The game of Pah Tum originated in Mesopotamia and Assyria and is at least 3,800 years old making it one of the oldest board games in history. A board made of ivory was discovered in the tomb of the Egyptian king Reny-Seneb, of the 12th dynasty, and dated at around 1800 BC.
The game of Pah Tum is played by two players on a 7x7 board shown in Figure 1. Each player has 24 pieces, one black and the other white. Before the game starts the players decide to randomly close off an odd number of squares (or black holes) on the board from play. No pieces can be placed on these black holes shown as an X in Figure 1. The players decide the number of black holes, and then decide randomly which squares on the board will be the black holes. Usually, the number of black holes will be either 3, 5, 7, 9, 11 or 13. This leaves an even number of squares available for play.
The players take turns to place their pieces on any available vacant square on the board. The players attempt to form the longest possible orthogonal (not diagonal) straight lines on the board. Points are scored for getting three or more pieces in the line. The number of points scored is:
- 3-in-a-row: 3 points
- 4-in-a-row: 10 points
- 5-in-a-row: 25 points
- 6-in-a-row: 56 points
- 7-in-a-row: 119 points
In Figure 1 white has 1 line of 4 pieces and 1 line of 2 pieces, with a score of 10 + 0 = 10 points, and black has 2 lines of 3 pieces and 1 line of 2 pieces, with a score of 3 + 3 + 0 = 6 points.
The game is finished when there are no vacant squares on the board. The player with higher amount of points is the winner. If both players have the same points, the game is a draw.
The random black holes help reduce the first player advantage. To further balance the game, the pie rule is used in which the second player has the option of swapping sides after the first move.