Coverciano - Four video assistant referees (VAR) will be present at every game at the World Cup in Russia with replays to be shown on giant screens inside the stadiums, FIFA said on Wednesday.
"Everything will be centralised in a single location in Moscow and all referees will be based in Moscow," explained FIFA's referees' chief Pierluigi Collina during a training seminar organised at Coverciano, near Florence.
Over the next two weeks two groups of 36 referees and 63 assistants will be trained for the World Cup in Coverciano, with workshops organised on the VAR system which will be used at the tournament for the first time.
Another former Italian referee Roberto Rosetti explained how VAR would work during the tournament.
"There will be four VAR officials. The VAR principal will communicate with the main referee and can suggest that he comes to verify images on the sidelines," explained Rosetti.
"The VAR assistant number one will be in charge of following the match live while the review is taking place. VAR assistant number two will be specially in charge of off-side."
Two specially-adapted cameras will be used to watch out for off-side players during the World Cup.
A third VAR assistant will be in charge of supporting the VAR principal, focusing on the respect of protocol and to assure good communication between the whole team.
In addition to the VAR officials there will also be four technicians in charge of screens and camera angles with a FIFA representative present to relay decisions with explanations on giant screens.
"We have to remember that the the very clear objective and the success of VAR will also depend on how it is understood," said Collina.
"It's about avoiding clear and obvious major errors. It's not a question of refereeing the match with technology. The goal has never been to check every minor incident."