Perfect platform for Brave Blossoms to show they are new force in rugby
It was a victory that still stands alone as the biggest upset in World Cup history, and now, four years after stunning South Africa, Japan are ready to show why that unforgettable result was the start of something even bigger.
They are not shy in publicly saying so either, as the Brave Blossoms' captain Michael Leitch declared earlier this year that his side want to win the World Cup.
As Leitch admitted, it was an "outrageous statement", but he has seen enough development over the last few years to suggest that Japan can exceed expectations in front of their home crowd.
Although it is still very much a minority sport in Japan, rugby is growing and with an influx of foreign players as well as coaches, the standard across the board has naturally been steadily increasing.
Back in 2015, Eddie Jones worked miracles with a team who somehow managed to topple the Springboks.
After Jones left for England, Japan made another shrewd head coach appointment in former All Black Jamie Joseph, who also won nine caps for Japan.
A hugely respected figure in the game, Joseph has a deep understanding of the Japanese culture and he knows how to get the best out of his players.
"We want to make the top eight, we think we can do that," Joseph insisted.
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The 49-year-old enjoyed great success with the Highlanders across a six-year spell in Super Rugby, and the locals in Japan firmly believe that something special is again on the cards over the coming weeks.
The introduction of the Sunwolves to Super Rugby certainly helped their cause, despite uncertainty surrounding the club's future.
Along with Tony Brown, another highly-regarded Kiwi rugby brain, Joseph has worked closely with the Sunwolves, who include the majority of the national team in their ranks.
Super Rugby very much took a back seat this year as the attention focused on the World Cup.
It was no surprise, then, that Joseph assembled his squad throughout the season for mini camps as he looked to make use of every possible window.
As every other nation has done, Ireland included, Japan have utilised World Cup's residency rules, which means that they have included several overseas players in their squad.
The last four years have been all about building that squad depth and they now arrive at tomorrow's opener against Russia in good nick.
Since 2015, Japan have played 30 games and won 18 of them. Admittedly, most of those were against lesser nations, but their draw against France in 2017 was another reminder of what they are capable of on their day.
Joseph's men will come into the tournament buoyed by having ended their five-year wait to win the Pacific Nations Cup - a competition that Joe Schmidt kept a very close eye on.
"The Japanese are very strong," the Ireland head coach warned.
"I was really impressed with them in the Pacific Nations Cup. Three victories from three performances against really good teams.
"I think they've got a variety to their game as well. Yu Tamura is playing exceptionally well, with guys like (Kotaro) Matsushima and (Kenki) Fukuoka on the edges. They're incredibly dangerous.
"And with Michael Leitch leading their front line, yeah, I think they are going to be a really difficult task for us.
"We saw what they did in the last World Cup, and people were saying it was an upset against South Africa. Well, maybe it doesn't become an upset any more.
"There's an expectation now, more than an upset, that they can compete with whoever they play.
"They'll have an eight-day turnaround when they play us, after playing Russia.
"We play Scotland two days later so we'll be going to Shizuoka on the back of a six-day turnaround. So that will probably complicate things just a little but for us as well."
The opening game between the hosts and Russia may not be the most glamorous fixture, but it gives Japan an ideal chance to get their tournament off to a winning start and with it, ensure that the entire nation is behind them as they roll into the second round clash against Ireland.
Greg Feek, Ireland's scrum coach, also understands what this World Cup means to the people of Japan, having taken on a role as an assistant coach at Japanese league club NEC Green Rockets.
The former All Black, who will end his nine-year stay in Ireland following the tournament, echoed Schmidt's sentiments about the threat that the Brave Blossoms will pose.
"A lot of their players have excellent footwork and it is hard to defend at times. Their half-backs like to have a crack as well.
"They are quite quick to play off the ground, you can see their style of play, it is to keep as many numbers off the ground as you can, less numbers in rucks and speed of ball.
"Now they have brought in a few variants in set-piece attack, the kicking game which can be an issue over there with the humidity, so there is some exciting things for them."
That excitement has been building for years and now that their moment has arrived, Japan will be doing everything they can to prove why they are one of the coming forces in world rugby.