In Association football, the formation describes how the players in a team are positioned on the pitch. Different formations can be used depending on whether a team wishes to play more attacking or defensive football.
Formations are described as the number of players in each area from the defensive line (not including the goalkeeper). For example 4-4-2 describes the formation as having: 4 defenders, 4 midfielders and 2 forwards. Conventionally, the formation can be described with 3 numbers, although 4-numbered (e.g. 4-4-1-1) and 5-numbered formations (e.g. 4-1-2-1-2) can be used. The numbering system was not present until the 4-2-4 system was developed in the 1950s.
The choice of formation is often related to other tactical choices, such as the choice of playing style. Formations can be deceptive in analysing a particular team's style of play, i.e. one team could play 4-4-2 and work defensively, whereas their opposition using the same formation could play much more attacking football.
Formations can be altered during a game, but this requires adaptations of the players to fit in to the new system. This can be due to a team wishing to change their offensive or defensive strategy, or even due to the loss of a player. Some formations also lend themselves to dynamically changing as players move up and down the field, e.g., the Brazilian 4-2-4 could effectively become a 2-4-4 during a match.
Formations are used in both professional and amateur football matches. However, in amateur matches these tactics are sometimes adhered to less strictly due to the lesser severity of the occasion. Skill and discipline on behalf of the players is also needed to effectively carry out a given formation in professional football. Formations need to be chosen with the players available in mind, and some of the formations below were created to address deficits or strengths in different types of players.