With just five days of training behind it, Japan's new Super Rugby side heads into its only warmup game knowing it needs to get out of the blocks flying.

The Sunwolves kick off their season on Feb. 27 against the Johannesburg-based Lions and will do so with just 80 minutes of rugby behind them.

While the other teams in the competition are all playing a number of games against other Super Rugby franchises, the Sunwolves solitary game is a charity event Saturday against a Top League XV that bears little resemblance to the sides they will face over the course of the next five months.

"It's not ideal preparation, is it?" coach Mark Hammett said Friday at Aichi Prefecture's Toyota Stadium.

"But as I've said all along, in the first year there's going to be hurdles, struggles and learnings. While we need to prepare for now, we also need to have a good eye for the future."

Part of those "learnings" have seen three players, not originally included on the roster when it was announced on Dec. 21, added to the team.

Hooker Futoshi Mori, lock Kazuhiko Usami and scrumhalf Kaito Shigeno have been drafted in and all three will play a role on Saturday.

"We've got a couple of injuries and we also identified that we need to strengthen our back row," said Hammett. "By bringing in Usami we can use one of the other guys (in the pack) in a back-row position.

"I also think in Super Rugby it's critical that you have a squad of around 40. That's my preferred number and there are still a couple of other players that we are still negotiating with."

With a number of players on the squad having never played in Japan before, Hammett said the players have worked very hard on their communication skills in the short time they've been together.

He also said flyhalf Tusi Pisi would have a key role.

One of the few players on the squad with Super Rugby experience, Pisi has spent the last seven years in Japan and his partnership with Suntory Sungoliath teammate Atsushi Hiwasa at halfback will be key to the Sunwolves getting off to a good start.

"We have some really good members in our strategy group," said Hammett. "Tusi, Yu (Tamura), Haru (Harumichi Tatekawa), Shota (Horie) and Atsushi. I've been getting them to communicate at team meetings and I like to run the leadership groups in the same way."

One other person with a key role to play in the coming weeks and months is assistant coach Atsushi Tanabe.

A key member of Robbie Deans' staff at Panasonic Wild Knights, Tanabe's ability to communicate in both Japanese and English, as well as the tactical knowledge he's built up working alongside Deans, Tony Brown and Phil Mooney, will be invaluable for the fledgling team.

"I've been really impressed with how quickly some of the guys have been picking things up," the former fullback said.

"The guys from the Japan national team and Tusi have been leading really well and will be key players.

"There are things we cannot control but we've just got to get straight into it. I really think we can make an impact. Everyone thinks this is a boat that is half sinking. But I think we can make it float and really show what Japanese rugby can do."

With both the Sunwolves and the Top League XV fielding 30-plus players, there are some who have said Saturday's contest will resemble a gentle preseason game rather than a dress rehearsal for what is arguably the toughest regional rugby competition in the world.

Hammett, however, is hoping for a full-on physical encounter.

"I've told the players to forget the tactical things and bring their bodies to the game," he said. "Training without an opposition is easier than having a side run back at you. I expect there to be mistakes tomorrow but as I have told the team, what's important is how we react to them."