recent development, as they were first used in the 1970 World Cup. It was a reaction to several problems in the game, including the use of violent kicks and fouls that would injure opposing players. Some teams were infamous for using this tactic to get injure an opposing player and therefore gain a numerical advantage (in-game substitutions were not allowed in soccer, in most cases, until the late 1960s). Refs sometimes warned or expelled players, but it was somewhat ad hoc and inconsistent, and sometimes it was unclear who had been cautioned, or expelled.

Also, the use of cards made it easier for refs and players to overcome the language barrier, as players and refs often spoke different languages and didn't understand each other. This was especially true in international tournaments, and in leagues with many foreign players. The use of the colored cards helped to resolve this issue.

The 1966 World Cup was particularly violent and brutal, and the card system was instituted for the next World Cup.