Ireland and Scotland were pooled together in Pool A at Wednesday's Rugby World Cup 2019 draw, with Japan also in their section.
Ireland will be favourites to win Pool A as they set about trying to improve a World Cup record that has never seen them progress beyond the quarter-finals.
Irish head coach Joe Schmidt said of his side's task: "I think it's very hard to assess where teams are going to be in two years' time."
He has been impressed by Japan’s “upward curve” and said: “They got very close to beating Wales last autumn, and obviously their heroics in the last World Cup were pretty spectacular.”
Saying Ireland would “need to be on our mettle” for a possible clash with Romania, Schmidt also suggested the clash with the team from Oceania would be a significant test.
He told World Rugby: “We lost to Scotland recently so it’s a mixed bag but I think it’s incredibly exciting to draw the host nation in that the crowd, the enthusiasm and the interest in that game is going to be huge.”
Host nation Japan are likely to feature strongly, while Scotland, who beat Japan in the 2015 pool stage, will not lack confidence. The group also includes the top European qualifier, possibly Romania, and a play-off winner completing the picture.
Reflecting on the draw, Japan head coach Jamie Joseph said: "Any pool that we were going to get put in was going to be a big challenge.
“But now there’s some certainty around it, we can start our planning and we are really looking forward to it.
“I think we are fortunate in that we play Ireland in June, so that will give the players a good understanding about that team because Japan haven’t beaten Ireland or Scotland to date, so we know that the challenge is going to be big.
“There is still a long time to go — we are still a couple of years away — and I guess all teams are blooding some young players who are coming through, so it’s going to be really exciting.”
Scotland head coach Gregor Townsend declared his first reaction to the draw was "excitement".
He said: “Ireland have been one of the most competitive and most improved sides over the past few years and a lot of that is to do with their quality of players and the influence of head coach Joe Schmidt.
“They have shown real consistency over the past two or three years. They are one of the best teams in the world. Whichever side we drew from the top band was always going to be very tough.
“On the other hand, we know Ireland pretty well and have a couple more opportunities to play them before the World Cup, while we also know a lot about their players through the Guinness Pro12.
“Japan obviously made a memorable impact at the World Cup two years ago, beating South Africa, and will have tremendous support going into the tournament. They’ll be targeting getting out of the pool and I’m sure that we’ll see them play close to their best in every game.”
