Select General help from the Help menu to see detailed information about OS/2
TD-Gammon.


ΓòÉΓòÉΓòÉ 18. Help for Using help ΓòÉΓòÉΓòÉ

Select Using help from the Help menu for information on the use of the online
help facility.


ΓòÉΓòÉΓòÉ 19. Help for Keys help ΓòÉΓòÉΓòÉ

Select Keys help from the Help menu to view a list of keys that can be used to
perform various actions from within OS/2 TD-Gammon.


ΓòÉΓòÉΓòÉ 20. Help for Rules ΓòÉΓòÉΓòÉ

Use Rules help from the Help menu to view a description of the basic rules of
backgammon.


ΓòÉΓòÉΓòÉ 21. Help for Hints ΓòÉΓòÉΓòÉ

Select Hints from the Help menu for some helpful hints on playing backgammon
well.


ΓòÉΓòÉΓòÉ 22. Help for Bearing off help ΓòÉΓòÉΓòÉ

Select Bearing off help from the Help menu for a description of bearing off
your pieces after your home board is filled.


ΓòÉΓòÉΓòÉ 23. Help for Bar help ΓòÉΓòÉΓòÉ

Select Bar help from the Help menu for a description of the "bar" on the
backgammon board.


ΓòÉΓòÉΓòÉ 24. Help for Doubling cube help ΓòÉΓòÉΓòÉ

Select Doubling cube help from the Help menu for a description of the doubling
cube.


ΓòÉΓòÉΓòÉ 25. Help for Dice help ΓòÉΓòÉΓòÉ

Select Dice help from the Help menu for information on how to use the dice in
OS/2 TD-Gammon.


ΓòÉΓòÉΓòÉ 26. Help for Product information ΓòÉΓòÉΓòÉ

Select Product information from the Help menu for information about OS/2
TD-Gammon, such as the version number and copyright information.


ΓòÉΓòÉΓòÉ 27. Keys help ΓòÉΓòÉΓòÉ

You can get help on any object on the backgammon board by clicking on that
object with the right mouse button. To get help on the doubling cube, for
instance, click on the doubling cube with the right mouse button.

The following keys can be used in OS/2 TD-Gammon instead of using the mouse to
click on menu items.

Alt+F     Display the File menu

Alt+O     Display the Options menu

Alt+H     Display the Help menu

F1        Context-sensitive help