England coach Eddie Jones does not want to see Japan introduced to the Six Nations at this stage but would be open to the Brave Blossoms playing Northern Hemisphere sides on bye-weeks.
Hosts Japan reached the quarter-finals of the Rugby World Cup for the first time this year, stunning both Ireland and Scotland in the process.
However, Jamie Joseph's side are not involved in annual international competitions either in Europe, with the Six Nations, or in the Southern Hemisphere, with the Rugby Championship.
Japanese club Sunwolves play in Super Rugby alongside teams from New Zealand, Australia, South Africa and Argentina, yet the Daily Mail reported the Brave Blossoms could be set for a Six Nations invite.
Jones, who led England to the World Cup final, previously coached Japan and wants to see the team develop. However, he believes the international season is long enough already for now.
"I think 10 internationals a year in the Northern Hemisphere is about right," Jones told BBC Sport. "To increase the Six Nations would mean taking away from somewhere else.
"I'd bring Japan in for bye-weeks, so they'd play two games over the next three of four years to prove they are strong enough to compete consistently."
While Japan are still relative newbies at the highest level, Jones believes their World Cup performance can be a lesson to Scotland, who disappointed in missing out on the last eight.
"Gregor [Townsend] has got them back playing how a Scotland side should play," he said. "[Being small] makes it difficult, but you can have one-off success like Japan have had.
"You've got to pool all your resources into being the best 'small' team in the world. That means you look at everything you do, at how you can win ball quickly - particularly from set-pieces.
"You look at how you can win the ball quickly from the breakdown and you need a consistent programme for four years to be at your best to do that.
"You have to play quick, you have to have a varied attack and it takes a lot of cohesion to play that way."