Japan's preparations for its first test match under Jamie Joseph took another hit Monday with a further four players dropping out of the extended training squad.

Yoshitaka Tokunaga was a no-show when the players met up Sunday evening as a result of injury, while Hitoshi Ono, Kazuhiko Usami and Keita Inagaki left Monday morning after being declared unfit.

"It's not ideal. We have lost some experienced players which is unfortunate," said Joseph, whose side plays Argentina at Prince Chichibu Memorial Rugby Ground on Nov. 5, before traveling to Europe to play Georgia, Wales and Fiji.

Kosei Ono, Tim Bennetts and Male Sa'u pulled out last week, and Joseph has now called in an additional seven players since naming a 36-man training squad on Oct. 3.

The latest to join were back-row forwards Yoshiya Hosoda and Uwe Helu, who arrived in the afternoon. But Joseph, who names his final 30-man squad on Friday, was trying to look at the positives rather than the negatives.

"No Japan team has ever gone in against Argentina thinking they are going to win," he said. "These young players are keen to go. They are fresh and have got nothing to lose."

However, Joseph did admit the rash of injuries was a cause of concern.

"It's something we have to look at," he said. "The players are going from Top League to Super Rugby to test matches, and it's taking its toll."

Monday's training session saw the team spend some time on defensive drills before the forwards and backs split up to work on their own skill sets.

The backs were put through their drills by Tony Brown, with a special emphasis on handling quickly while under pressure.

"We've had three trainings now and the guys are picking up how we want them to play, understanding our game plan and the detail we want to put into our game," said Brown.

"There's a lot for them mentally but hopefully there's a good base and hopefully we can come in and prepare really well for Argentina next week."

As to what fans can expect of the new Brave Blossoms, Brown said he and Joseph had their own vision of how Japan should play.

"We coach a bit differently from Eddie (Jones) so it will be different from the way Japan has played in the past," Brown said. "We are just trying to get the guys understanding how we are going about that. It will take a bit of time but we are confident the boys will pick it up pretty quickly."

It was a view shared by Shota Horie, who is likely to captain the side in the self-imposed absence of Michael Leitch.

"We are understanding the strategy much better than we did two weeks ago," he said. "This camp has been really good in letting the players know what it means to play for Japan. Everyone has a responsibility and commitment and is contributing to the team discussions."