The Box-and-one defense is a particular type of defense used in basketball. The box-and-one is a hybrid between a man-to-man defense (in which each defensive player is responsible for marking a player on the other team) and a zone defense (in which each defensive player is responsible for guarding an area of the court).
In a box-and-one defense, four players play zone defense, and align themselves in a box protecting the basket, with typically the two larger (or frontcourt) players playing directly under the basket, and the two smaller (or backcourt) players playing towards the foul line.
The fifth defensive player in a box-and-one defense plays man to man defense, typically marking the best offensive player on the other team.
A box-and-one defense is usually used against teams with one dominant scoring threat. The idea is to try to shut that player down by forcing them to score against a dedicated man-to-man player, and a supporting zone. Players such as Allen Iverson and Ray Allen often faced box-and-one defensive schemes while competing for Georgetown University and the University of Connecticut, respectively.
The biggest weakness of a box-and-one defense is its vulnerability to a pass to the middle of the "box." As there is no defensive player responsible for this area of the court, good passing offensive teams are often able to exploit this gap.
One variation is the "diamond-and-one", where the four players in the box are arranged in a diamond pattern (one under the basket, two between the basket and foul line, and the fourth at the foul line). Another variation is the Triangle and Two Defense, in which three defenders play zone defense while the remaining two play man-to-man defense.
This strategy is also used in a man down situation in lacrosse. When a team has a penalty and is down a man, the team will send out a Long Stick Midfielder to add to the three Long Stick defensemen. As well there is one short stick midfielder. The Long Sticks make a tight box in front of the goal with the short stick on the crease. The four long sticks will play zone defense, with the closest man to the ball playing man to man, and the farthest splitting two offensemen. Every time the ball is passed the formation rotates to the next man. The short stick will play man to man if there is an attackman on the crease, otherwise he will join the rotation.
This strategy is also used in the sport of Ultimate, which relies on defenses sometimes similar to basketball in its mixture of man and zone formats. In Ultimate, the box-and-one is usually incorporated into a defensive strategy called the "cup," where 3 other players play a zone around the player in possession of the disc. If the boxed player is a handler (similar to a point guard in basketball) in possession of the disc, the cup will include the boxed player temporarily in their zone.