The 17 dots around the pool table are equally positioned from each other. There are three dots between each pocket except for the center diamond spot in one of the short rails; this is typically replaced by the name of the manufacturer of the pool table. Each dot is designed to act as an angle marker to guide players in making bank shots; for example, a typical straight shot aimed at a dot will bounce off at a right angle.
Pool experts use all 17 dots, the imaginary 18th dot plus each of the pockets as a geometric way to divide the table. The distance between the dots acts as an imaginary ruler. David Alciatore, author of The Illustrated Principles of Pool and Billiards, suggests using a corner pocket as point “zero” and then to count up between diamonds. Each diamond would be in tens: the first dot from the corner pocket would be 10, the next 20, and so on. This effectively divides the pool table into fractions to make precise shots. This mental imaging skill is particularly important; most tournaments do not allow players to use any tool to measure the table during a game.