This year’s Six Nations will adopt the 20-minute red cards that were trialled during the autumn.
For the first time in the Championship, players sent off for technical offences can be replaced by a team-mate after 20 minutes have elapsed in an initiative design to punish players and not teams.
However, referees can still award full and permanent red cards for deliberate and dangerous acts of foul play.
After its success debut during the Autumn Nations Series, referees will continue to explain any important decisions within games to spectators through a microphone.
To speed up the game, kickers have 60 seconds after a try has been scored to take conversions, while scrums and line-outs must be formed within 30 seconds.
A global law trial designed to protect scrum-halves at the base of rucks, mauls and scrums will also come into effect for the Six Nations.
The Six Nations begins with Wales’ trip to France on Friday, January 31. Scotland host Italy and England travel to Ireland on the following day.
