TOKYO — Japan face Tonga in the Pacific Nations Cup in Osaka on Saturday in a further test of their readiness, both on and off the field, to host the Rugby World Cup for the first time next month.

With all eyes on the Sept. 20-Nov. 2 tournament, both teams as well as organizers are viewing Saturday as a key test of their preparations.

Last weekend, Japan flew out of the blocks with four first-half tries on the way to an emphatic 34-21 victory over Pacific Nations Cup champions Fiji in Kamaishi.

Coach Jamie Joseph was so impressed with his team's performance that he has not made the wholesale changes anticipated for Saturday's match with the weakest of the Pacific Island nations.

Tinkering around the edges rather than testing out his squad players, Joseph has made five changes to his starting side from last weekend as he gets closer to his formation for the World Cup opener against Russia on Sept. 20.

"My thinking is I have prepared a team for the World Cup, no more, no less," Joseph told Kyodo News.

"We have a fair idea on who we think our best players are, but there are some positions where there is a lot of competition where we want to give everyone an opportunity," added Joseph.

Captain Michael Leitch, who started on the bench against Fiji as he returns from a groin injury, comes into the starting side at blindside flanker in place of Kazuki Himeno.

"We need to get some game time," Joseph said.

"Himeno was unlucky not to stay in the team. He played very well last week but we really wanted to give Michael some game time."

The most surprising change is on the wing where Lomano Lava Lemeki replaces flyer Kenki Fukuoka, who scored a try against the Fijians.

Fellow winger Kotaro Matshushima keeps his place for the match against Tonga after a brace of tries in Kamaishi with the outside back department looking to be a real strength for Japan at the World Cup.

"Wings are very competitive with Mano (Lemeki), Matsushima and Kenki as our three senior wingers, so we just want to give those guys an opportunity and see how the combination goes," said Joseph.

Tonga will be hoping for a positive response following their 25-17 loss to Samoa in an Apia mud bath last weekend.

In dire weather conditions, Tonga did not help themselves, having two players sent to the sinbin within minutes of each other.

Coach Toutai Kefu has brought regular captain Siale Piutau back into the centres to instil some much-needed discipline, amongst sweeping changes from the loss to Samoa.

There is a change in the halfback, with scrumhalf Sonatane Takulua and flyhalf Latiume Fosita between them bringing the experience of almost 60 tests to the side.

Tonga will return to Osaka's Hanazono stadium during the World Cup for their Pool C match against Argentina.

With Hanazono set to host four matches at the World Cup, Saturday's contest in front of a sell-out crowd of 26,500 should also prove a good test for tournament organisers off the field.

Chief organiser J Akira Shimazu said on Thursday that key lessons had been learnt from the test match in Kamaishi and they would be looking to iron out any further operational issues in Osaka.

After Saturday, Japan's meeting with South Africa in Kumagaya on Sept. 6 will be the only opportunity for organisers to host a match before the tournament begins two weeks later. — Reuters