Japan rugby coach John Kirwan has started sending his players to brutal sparring sessions with giants of the sumo world in a bid to toughen up his side.

The former New Zealand great, whose team emerged from last year's rugby World Cup with credit, watched from a safe distance as his players took a pounding from the roly-poly wrestlers.

"There's techniques you can use in the scrum," Kirwan told Japanese media on Thursday.

"The speed at the face-off can help with the hit in the scrum."

His players were not quite so enthusiastic about taking such a battering.

"It's a totally different ball game," winced Japan lock Hitoshi Ono, sporting the traditional buttock-bearing "mawashi" loin cloth worn by sumo wrestlers. "These boys are huge!"

Japan's "Brave Blossoms" bowed out of the World Cup with their pride intact after a 12-12 draw with Canada in their final Pool B game.

Although trounced 91-3 by Australia and 72-18 by Wales, Kirwan's side were unlucky not to beat Fiji, losing 35-31 to the Pacific islanders.

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