A World Rugby press release late Wednesday night from Dublin may have appeased some parties concerned by plans for a new worldwide league, but many questions remain as to how Japan will be affected.

The sport's governing body was attacked from all sides last week after reports that its proposed Nations Championship would feature the Six Nations and Rugby Championship sides, as well as the United States and Japan, with no promotion or relegation for 12 years.

The Pacific Island nations and their supporters were particularly enraged, with some calling for a boycott of this year's Rugby World Cup in Japan.

In Wednesday's statement, World Rugby said its proposal -- originally made to the relevant unions last September -- includes relegation from both the Six Nations and a six-team Rugby Championship that would initially feature Japan and Fiji.

However, there was no explanation as to how Japan -- situated far north of the equator -- would fit into the Rugby Championship, which also features New Zealand, Australia, South Africa and Argentina.

Japan Rugby Football Union Chairman Noriyuki Sakamoto told Kyodo News recently that the "assumption is Japan will participate."

However, he admitted that the new league -- which is set to start in 2022 -- could have serious consequences for Japanese rugby and that until plans become more concrete it would be difficult for the JRFU to make any long-term plans regarding the Top League and other domestic competitions.

Under the proposed plans, Japan would play the 11 other countries once, either home or away, with points accumulated throughout to rank teams on a league table. The top two teams from each conference would then play cross-conference semifinals, followed by a grand final.

This means Japan would play eight test matches, at least four at home, in July and August, a time of year when sweltering temperatures and high humidity levels raise serious concerns for player welfare. The remainder would be played in Europe in November.

As a Northern Hemisphere country, rugby is traditionally played at the highest levels in Japan from August or September to January. So, as it stands, games against the likes of the All Blacks and Springboks would, in essence, be pre-season games for the Brave Blossoms.

The JRFU is therefore faced with a number of dilemmas.

Should they move the Top League season to earlier in the year to ensure Japan's top players are ready for the new international league?

This would cause all sorts of problems given the educational year runs from April to March, meaning the top university recruits would arrive at their new club sides with the season just about over.

An alternative plan would be to have the top Japan players playing in Super Rugby, providing the Sunwolves remain in the competition, with the Top League running at the end of the year.

This would not go down well with the corporate sides, however, as they pay the wages of the Sunwolves players who would barely feature for their companies under that scenario given the November break and the need to take time off before the new Super season starts.

No wonder Japan coach Jamie Joseph says the nation is not ready for the league.

"What competition structures? What high-performance systems do we have to have in place to be able to play those sorts of teams? Under the current status quo it would be very difficult," he told Radio New Zealand.

Joseph said while the proposed league would be beneficial to Japanese rugby and would help grow the game in Japan and Asia, he had not seen any of the proposals in detail, other than reading media reports.

Joseph went on to say that more Japanese players needed to be exposed to Super Rugby at a younger age if they are to be able to make their mark in a competition such as the world league -- a somewhat ironic statement given he has kept many young players away from the Sunwolves this year as he builds toward the World Cup.

"It will be tough, but if we can improve the Sunwolves and get that team sorted out properly and (Japanese) players can all play Super Rugby year in, year out, then yeah, in the future, why not?" he said of Japan's participation in the league.

World Rugby said, "Change is always difficult, and nobody expected complex multi-stakeholder discussions to be simple, however, for a sport to grow and thrive, it must explore ways to innovate and evolve."

No doubt, they are words that the conservative JRFU need to take on board as they try to chart the future of rugby in the country hosting this year's World Cup.