The November Test matches will include the introduction of a trial of 20-minute red cards for the first time in the Northern Hemisphere.
The news was confirmed Friday with referees having an option to issue two types of red cards.
If a player is guilty of "deliberate and dangerous" foul play, they can still be sent off for the whole match. But technical offences can be penalised with a 20-minute red card. If this is awarded, the player will leave the pitch for the entire match, but can be replaced by a substitute after 20 minutes is up, meaning the team will be back up to 15 players for the rest of the game.
The 20-minute red card will be in play for the 21 matches of the Autumn Nations Series, which starts on Nov. 2 with England facing New Zealand at Twickenham.
This is a controversial move, and a different variation of 20-minute red cards has already drawn strong opposition from French rugby where the French Rugby Federation argued it would be an "unacceptable step backwards on the measures put in place over the last few years to reduce head impacts."
La Rochelle head coach Ronan O'Gara said the introduction of 20-minute red cards would see the sport "reentering dangerous territory" and called the measures "nonsense."
But this latest model is tweaked, meaning the referee can use a 20-minute penalty for technical offences, like accidental head contact. "Everyone in rugby understands that there is a huge opportunity to capture the attention of a far broader audience, alongside catering for its existing and passionate fanbase," Six Nations chief of rugby Julie Paterson said.
"The law trials are just one step towards exploring this opportunity, and the trials running throughout the Autumn Nations Series will hopefully enhance the experience for fans, whilst helping explain some of the decisions taken 'live' and to embrace but also explain the nuances that are part of what make rugby so unique and special.
"No trial or subsequent change is considered without utter confidence that player safety and welfare is front and centre though. First and foremost, we need to look after the players and their interests, and the trials we have opted to use this November deliver on this commitment."
Other trials in play during the end of year internationals include scrum and lineout countdown clocks and referees explaining decisions at points during the match via the stadium loudspeaker.