Japan have withdrawn from the so-called Eight Nations tournament this autumn.
Members unions of the Six Nations plus Japan and Fiji were set to form the teams for the competition, which is set to run between November and December.
But the JRFU have faced a number of dilemmas in recent weeks after the country's government reintroduced travel restrictions in light of a spike in COVID-19 cases last month.
That has affected many of the team's coaches who are based overseas from joining up with the squad to prepare to the Eight Nations, and led to the JRFU pulling out according to Kyodo News.
Their withdrawal creates a bigger problem for the JRFU, with Japan's last Test being their quarter-final exit to the Springboks at last year's Rugby World Cup.
As for the Six Nations, the concluding round of the 2020 campaign is set to be contested in the final week of October.
Fiji's place in the tournament which follows the end of the Six Nations has already been placed into doubt after head coach Vern Cotter voiced his concerns over how the competition had been structured.
The Pacific Island nation had been grouped into a pool of four alongside England, Ireland and Wales, while Japan had been grouped with Scotland, Italy and France.
An unbalanced mix-up favouring Japan in the view of the Kiwi, who said: “I just wonder how we got into the pool with England, Wales and Ireland when Japan, Italy and Scotland are all lower in the world rankings.”
