The Rules
While all the general rules of pool apply to nine ball, there are a few particular rules that you will have to learn. The rules of nine ball are fairly simple; it's learning the strategy that will take a little time and help you become a good player. It may help you to refresh your memory on some of the general pool rules as well as some of the eight-ball rules to learn the rules of nine ball. There are some subtle differences and special nuances in the rules, but those mainly have to do with the fouls.
After the Break
If you pocket one or more balls on the break shot, you get to keep shooting. You keep shooting until you either foul, don't pocket a ball, or win the game. If you don't pocket a ball or foul, your opponent takes his or her turn at the table (with ball-in-hand if you fouled) and keeps playing until he or she fouls, misses, or wins. The game continues until someone legally pockets the 9 ball.
Push-Out Shot
The player who shoots first after the break (either you or your opponent, depending on who pockets a ball first) has the option of “pushing out.” A push out allows a player to get the cue ball into a better location on the table to avoid any bad luck they may have gotten as a result of the break. This is where all the rules change.
The two side balls in the rack (the ones on either side of the center 9 ball) are often referred to as “wing” balls. Shots that are difficult to make are referred to as “testers” inpool-speak.
Let's say that after the break, the first shot available to you is next to impossible. In this case, you are allowed to hit the cue ball wherever you want to — you don't even have to contact a ball or cushion; you just move the cue ball to a position that will work better for you. But beware: At this point, your opponent has the option to play the shot. He or she can accept it or reject it. If your opponent rejects it, you have to play it. If your opponent accepts it, you have to watch as he or she takes over the table. If you made a lot of balls on your break shot, this could mean the win for your opponent. But if you get the cue ball into a position that you think you can make, or play a strategic safety that your opponent may not see, you'll get to hold on to your turn and maybe even win the game yourself.
Rules that apply to a push out:
If you pocket a ball on a push out, the ball doesn't count and remains pocketed (unless it's the 9 ball).
You cannot win the game on a push out.
If you scratch on your break shot, you lose your turn, and your opponent does not have the option of playing a push out.
You must announce that you will “push out” before you shoot.
Fouls
Since the rules are so simple, it is important to know how not to foul. Remember in eight ball how an illegally pocketed ball stays in the pocket? That's true in nine ball as well. However, an illegally pocketed 9 ball is spotted on the foot spot. The next player then takes cue-ball-in-hand (unless you pocketed the 9 ball in a push out) and places it anywhere on the table. If you foul three consecutive times, you will lose the game! However, you must inform your opponent that he or she is on two fouls, or the third one doesn't constitute loss of game. Now,

