Tokyo - Japan's rugby captain Michael Leitch warned that the "Brave Blossoms" will fear no one at this year's World Cup as the hosts target a place in the knockout stage for the first time.

The New Zealand-born flanker shot to fame four years ago when Japan won three games under Eddie Jones, including an astonishing 34-32 victory over two-time champions South Africa.

Just 100 days before Japan kick off the World Cup against Russia, Leitch is backing his side to make history.

"Our main objective is get out of the pool stages," he told AFP in an interview.

"Once we get out of there we've either got New Zealand or South Africa, and we're not going to lay down for them either."

Leitch's bold decision not to kick for a draw with Japan trailing the Springboks by three points in the last minute of their 2015 opener in Brighton led to Karne Hesketh's famous try - securing the World Cup's biggest upset.

"That day I had a coffee with Eddie and he said 'Just go with whatever you want to do!' - that's probably the best advice Eddie ever gave me," said Leitch.

"If I was smart I would have retired then and there and gone into the Hall of Fame," added the 30-year-old, who has become the face of Japanese rugby.

Leitch, who moved to Sapporo in northern Japan as a 15-year-old, credits Jones with laying the foundations for Japan's success with his punishing training sessions.

"Back then we didn't know what hard work was," said the hulking back-row forward, who is currently recovering from a groin injury.

"Eddie was all about the finer details. We had to just turn up and train - and play exactly how we trained."

But Leitch believes Japan - who also face Ireland, Scotland and Samoa in Pool A this year - have improved under current coach Jamie Joseph.

"With Jamie's style the players have a lot more responsibility and accountability for their actions," said Leitch after a workout at his Japanese club Toshiba Brave Lupus.

"The team has a lot more attachment to what we're doing this time around."

But Leitch, who is targeting a return at next month's Pacific Nations Cup, played down the pressure on Japan to progress from their group after their 2015 heroics.

"There's a lot of expectation," he admitted. "But I don't see that as pressure. I'm quietly confident we'll get the job done."

Leitch predicted that Japan's tournament opener on September 20 could be their most difficult test, noting how they only just pipped the Russians by five points last November.

"That will be the hardest game - coming up against Russia, the mental game," he said.

"That's the game they're targeting," added Leitch. "If they're going to beat someone it's going to be Japan, so we've got to be ready."

Leitch, who along with world number one tennis player Naomi Osaka, carries the flag for mixed-race or foreign-born Japan athletes, will lead out a multi-cultural World Cup team with roots in New Zealand, South Africa and the Pacific islands.

He also has plans to bring Mongolian teenagers to Japan to play rugby on an exchange programme that mirrors his own development.

"I'm not 100 percent rugby," smiled Leitch, born to a New Zealand father and Fijian mother.

"But this year's a bit different - I have been a bit selfish and everything is about rugby."

Leitch, who owns a coffee shop in Tokyo, is itching for the serious business to begin after a lengthy injury layoff.

A calming influence for Japan during the heat of battle, he is none the less happy to avoid the limelight.

"The way I operate in the team, I'm just an organiser - I don't want to be the hero," said Leitch.

"I just try to lead by example. When things are going good I'm in the background, but when the shit hits the fan then I'm the one who will show face and give direction."