In basketball, a personal foul is a breach of the rules that concerns illegal personal contact with an opponent. It is the most common type of foul in basketball. A player fouls out on reaching a limit on personal fouls for the game and is disqualified from participation in the remainder of the game. Players routinely initiate illegal contact to purposely affect the play, hoping it is seen as too minor to be ruled a foul. The threshold is subjective and varies among officials and from game to game. Most contact fouls are not regarded as unsportsmanlike. However, excessive or unjustified contact is penalized more severely. The NBA refers to these as flagrant fouls; other rulebooks call them unsportsmanlike or disqualifying fouls. History Basketball has always had the concept of fouls. In 1891, James Naismith's original 13 rules defined a foul as: running with the ball, holding the ball with the arms or body, striking the ball with the fist, shouldering, holding, pushing, striking or tripping in any way of an opponent. Only the fourth definition remains. Running with the ball and striking it with the fist are now violations. Holding the ball with the arms or body is now rare but legal. Originally, on a player's second foul, the player would be removed without substitution until the next successful goal (similar to a penalty in ice hockey). Before long, free throws were introduced, originally worth three points each, then one. Originally, any team member was allowed to shoot free throws. In 1924, the rules were changed so that the fouled player shot the free throws. The victim of a contact foul used to be given three attempts at a free throw, and the offense retained possession of the basketball. Now, a player fouled in the act of shooting gets from one to three shots and the other team tends to get possession afterwards (see Penalties below). Principles Personal contact does not necessarily constitute a personal foul, unless it gives a player an advantage or puts the opponent at a disadvantage. Cylinder In FIBA, the cylinder principle gives each player exclusive rights within an imaginary cylinder defined: in the front by the palms of the hands, when the arms are bent at the elbows so that the forearms and hands are raised, but no farther in front than the feet, in the rear by the buttocks, at the sides by