Diagonal system of
control
From Wikipedia, the free encyclopedia
Diagram of a left diagonal system of control
The diagonal system of control is the system of positioning used by match
officials (referees and assistant referees) in association football (soccer).
The diagonal system of control (DSC) can best be described by outlining the
basic duties of the three match officials.
First, the two assistant referees each patrol half of a single touchline on
opposite sides of the field. For example, on a field running north-south, one
assistant referee (AR) would run on the eastern touchline from the north goal
line to the halfway line, while the other assistant referee would run on the
western touchline from the south goal line to the halfway line. In general, the
assistant referees' duties would be to indicate (using their flags); when an
offside offence has occurred in their half, when a ball has left the pitch, and
if a foul has been executed out of the view of the referee (typically in their
quadrant of the field). Generally, the ARs will position themselves in line with
either the second to last opponent or the ball � whichever is closer to the goal
line � in order to better judge offside infractions. However, the assistant
referee will have specific positioning with respect to corner kicks, penalty
kicks, and throw-ins.
The center referee patrols the length of the field, generally running in a
diagonal pattern from the southeast quadrant of the field towards the northwest
quadrant; hence the term "diagonal system of control". Note that this pattern is
not a specific route but a general guideline that should be modified to the
style of play, nature of the game, the location of play at a given time, etc. In
some cases the referee may even exit the field if it aides in his decision
making ability. The main idea is that the referee and assistants using the DSC
should be able to position themselves quickly and easily to observe the
important aspects of play (offside, ball in or out of play, goal-scoring
opportunities, challenges for the ball) from multiple angles with multiple sets
of eyes.
Note that the description above refers to a left diagonal system of control,
known as "running a left". If, before the match, the center referee on this
field decides to run from southwest to northeast, then the assistants must
position themselves accordingly and the result will be a right diagonal system
of control, otherwise refereed to as "running a right".
In international matches the left-wing diagonal shown above has been universal
since the 1960's. It is now predominant across the world although a minority of
referees in England still run the opposite diagonal and a very small number
switch diagonal at half-time. The latter approach was mandatory in the Football
League until 1974 but since officials have had the choice most have opted to
stick with the same diagonal throughout a game.
Retrieved from "http://en.wikipedia.org/wiki/Diagonal_system_of_control"