The tournament promises to be one of the most open in history, with at least five or six teams capable of preventing favourites New Zealand from winning an unprecedented third consecutive title.
Organisers hope stars of the game such as All Black Beauden Barrett, Ireland's Johnny Sexton or South Africa's Siya Kolisi will spark enthusiasm for the game in Japan and Asia more broadly.
The early signs are good, with officials saying the tournament should be close to a complete sell-out and a staggering 15,000 fans turning out on a public holiday just to watch Wales train.
The global rugby showpiece will also serve as a tasty amuse-bouche for Japan as it prepares to host the Tokyo 2020 Summer Olympics.
World Rugby Chairman Bill Beaumont said they had awarded the tournament to Japan in the hope it would be "a powerful game-changer for sporting and social change in Asia, the world's most populous and youthful continent".
Officials claim that a promotional drive has inspired 1.8 million new rugby participants since 2016, one million of those in Japan.
But there are also reasons to believe the game in Japan is in need of support, with declining gates for club rugby matches and the country's only Super Rugby franchise, the Tokyo-based Sunwolves, booted out of the competition for commercial and logistical reasons.
- 'Mythical dawn of time' -
Much will depend on the success of the home team, which gets the tournament underway on Friday with what should be a routine win against Russia.
Japan served up the biggest shock in World Cup history in 2015 when they beat the mighty Springboks 34-32 in a match dubbed the "miracle of Brighton" that has even inspired a movie.
This time, however, no one is taking the Brave Blossoms lightly and they will do well to achieve their goal of reaching their first ever quarter-final by getting out of a pool dominated by Ireland and Scotland.
The All Blacks remain the team to beat and their crunch encounter with South Africa on Saturday will go a long way to determining the outcome of Pool B -- and maybe the next home of the Webb Ellis Cup.
Ireland come into the competition as the world's number one side but often flatter to deceive when it comes to the World Cup and have never ventured beyond the quarter-finals.
Much rests on the shoulders of fly-half Sexton who at 34 is no longer in the first flush of youth and has suffered an alarming dip in form.
England, coached by Eddie Jones -- who led Japan to that famous win over the Springboks -- will also fancy their chances but have been drawn in a tough Pool C alongside bitter Six Nations rivals France and the ever-dangerous Argentina.
The other group sees Australia and Wales as the top teams and either one could trouble the business end of the competition.
But the gap between the traditional haves and have-nots of World Rugby has shrunk and more upsets are expected -- with Fiji in particular considered a dangerous dark horse.
The six-week festival of rugby will get underway with what Beaumont promised would be a "spectacular" opening ceremony with seats ranging from 50,000 to 15,000 yen ($450 to $150).
The ceremony will feature a fly-past by the Blue Impulse formation flying squadron and will draw on "deeply symbolic Japanese cultural references" to "tell the story of the mythical dawn of time, rugby's origins and its arrival in Japan".
With the tournament held in natural disaster-prone Japan, organisers say they have put in a "meticulous" contingency plan against earthquakes and also typhoons, which are very much in season during the competition.
If a match cannot be played, it will count as a draw, resulting in the intriguing potential scoreline of New Zealand 0, Namibia 0.