Volleyball is a team sport in which each team consists of six players. During a game players can use a formation depending on the players' skills and types of attack techniques the team is going to use. There are three basic formations: 4-2, 6-2, and 5-1.
The 4-2 formation has four hitters and two setters. The setters usually set while in the front row position and pass while in the back row. Because of the rotation rule in volleyball in 4-2 formation the setters usually line up opposite each other, so that the team always has one setter and two attackers in the front row. In the international 4-2 formation, the setters set from the right front position.
The disadvantage of this formation is that there are only two front attackers, which weakens the team's offense. That's why the 4-2 is used only in beginner's play, or when a team doesn't have good hitters.
In the 6-2 formation all six players act as hitters at any time and also two of the hitters become setters, as needed. The advantage of this formation over the 4-2 is that there are always three hitters in the front row and the setter comes forward from the back row to set.
This formation requires that the two setters line up opposite each other. Two middle hitters and two outside hitters are also aligned opposite each other in the rotation, so there is always be one of each position in the front and back rows.
The 6-2 formation is used when all six players are good hitters. However, two people have to be also capable of performing the highly specialized role of the setter. At the international level, only the Cuban National Women's Team employs this kind of formation.
The 5-1 formation has five hitters and only one setter. The team will have three front attackers, when the setter is in the back row and only two front attackers, when the setter is in the front row. Unlike in the 6-2 formation, the setter doesn't have to alternate between setting and hitting and can focus on his or her job.
The player opposite the setter is called the opposite hitter. The opposite hitter may be used as a third attack option (back-row attack) when the setter is in the front row. It increases attacking capabilities of the team.
The big advantage of the 5-1 system is that the setter always has 3 hitters to vary sets with. Also, when the setter is in the front row, he or she is allowed to jump and "dump" the ball onto the opponent's side which often confuses the other team.