Nine-Ball is a variation of Pocket Billiards. The game may be played in social and recreational settings by any number of players. Nine ball is a relatively fast-paced game and is rarely played by the rack. The goal of the game is to pocket the nine ball in a legal manner as per the predefined rules of the games.

The game is played on a pocket billiard table with six pockets and with ten balls.The cue ball is struck to hit one or more of the other nine balls, each of which is distinctly colored and numbered "1" through "9". In nine ball, on all shots, a player must cause the cue ball to contact the lowest numerical ball on the table first before the cue ball strikes any other ball, otherwise it is considered as a foul.

One person is choosen to break first (called The Break), & for that the coin is tossed up to decide the first player. If the assigned player fails to make a legal break, the rack is re-arranged and the opposite player may demand the break.

If the player shooting the resulting shot fouled, the other player would have "ball in hand". But very soon, the "push Out" variant was ruled out of the Game and this change profoundly affected the way the game was played. Then the new Push out Rule was added and was named as "Texas Express" rules,because of the supposed state of origin and the speeding up of the game.Today, Texas Express push out rules dominate the way nine ball is played and is the variant incorporated into the official rules maintained
For much of its history nine ball rules allowed participants to "push out" multiple times during a game, meaning any player could call a "push out", and then hit the cue ball to any area on the table without being penalized by normal foul rules. This manner of playing nine ball is considered "two-foul." However, once a push out was called and executed, the incoming player had the right to shoot or give the inning back to the opponent.