Many officials still lack experience in nuances of game-changing technology

FLORENCE, Italy - The first time the referee makes a sign with his fingers and consults a screen on the sideline, the controversial VAR - video assistant refereeing system - will make its World Cup debut at Russia 2018.

After experiments in several FIFA tournaments, Serie A in Italy and the German Bundesliga this season, the technology 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.

"It's about avoiding major and obvious mistakes, not refereeing with technology," said Pierluigi Collina, chairman of the FIFA Referees Committee, during a VAR training program organized at the Italian national training center. "The goal has never been to check every minor incident."

At the World Cup, 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.

"VAR can be our best friend because it's no longer possible to make a crucial error," said Dutch referee Bjorn Kuipers.

The main sticking point remains the inexperience of some of the referees who have rarely used the new technology before the World Cup.

"All the referees involved have participated in numerous tournaments where video assistance has been used," French referee Clement Turpin told AFP.