Here’s how Inoue and Nakatani measure up ahead of tonight’s main event. The naturally bigger challenger will bring in advantages across height (three inches), reach (one inch) and age (five years). His southpaw stance is also of note given Inoue’s fleeting vulnerability to the counter left. Both came in under the super-bantamweight division limit of 122lb at yesterday’s weigh-in.

Takuma Inoue, Naoya’s younger brother, has just defended his WBC bantamweight title with a 12-round unanimous-decision win over Kazuto Ioka on the undercard. Ioka recovered nicely from a pair of early knockdowns in the second and third rounds, but the outcome was never in doubt – particularly with the open scoring in use. The official scores were 118-108, 119-107 and 120-106.

The 37-year-old Ioka fell short in his bid to win a world title in a fifth different weight class, joining Thomas Hearns, Sugar Ray Leonard, Oscar De La Hoya, Floyd Mayweather Jr, Manny Pacquiao and Terence Crawford, the recently retired American star who is taking in tonight’s fights from ringside.

Welcome to the Tokyo Dome for what’s sure to be an unforgettable occasion in the annals of Japanese sport. Naoya Inoue and Junto Nakatani, two multiple-weight boxing champions with identical 32-0 records, meet tonight at a sold-out stadium in a long-awaited showdown that has been accurately billed as the biggest fight in Japan’s rich boxing history. A crowd of 55,000 fans have packed the Big Egg during the Golden Week holiday with countless more watching in sold-out cinemas across the country.

For Inoue, this is familiar terrain. The 33-year-old undisputed 122lb champion has spent nearly his entire professional life carving through boxing’s weight divisions with a unique cocktail of speed, footwork and concussive power, winning titles at 108lb and 115lb before unifying all four major belts at bantamweight and super-bantamweight in a destructive ascent that has drawn comparisons to Manny Pacquiao. Known as the Monster, he enters tonight’s bout on a run of 28 straight wins in world championship fights and rarely been extended the distance, even if recent outings have offered flickers of vulnerability.

But Nakatani is not just another challenger. Five years younger, naturally bigger and a rangy southpaw, the 28-year-old arrives as perhaps the most dangerous opponent of Inoue’s career. A three-division world champion who has honed his craft in Los Angeles, where he moved from Japan as a teenager to train under Rudy Hernandez, Nakatani brings in physical advantages in height (three inches) and reach (one inch) along with the kind of quiet confidence that has defined his rise.

The stakes extend beyond belts and domestic bragging rights. Both fighters are fixtures in the pound-for-pound conversation, with Inoue at No 2 and Nakatani at No 6 on Ring Magazine’s most recent list. It is rare enough in boxing today for the best to meet at their peak. Rarer still for them to do so on a stage like this.

The fight has been dubbed 「世紀の一戦」 – the “Fight of the Century” – by Japan’s big five sports dailies. Hyperbole is part of boxing’s fundamental grammar. But on nights like this, it can feel justified. Stay with us for live updates, round-by-round coverage and reaction as one of the most anticipated fights of the year unfolds in Tokyo.