Backgammon
2 of the 7 encyclopedias on this shelf carry an entry for Backgammon. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a game played with dice, men, and a board. The board is marked off into four quarters or tables, each containing six points, corresponding to the six spots of the dice. The first or entering table may be at either player's left hand, the home table at either player's right. The points are counted from left to right in that half of the board containing the entering table, from right to left in the other half, although the men of both players move in the same direction throughout the game. Thus the last point a man may reach is point one of the home table. The players sit opposite each other, one having fifteen black men, the other as many white. The players take turns in throwing the dice. The player places men on the points, or moves them forward from point to point, according to the spots thrown with the dice. If, for instance, he throws a one and a four, he places a man on the first point and another on the fourth point of the first quarter. As soon as his men are all on, he begins to move them forward. A throw of a two and a three, for instance, authorizes a player to move one man two points forward and another three. If doubles are thrown, the player doubles his play. That is, if he throws two fours, he has the right to play fours. He may then play the "opposites" or four threes. In addition he has the privilege of a second throw. Under the rules of the game a man occupying a point alone may be removed from the board at any time that the opponent is authorized to occupy the position, in which case it must make the journey anew. A man that has been thrown off by one's opponent must be replaced before any moves can be taken. A point defended by two or more men may not be occupied by one's adversary. In the last quarter the men may be removed, or "thrown off" instead of moved forward. For instance, if five and four be thrown, a man may be thrown from point five and one from point four. If the proper point contains no men, and none stand on a higher point, the player may "throw off" from the next lower point that contains men. He wins the game whose men make the journey from the first quarter or table to the last and are thrown off before his opponent's. The game is largely one of chance, but skill may be acquired in blocking the progress of one's opponent, while still advancing one's own men. The origin of the name is unknown. The probabilities are, however, that the word is of Anglo-Saxon origin, meaning "back game," or a game in which the men are likely to be sent back. The game originated, it is thought, in the tenth century. Backgammon is mentioned by Chaucer, and has always been regarded as a reputable game. 2026 Editor's Note: Backgammon is among the oldest games humanity plays — versions go back nearly 5,000 years to Mesopotamia. It also holds a place in AI history: in the 1990s a self-teac hing neural network, TD-Gammon, reached world-class play and overturned strategies human masters had believed for decades, an early sign of what machine learning could do. (Ed: BR 2026-07-04)
Collier's New Encyclopedia (1921)
a game of chance and calculation. It is played by two persons, with two boxes, and two dice, upon a quadrangular table, or board, on which are figured 24 points, or flèches, of two colors, placed alte alternately. The board is divided into four compartments, two inner and two outer ones, each containing six of the 24 points (alternate colors). The players are each furnished with 15 men, or counters, black and white. These are arranged upon the board in the following manner: To play into the left hand table, two of your men are placed upon the ace-point of your opponent's inner table, five upon the sixth point in his outer table, three upon the cinque-point in your own outer table, and five upon the sixth point in your own inner table. The adversary's men are to be placed in corresponding order, in a position directly opposite. The game consists in moving your men from point to point, so as to bring them around into your own inner table (i, e., that on your left hand), and then moving or bearing them off the board. The player who first clears off his men wins. The moves of the men are determined by the throws of the dice, according to the directions for playing. It will there be seen that the most advantageous throw at the outset is that of aces, as it blocks the bar, or sixth point in your outer table, and secures the cinque-point in your inner table, so that your adversary's two men cannot move if he throw either quarter, cinque, or size. This throw is frequently contested by inferior players, at the commencement of the game, by way of odds. As the grand object of the game consists in bringing around your men into your own inner table, all throws that contribute toward that end, and prevent your adversary from doing the same, are advantageous, and vice versa. Each party plays into one of the tables on his own side; thus, if black plays into his left hand table, white plays into his right (i. e., that which is exactly opposite) and vice versa, their men advancing in contraposition to each other. For right of first play each party throws a single die; he who throws the highest number wins, and may, if he chooses, adopt and play the joint number of the preliminary throw.