The referee makes the sign of a screen with his fingers and goes to consult a screen on the edge of the pitch – the VAR, video assistant refereeing system, will make its World Cup debut at Russia 2018.
After experiments in different FIFA tournaments, Serie A in Italy and the German Bundesliga this season, the principle is now well known in most countries.
VAR can be used in four scenarios – after a goal has been scored, for penalty decisions, red card decisions or for a case of mistaken identity of a player who has been booked or sent off.
In Russia, 13 referees will officiate exclusively by watching the control screens. And some of the 35 referees selected to officiate on the pitch will also move into the role of video referees for one or more matches.
The main sticking point remains the inexperience of some of the referees who have rarely got to use the new technology before the World Cup.
Behind VAR, there will be the VOR – Video Operation Room – where the numerous assistants will be seated, along with four technical operators.
FIFA will have a single operational center – as is the case in the Bundesliga – which will be installed in Moscow and connected to all stadiums via a fiber optic network.
Pierluigi Collina, chairman of the FIFA Referees Committee and formerly considered one of the world's finest referees, also stressed that VAR officials would never have to cover more than one match a day.
Two additional cameras will be used at the World Cup, exclusively dedicated to offside decisions.
In all cases, messages will be broadcast on giant screens in stadiums so spectators can see what decision is reached by VAR: goal, no goal, offside.
But no replays will be shown until the on-pitch referee has made his decision.