Japan are in talks with both the Six Nations and Rugby Championship over entering an expanded version of the competitions.
However, the CEO of the JRFU says the Rugby Championship would be their preferred destination.
The Brave Blossoms have regressed since their World Cup heroics of 2019, in large part due to being inactive in 2020 on account of the Covid-19 pandemic.
Jamie Joseph's side won just one of their six Test matches last year, with two defeats to Ireland in Dublin, the second of which being a 60-5 drubbing at the Aviva Stadium.
Gaining entry to an annual Tier One competition is the next step for Japan to take, with former international and current CEO of the Japan Rugby Football Union Kensuke Iwabuchi confirming that they are speaking to both the Six Nations and Rugby Championship, the latter of which would be the most suitable.
"For our national teams to have not played for the best part of two years has had a huge impact," Iwabuchi said.
"We definitely need to be involved in regular international competition, otherwise we cannot expect to maintain consistently strong sides.
"Europe has the Six Nations and the Southern Hemisphere have the Rugby Championship.
"We're in discussions with both competitions, but while Japan is technically in the Northern Hemisphere, from a time-zone perspective we’re closer to Australia, New Zealand and the Pacific nations, so it probably makes sense to connect with their competitions."
Japan have previously been aligned to SANZAAR via the Sunwolves, with the Tokyo-based franchise competing in Super Rugby from 2016 to 2020.