defense after any change of possession, the ball should be cleared past the 3 point line (or at times just out of the key) in order to win, a player must make exactly 21 points; if he goes over then he restarts back at either 11, 13 or 15 points, depending on the rules in use whoever wins the game starts with the ball at the beginning of the next game only serious fouls are called (commonly referred to as "No blood, No foul") other typical basketball rules, such as out-of-bounds, are also frequently ignored in the game "21"; this is to avoid confusion on possession of the ball Common additional rules include: if a missed shot is tipped in to the basket by another player without their feet touching the ground, then the shooter's score reverts to 0 (or 13 if their score was over 13); this rule may not apply on free-throws. (This is referred to as playing with tips) if a player who has 13 points misses their next shot, regardless of whether it is a free-throw, then their points revert to 0. (This is referred to as poison points) whoever wins the game must shoot a three-pointer in order to start with the ball at the beginning of the next game; if he makes it, he gets the three points, but doesn't have to take free-throws, and starts with the ball. players with less than 13 points at the end of a game keep their points into the next game using the (handicap system) for when there is a wide variation in skill amongst the players. "21" is considered a very challenging game, especially because the offensive player must possibly go up against several defenders at the same time. For this reason, it is exceedingly difficult to "drive to the hole" and make lay-ups in "21." Therefore, and also because of the emphasis on free-throws, "21" is very much a shooter's game, and because a successful shot means you keep the ball, it is possible for there to be come-backs when a player recovers from a large deficit by not missing any shots (this can also result in failure when they miss their final free-throw at 20 points and revert to 13 or 15). "21" is popular because it allows an odd number of people to play, unlike regular basketball or other variants. H-O-R-S-E The game