Back in the cold remove of a tv studio, or maybe even on a couch or a bar stool, Ireland’s sometimes laboured 36-20 win over Japan might not have set pulses racing but the enjoyment felt by a quartet of new Irish rugby internationals celebrating a win together on debut was infectious.Sean Jansen, at 27, is the most senior of the foursome, as well as the sole starter and the standout, with a try and a worthy man of the match award. Sam Illo, at 25, is the late-blooming second eldest of them, the dynamic Ulster flanker Bryn Ward, who turns 22 next Friday, is the second youngest.And then there’s Billy Bohan. All four spoke with the media in the mixed zone and though the youngest, Billy Bohan, is 20 years old, he seemed almost the least fazed about it all. Bohan cut his teeth in a young Corinthians side last season and even last autumn was playing some games in Division 2A of the AIL. “It’s weird to hear that. A few years have gone by pretty quick, from playing 2A to here. I’m not sure how many months it is, but it feels like it’s been a few years since that, to be honest. So it’s funny.”“Corinthians has been class, just the team environment when I went in last year. Such a young group, so it was such good craic playing with them. Obviously, the seriousness in the Connacht set-up. Then you go out to Corinthians to play on the weekend, and it’s just great fun. I really enjoyed my time there.Ireland's Sean Jansen is tackled by Japan's Tiennan Costley. Photograph: Ben Brady/Inpho Yet another rugby product from Kildare and specifically his hometown Kilcullen and the Newbridge College conveyor belt under Johne Murphy and co, it perhaps reflects Bohan’s temperament that he made the brave decision to move to Galway when offered a full academy contract with Connacht as opposed to a sub academy deal with Leinster.One can maybe understand Leinster’s relative reticence over a young prop, and they weren’t to know loose-heads would be dropping like flies this season, but they’ve evidently let a good one go. Having been a near ever-present in last season’s Ireland Under-20 Six Nations games and the Under-20 World Cup, Bohan has flourished this season under Stuart Lancaster’s tutelage and willingness to give young players like himself and Illo opportunities. [ Andy Farrell: ‘How Sean Jansen attacked the game as a debutant, it’s a learning for everyone’Opens in new window ]His decision to head west as a young man couldn’t have worked out any better.“No, it couldn’t. It was a tough call, but it’s only two hours west, so it’s not too bad. Andrew Browne, who was the academy coach there, who was my Ireland U19s head coach, he was a big reason why I moved west, because I had a good relationship with him, and he’s been huge for me, my development. I’d like to thank him very much.”Ireland's Sam Illo is tackled by Japan's Hayate Era and Keijiro Tamefusa. Photograph: