World Rugby vice-chairman Agustin Pichot says Japan could join the Rugby Championship within two years.
The Brave Blossoms reached the World Cup quarter-finals for the first time this year after beating Ireland and Scotland, prompting calls for them to be included in Sanzaar's annual tournament.
'In a dynamic world, 2021 would be a good target,' Pichot told The Times
after being asked when Japan could be expected to join the Springboks, All Blacks, Wallabies and Argentina in an expanded competition.
Los Pumas came third at the 2007 World Cup but it took another five years before they were added to what was then known as the Tri-Nations. Pichot said things should happen quicker for Japan.
'We've done this before -- we know how to do it,' he said.