Harlequins prop Joe Marler was dismissed for striking at the start of the second half by Scottish referee Peter Allan and front row colleague Bob Baker (London Wasps) spent 10 minutes in the sin-bin for handling on the floor.

Disciplinary problems aside, England looked slick and efficient in the teeming Tokyo rain to run in six tries, with Josh Ovens (Bath), Chris York (Harlequins), Luke Eves (Bristol), George Lowe (Harlequins) Carl Fearns (Sale Sharks) and Courtney Lawes (Northampton Saints) all touching down.

Full back Tom Homer (London Irish) missed just one shot at goal all night, adding five conversions and a penalty, and keeping the opposition scoreless is an indication of how well England scrambled and reorganised in defence.

Earlier they handed a debut to Leicester Tigers wing Jack Cobden and a first start to highly-rated Sale Sharks No.8 Fearns, whose representative career has been endlessly disrupted by injuries and Premiership calls, while Gloucester scrum half Dave Lewis won a first cap off the bench after recovering from a broken ankle sustained immediately before the start of England's Six Nations campaign.

Of the new boys, Cobden was liveliest in the opening 10 minutes when England were making unforced errors before tightening up their game on a humid evening.

Captain Eves was denied when Rory Clegg chipped through the defence with scrum half Hayat Yokoyama covering across, while Fearns was a positive influence all over the pitch.

It was his back row colleagues, though, who set England on their way after 15 minutes. Ovens's break was taken on by Clegg and the Bath flanker was on hand again to spot an opening round the side of a ruck to force his way over.

Homer added a fine conversion, then a penalty at the end of the first quarter before some more direct build-up play was finished off by York with Homer again adding the extra points.

Japan staged a brief revival after that but were picked off from first phase with the try of the game from Eves two minutes before the break.

The skipper started from deep and his angle inside Clegg flummoxed the midfield defenders, giving him room to break the line then curve away from the cover and slide over at the posts. Homer made it four out of four to secure a 24-0 interval lead.

The complexion of the game changed, though, when Marler was sent off after less than 30 seconds of the second half. It forced England into an immediate reshuffle - Ben Moon on for York - and they were briefly under pressure on their own line.

The siege was lifted by Clegg, though, who broke from deep and released Lowe on a long run for the line, Homer's conversion making it 31-0, and Japan were punished further by England's seven-man pack in the 53rd minute when Fearns picked up from the base and drove over.

They were reduced to 13 men when Baker was yellow-carded for infringing on the floor before he returned and Lawes arrived to help close out the game.

The giant Northampton lock popped up in midfield after England had rumbled up the right and nimbly strolled over between the final two defenders for his first try for the team.

England U20: Tom Homer (London Irish); George Lowe (Harlequins), Luke Eves (Bristol Rugby), Greig Tonks (Leicester Tigers), Jack Cobden (Leicester Tigers); Rory Clegg (Newcastle Falcons), Ben Youngs (Leicester Tigers); Joe Marler (Harlequins), Jamie George (Saracens), Bob Baker (London Wasps), Dan Williams (Gloucester Rugby), James Gaskell (Sale Sharks), Chris York (Harlequins), Josh Ovens (Bath Rugby), Carl Fearns (Sale Sharks).
Replacements: James Clark (London Irish) for George 51, Ben Moon (Exeter Chiefs) for York 42, Courtney Lawes (Northampton Saints) for Fearns 63, Dave Lewis (Gloucester Rugby) for Youngs 47, Rob Miller (Newcastle Falcons) for Tonks 50-62, for Clegg 62, Henry Trinder (Gloucester Rugby) for Eves 41, Graham Kitchener (Worcester Warriors) for Gaskell 71.
Scorers: Tries: Ovens, York, Eves, Lowe, Fearns, Lawes. Conversions: Homer 5. Penalty: Homer.
Sent off: Marler 41. Yellow card: Baker 58.

Japan U20: Tsuyoshi Iguchi; Tomohiro Shoukai, Kenta Nakasone, Aisea Havea, Shohei Toyoshima; Yoshikaszu Morita, Hayata Yokoyama; Kohei Yoshida, Ryohei Arita (captain), Shinsuke Ono, Ryuta Yasui, Yoshiki Niizeki, Yuta Onodera, Kouta Yamashita, Michiro Takai.
Replacements: Ryotaro Suzuki, Keita Inagaki, Hidetatu Tuboi, Kodai Matsuhashi, Takehito Namekawa, Harumichi Tatekawa, Naoya Minamihashi

Referee: Peter Allan (Scotland). Attendance: 9120