With the anticipation growing ahead of next Wednesday’s tournament opener against France at Stade Aime-Giral in Perpignan (kick-off 9pm local time/8pm Irish time), this proved to be a very worthwhile exercise for Noel McNamara’s young squad.

While the set-up of the game was slightly unorthodox (there were three periods of 20 minutes each rather than the standard 40 minutes per half), the Clare native was able to work on a number of combinations ahead of a hectic schedule on French soil.

All five uncapped players named in Ireland’s World Rugby U-20 Championship squad yesterday were handed starts, with Tom Roche and Dan Hurley filling the wing berths, UCC’s Peter Sylvester joining Tommy O’Brien in the centre, and Trinity pair Dan Sheehan and Joe Byrne combining with James French in the front row.

With injuries part and parcel of the international season’s Under-20 summer showpiece, Ireland will keep a number of players on stand-by, and today’s warm-up fixture saw the likes of Dylan Tierney, Bryan O’Connor, John Hodnett, Jack Daly, Angus Kernohan, David McCarthy, Ronan Foley and Patrick Patterson all get game-time off the bench.

Starting out-half Conor Dean plunged a penalty into touch to set up the opening try in the ninth minute. From the resulting lineout, hooker Sheehan crossed in clinical fashion. Dean’s tricky conversion attempt was wide of the mark and Japan quickly fired back at the opposite end.

Following an overlap on the left, winger Yoshiyuki Koga was released by Asipeli Moala for a try in the corner. Hiroto Mamada added a terrific touchline conversion for a 7-5, and UCD clubman Foley entered the fray soon after, replacing newly-appointed Ireland captain Caelan Doris whose injury-enforced withdrawal was just precautionary with the tournament now only a week away.

Foley, who joined Ulster duo Joe Dunleavy and Aaron Hall in the back row, made an immediate impact with a converted try, powering over off the back of an attacking scrum. That made it 12-7 to Ireland at the first break, and a flurry of substitutions did little to break up the Irish momentum on the restart.

Harry Byrne got on the end of a sweeping move to claim Ireland’s third try which he converted himself. He also added the extras to a 24th minute score, an enterprising counter-attack from the Irish back-line putting Japan on the back foot and loosehead Jordan Duggan applied the finishing touches on the right hand side.

He was joined on the scoresheet by fellow front row Tierney from Corinthians, who profited from excellent approach work by Ballymena clubman Kernohan to touch down in style. The scoring blitz put significant daylight between the sides, but Atora Hondo’s try, at the end of a prolonged spell of pressure, boosted the Japanese ahead of the closing 20 minutes.

Nonetheless, the Ireland U-20s quickly wrestled back control with replacement scrum half Patterson pouncing on a loose ball to race over the Japanese line. His UCD club-mate Byrne landed the conversion and the hosts did not have long to wait for the their seventh and final try of the day.

Roche was picked out in space on the right wing and the dynamic Lansdowne winger broke over at high speed for an unconverted score. Japan ended the game with a similarly well-worked finish on the left, but it was Ireland who took the spoils, building further momentum on the back of last week’s 52-14 victory over Scotland in Edinburgh.

IRELAND U-20: James McCarthy (UL Bohemians/Munster); Tom Roche (Lansdowne/Leinster), Tommy O’Brien (UCD/Leinster), Peter Sylvester (UCC/Munster), Dan Hurley (Young Munster/Munster); Conor Dean (St. Mary’s College/Leinster), Jonny Stewart (Queen’s University/Ulster); James French (UCC/Munster), Dan Sheehan (Dublin University/Leinster), Joe Byrne (Dublin University/Leinster), Matthew Dalton (Malone/Ulster), Charlie Ryan (UCD/Leinster), Joe Dunleavy (Malone/Ulster), Aaron Hall (Ballynahinch/Ulster), Caelan Doris (St. Mary’s College/Leinster) (capt).

Replacements used: Dylan Tierney (Corinthians/Connacht), Jordan Duggan (Naas/Leinster), Bryan O’Connor (UCC/Munster), Cormac Daly (Clontarf/Leinster), John Hodnett (UCC/Munster), Jack Daly (Garryowen/Munster), Hugh O’Sullivan (Clontarf/Leinster), Harry Byrne (UCD/Leinster), Angus Kernohan (Ballymena/Ulster), David McCarthy (Garryowen/Munster), James Hume (Banbridge/Ulster), Ronan Foley (UCD/Leinster), Matthew Agnew (Ballymena/Ulster), Patrick Patterson (UCD/Leinster).

JAPAN UNDER-20: Kyohei Yamasawa; Halatoa Vailea, Siosaia Fifita, Yuto Mori, Yoshiyuki Koga; Hiroto Mamada, Shinobu Fujiwara; Yusuke Yamada, Miyu Arai, Gakuto Ishida; Kanji Shimokawa, Ryuga Hashimoto; Kai Yamamoto, Hisanobu Okayama, Asipeli Moala.

Replacements used: Ryunosuke Momoji, Shohei Oyama, Katsuto Kubo, Kaito Aibe, Shota Fukui, Atora Hondo, Nicholas Hofua, Itsuki Kodama, Sioeli Vakalahi, Yu Saruta.