With the 100-day-to-go milestone fast approaching, two well-known British rugby stars have said they think Japan will be one of the teams to watch out for at this year's Rugby World Cup.

Welshman Sam Warburton, who led his side to the semifinals at the 2011 tournament, said the Brave Blossoms would be inspired by hosting the event and he expected them to repeat their heroics from four years ago, when they won three pool games.

Meanwhile, Stuart Hogg, part of the Scotland team that beat Japan in the 2015 event (the only side to do so), believes the hosts "will put on one hell of a World Cup . . . and the opportunity to play the hosts on their home turf will be something special."

Speaking at a recent event in Britain organized by Land Rover, the official vehicle of Rugby World Cup 2019, former British and Irish Lions captain Warburton said he believes the Brave Blossoms can not only repeat their feat of 2015 when they famously beat South Africa, but surpass it and reach the quarterfinals for the first time.

"The last four years I'm sure they would have improved and the motivation for them is going to be enormous in this World Cup," he said.

"I wouldn't fancy playing Japan; there'll be much more preferable Tier 2 nations to play against than Japan being at their home World Cup. There normally is a surprise, I don't think we'll see too many surprises from the Pacific Island nations but I think Japan could cause some real trouble again this World Cup."

The 30-year-old Warburton, who led Wales to a 33-30 win over Japan in Cardiff in November 2016, said hosting the Rugby World Cup is crucial for Japan to become a performance super power.

"It's huge. I think Japan is really timely with their win against South Africa four years ago. And to grow the game now you are looking at those countries like Japan and USA — they could be super powers of the game from a performance point of view in years to come, and from a financial point of view and the fans and the player base they have is enormous as well. That's two countries in particular which I think we're doing a good job of tapping into."

Warburton said that he hoped in the future that more and more countries would be able to follow Japan, so that by 2027 there would be a number of nations capable of not just causing an upset but winning the whole competition.

"You want there to be 15 competitive teams. Right now, you've probably got eight or nine really competitive teams. If in two World Cups' time you can develop that into 12 to 15 really strong, competitive teams, that would be great for the game of rugby."

Fellow Land Rover ambassador Hogg, who was part of the Scotland squad that toured Japan in 2016, said the experience would hold the Scots in good stead off the field.

"We were fortunate to stay in some very good hotels and had some cracking food on offer," he told me by phone from Scotland.

"So we have a rough idea of what we need as professional players, and the (team) nutritionist will also have things sorted, so it's just a case of us fueling up and going out and performing."

And as far as the playing side goes, Hogg said he was not making too much of Japan coach Jamie Joseph's decision to rest a number of players during the ongoing Super Rugby season.

"It's each to their own and Japan will be wanting the best for their players," he said. "If you can keep everyone fit and have a good preseason then they will put themselves in the best possible position."

And that is something that he hopes applies to his own side as well.

"We've been very fortunate to probably pick the best squad we have in a long, long time," he said.

Scotland meets Japan on Oct. 13 at Yokohama International Stadium in the final game of Pool A, a group that also includes Ireland, Russia and Samoa.

Wales, meanwhile, has been drawn in Pool D alongside Australia, Georgia, Fiji and Uruguay, and Warburton believes the 14-game winning streak the team is currently on should see them go far in the tournament.

"It does help massively. I've gone into World Cups where we've had a poor Six Nations campaigns and vice versa but it's so much easier when you have wins under your belt."

Rich Freeman writes about rugby for Kyodo News and can be heard talking about it during Sunwolves' home games.