Ten-ball is preferred over nine-ball by some professionals as a more challenging discipline than nine-ball, because it is slightly harder to any balls on the with the more crowded , the initial shooter cannot instantly win the game by pocketing the 10 on the break, all shots must be , and performing a string of on successive racks is statistically more difficult to achieve.
Although the game has existed for a long time, its popularity has risen in recent years as a result of concerns that nine-ball has suffered as a result of flaws in its fundamental structure (particularly the ease with which players can often make balls from the break). The World Pool-Billiard Association (WPA) World Standardized Rules for 10-ball are very similar to those for nine-ball, but with key changes to ensure the difficulty of the game and its marketability as an alternative to nine-ball.
The 10 balls are racked in a triangle as in the game of eight-ball (but with 10 instead of 15 object balls, forming a tetractys), with the 1 ball positioned at the apex of the rack, the 2 and 3 balls on the bottom corners of the triangle (non-specific), the 10 ball positioned in the middle of the rack, and the other balls placed randomly throughout, with the apex ball on the foot spot.
This section needs expansion with: a summary of the WPA rules. You can help by adding to it. (November 2007)
Most of the same rules apply as in nine-ball. This means that in order to establish a legal hit, the cue ball must contact the lowest numbered ball first, and subsequently at least one ball must hit any rail or be pocketed, without the cue ball being pocketed. In 10-ball, shots have to be , which means that the player must call a ball and the pocket in which to make the ball, usually by pointing to a pocket with his finger or cue, and stating the number of the ball he intends to make in that pocket (not necessarily the lowest-numbered ball on the table, e.g. if a combination or carom shot is being attempted). If the 10 ball is pocketed on the break, it will be spotted and the player will continue his inning (previously a 10 ball made on the break resulted in a win).
Under WPA World Standardized Rules, it is a game, in which , or shots that go in an unintended pocket (usually by simple random chance) do not count; that is, unlike in nine-ball, the ball to be pocketed and the pocket must be specified. If a player pockets only the wrong ball, or pockets the nominated ball in the wrong pocket, the ball stays down. The opponent then has the choice of taking the shot, or handing it back. The exception is the 10 ball, which gets respotted on the . This format is considered controversial among some of the game's elite, as many pros are experts at playing multi-way shots where they may be attempting to pocket more than one ball on a given shot. Nonetheless, the rule has been adopted for professional competitions.