Twenty-one, also called 21, American, cutthroat, hustle, roughhouse, rough,or scramble is a popular variation of street basketball. The game is played with any number of players on a half court, but typically when not enough players are available to at least play three-on-three. Twenty-one is an individual game that does not utilize team play. In some settings, it is considered a brutal game, as fouling is legal and thus some games can become violent and full-contact. However, the game's basic rules can be enjoyed by any demographic, as most games are non-violent.
The rules and game play are often different regionally locally – even by specific court.
Basic rules are as follow:
Typically play begins with one player shooting the ball from a significant distance. This shot must hit the rim, but can not go through the basket. If either of these violations occur, the ball must be re-shot. Once the ball is legally shot, all players then fight over the rebound. This is meant to mimic the "tip-off" of a standard game. Once the ball is in play, there are technically no rules, but due to peer pressure most players abide by all rules with the exception of out of bounds violations and personal fouls.
Shots made after the ball is live count two points for a player's score (or 3 points if a 3-pointer is made). After each made field goal, the player making the field goal shoots up to three free throws in a row, until he misses. All free throws count as one point towards a player's count. If three free throws are made in a row, the free throw shooter is handed the ball back at the top of the key and play is live again.
The game is won by the player who accumulates exactly 21 points. If a player goes over 21 points, his score is reduced to 11 points. To avoid going over 21, players may choose to miss a free throw intentionally. In this instance, a free throw must hit the rim to be legal. If it does not, the player must shoot again. Sometimes this results in the player accidentally making the shot.
Common additional rules include:
- Regional variations may include: A field goal counting for 2 points and the 3-point shot (which is only two in street basketball) counting for 1 point, Going back to zero at 11, and/or having to win by a certain number of points
- Allowing the starting shot to score points for the shooter if it goes in
- Inverting scoring values such that a field goal is worth 1 and a free throw worth 2
- Forcing a player to take a fourth free throw and intentionally miss if he has made all 3 free throws, instead of just returning the ball to him
- A player can attempt a 3-pointer instead of attempting three free throws
- Variations on what a score is reset to if 21 is exceeded (7, 10, 11, 13, and 15 are common)
- "Tips" or "Taps" : With these rules, if a player jumps up, gets a rebound in the air and makes a shot before touching the ground, the player who initially shot the ball is said to have been "tipped." or "tapped", and their score is reset to zero (or sometimes to 11 if their score is 12 or greater). In some variations, the tipper is awarded bonus points (usually 3-5), the one being tipped is penalized points, or a combination of both ("stealing points"). In some games, if a player gets tipped 3 times, or if their score is already zero, they are out of the game. In another variation, if a player is tapped using only one hand, they are immediately eliminated.
- If a player who has 11 points misses the next shot, regardless of whether it is a free throw, then that player's points revert to 0. This is referred to as "poison points".
- Players with fewer than 11 points at the end of a game keep their points into the next game (a sort of handicapping system for when there is a wide variation in skill between the players).
- After exactly 21 points are reached, the player must make a final 3 pointer.
Formal use 
Twenty-one is frequently used in physical education classes and by basketball team coaches as skill development. Because only one player is on offense at any given time against several defenders, quickness and shooting skills are essential to successful play.
See also 
||This article needs additional citations for verification. (September 2008)|
- Eric Shanburn (2008), Basketball and Baseball Games: For the Driveway, Field Or the Alleyway, AuthorHouse, ISBN 978-1-4343-8912-1, retrieved 2010-06-29
- Phelps, Richard; John Walters, Tim Bourret (2000). Basketball For Dummies 2nd Edition. New York, NY: Hungry Minds, Inc. p. 206. ISBN 0-7645-5248-1.
- How to Coach and Play Basketball[clarification needed]]]
- Journal of Physical Education and Recreation[clarification needed]]]