This year six nations will adopt the 20-minute red card that was trialled in the autumn.
For the first time in the Championship, players sent off for technical offenses can be replaced by a teammate after 20 minutes have elapsed in an initiative designed to punish the players, not the team.
However, referees can still award full and permanent red cards for deliberate and dangerous foul play.
Following its successful debut in the Autumn Nations Series, referees will continue to explain any important decisions in-game to the audience via a microphone.
To speed up the game, kickers have 60 seconds after attempting a conversion, while scrums and line-outs must be made within 30 seconds.
A global law trial designed to protect the ruck, maul and scrum-half at the base of the scrum will also be in effect for the Six Nations.
The Six Nations begins with Wales’ tour of France on Friday 31 January. The following day Scotland host Italy and England visit Ireland.
