Basketball is a team sport in which two teams, most commonly of five players each, opposing one another on a rectangular court, compete with the primary objective of shooting a basketball (approximately 9.4 inches (24 cm) in diameter) through the defender's hoop (a basket 18 inches (46 cm) in diameter mounted 10 feet (3.048 m) high to a backboard at each end of the court) while preventing the opposing team from shooting through their own hoop. A field goal is worth two points, unless made from behind the three-point line, when it is worth three. After a foul, timed play stops and the player fouled or designated to shoot a technical foul is given one or more one-point free throws. The team with the most points at the end of the game wins, but if regulation play expires with the score tied, an additional period of play (overtime) is mandated.|
The five players on each side at a time fall into five playing positions: the tallest player is usually the center, the tallest and strongest is the power forward, a slightly shorter but more agile big man is the small forward, and the shortest players or the best ball handlers are the shooting guard and the point guard, who implements the coach's game plan by managing the execution of offensive and defensive plays (player positioning). Informally, players may play three-on-three, two-on-two, and one-on-one.
The peach baskets were used until 1906 when they were finally replaced by metal hoops with backboards. A further change was soon made, so the ball merely passed through. Whenever a person got the ball in the basket, his team would gain a point. Whichever team got the most points won the game. The baskets were originally nailed to the mezzanine balcony of the playing court, but this proved impractical when spectators in the balcony began to interfere with shots. The backboard was introduced to prevent this interference; it had the additional effect of allowing rebound shots. Naismith's handwritten diaries, discovered by his granddaughter in early 2006, indicate that he was nervous about the new game he had invented, which incorporated rules from a children's game called duck on a rock, as many had failed before it.
James Naismith was instrumental in establishing college basketball. His colleague C.O. Beamis fielded the first college basketball team just a year after the Springfield YMCA game at the suburban Pittsburgh Geneva College. Naismith himself later coached at the University of Kansas for six years, before handing the reins to renowned coach Forrest "Phog" Allen. Naismith's disciple Amos Alonzo Stagg brought basketball to the University of Chicago, while Adolph Rupp, a student of Naismith's at Kansas, enjoyed great success as coach at the University of Kentucky. On February 9, 1895, the first intercollegiate 5-on-5 game was played at Hamline University between Hamline and the School of Agriculture, which was affiliated with the University of Minnesota. The School of Agriculture won in a 9–3 game.
Today virtually every high school in the United States fields a basketball team in varsity competition. Basketball's popularity remains high, both in rural areas where they carry the identification of the entire community, as well as at some larger schools known for their basketball teams where many players go on to participate at higher levels of competition after graduation. In the 2016–17 season, 980,673 boys and girls represented their schools in interscholastic basketball competition, according to the National Federation of State High School Associations. The states of Illinois, Indiana and Kentucky are particularly well known for their residents' devotion to high school basketball, commonly called Hoosier Hysteria in Indiana; the critically acclaimed film Hoosiers shows high school basketball's depth of meaning to these communities.
The NBA has featured many famous players, including George Mikan, the first dominating "big man"; ball-handling wizard Bob Cousy and defensive genius Bill Russell of the Boston Celtics; charismatic center Wilt Chamberlain, who originally played for the barnstorming Harlem Globetrotters; all-around stars Oscar Robertson and Jerry West; more recent big men Kareem Abdul-Jabbar, Shaquille O'Neal, Hakeem Olajuwon and Karl Malone; playmakers John Stockton, Isiah Thomas and Steve Nash; crowd-pleasing forwards Julius Erving and Charles Barkley; European stars Dirk Nowitzki, Pau Gasol and Tony Parker; more recent superstars LeBron James, Allen Iverson and Kobe Bryant; and the three players who many credit with ushering the professional game to its highest level of popularity during the 1980s and 1990s: Larry Bird, Earvin "Magic" Johnson, and Michael Jordan.
The object of the game is to outscore one's opponents by throwing the ball through the opponents' basket from above while preventing the opponents from doing so on their own. An attempt to score in this way is called a shot. A successful shot is worth two points, or three points if it is taken from beyond the three-point arc 6.75 metres (22 ft 2 in) from the basket in international games and 23 feet 9 inches (7.24 m) in NBA games. A one-point shot can be earned when shooting from the foul line after a foul is made.
A limited number of time-outs, clock stoppages requested by a coach (or sometimes mandated in the NBA) for a short meeting with the players, are allowed. They generally last no longer than one minute (100 seconds in the NBA) unless, for televised games, a commercial break is needed.
There are limits placed on the steps a player may take without dribbling, which commonly results in an infraction known as traveling. Nor may a player stop his dribble and then resume dribbling. A dribble that touches both hands is considered stopping the dribble, giving this infraction the name double dribble. Within a dribble, the player cannot carry the ball by placing his hand on the bottom of the ball; doing so is known as carrying the ball. A team, once having established ball control in the front half of their court, may not return the ball to the backcourt and be the first to touch it. A violation of these rules results in loss of possession.
Offensive plays are more varied, normally involving planned passes and movement by players without the ball. A quick movement by an offensive player without the ball to gain an advantageous position is known as a cut. A legal attempt by an offensive player to stop an opponent from guarding a teammate, by standing in the defender's way such that the teammate cuts next to him, is a screen or pick. The two plays are combined in the pick and roll, in which a player sets a pick and then "rolls" away from the pick towards the basket. Screens and cuts are very important in offensive plays; these allow the quick passes and teamwork, which can lead to a successful basket. Teams almost always have several offensive plays planned to ensure their movement is not predictable. On court, the point guard is usually responsible for indicating which play will occur.