The 2023 Rugby World Cup in France has been extended by one week to allow all teams at least five days preparation before pool matches.
Player squad sizes will also increase from 31 to 33, with the decisions designed to improve player-welfare standards.
World Rugby chairman Sir Bill Beaumont said: “This is a landmark day for Rugby World Cup and the sport.
“As a rugby father, former player, fan and administrator, player welfare is at the very top of my agenda. This continued focus for a player-first decision reflects that commitment.
“Men’s Rugby World Cup schedules are difficult to balance owing to the format of four pools of five teams.
“Japan 2019 provided the best balance and best-ever welfare outcomes, but we still had a limited number of relatively short rest periods between some matches.
“In collaboration with France 2023 and International Rugby Players, this decision means that every player and every team will have a fairer chance to perform to their potential in every fixture, and now we will work with the teams to reduce overall load for players. Including travel.”
Emerging nations have often been punished at past World Cups with less recovery time between games.
But the pool phase will now be extended by a week to accommodate the additional rest day requirement. The full schedule will be announced on Friday.
The 10th edition of the tournament will kick off on September 8, 2023, and conclude with the final on October 28, 2023.
Former Ireland captain Brian O’Driscoll, the International Rugby Players representative on the Rugby World Cup Board, said: “The game has become too physical and competitive for short turnarounds.
“All teams have found it tough, particularly those without the squad depth of the major nations.
“This is a positive step forward for the game and further demonstration of how International Rugby Players and World Rugby can work together towards better outcomes.”
World Rugby reported its best player welfare outcomes at the 2019 World Cup in Japan.
Injury replacements reduced from 2.08 per match in 2015 to 1.13 in 2019, while there was a 28 per cent overall concussion incidence decrease compared to the 2018 elite competition average.
There was also a 37 per cent reduction in tackle concussion incidence compared to the 2018 elite competition average.