American gymnastic goddess Simone Biles and Japan's national sporting deity Kohei Uchimura begin their quests for Olympic immortality in Tokyo this weekend.

Both have already achieved enough to be considered the greatest gymnasts of all time, but they approach the delayed 2020 Games as hungry as ever to enhance reputations that already stand as tall as nearby Mount Fuji.

Sunday's women's qualification sees Biles set out on the road she hopes will be paved with five gold medals.

Japanese star Kohei Uchimura is counting on the bar to provide him with a golden retirement Japanese star Kohei Uchimura is counting on the bar to provide him with a golden retirement Photo: AFP / CHARLY TRIBALLEAU

She went close to pulling off the unparalleled feat at the last Olympics in Rio.

Her four golds in 2016 matched the record for a woman gymnast, a bronze in the beam the one that got away.

The 24-year-old Ohio-born superstar will be hot favourite with Suni Lee, Jordan Chiles and Grace McCallum to win the US a third consecutive team title next Tuesday.

Two days later Biles will seek to become the first back-to-back winner of the all-around title in over half a century.

Rhys McClenaghan after claiming pommel horse world championship bronze in 2019 Rhys McClenaghan after claiming pommel horse world championship bronze in 2019 Photo: AFP / Lionel BONAVENTURE

Few will bet against that outcome in a discipline where she is undefeated since 2013 -- an era of domination that has delivered 19 world championship golds to go with her Brazilian quartet.

The vault is next, and if the Ariake Gymnastics Centre, empty due to Tokyo's coronavirus restrictions, was full with fans they would all have their hearts in their mouths as she started her run-up.

That's because the millions watching on their televisions and tablets around the world could be treated to a Yurchenko double pike -- a move so devilishly complex and gravity-defying it had never been attempted by a woman in competition until Biles pulled it off this year.

Biles landing the first ever Yurchenko double pike by a woman in Indiana in May Biles landing the first ever Yurchenko double pike by a woman in Indiana in May Photo: GETTY IMAGES NORTH AMERICA / Emilee Chinn

Then she will again be out to rule the floor and conclude unfinished business on the beam.

Asked after an impressive team training run-out on Wednesday when she'd be heading home she replied: "After we finish the job."

History-seeker Simone Biles in training on Thursday History-seeker Simone Biles in training on Thursday Photo: AFP / Loic VENANCE

The Biles that is set to dazzle and amaze again at these pandemic-postponed Games is a more confident version of her 2016 self.

Since Rio she has often led criticism of USA Gymnastics (USAG) and the United States Olympic and Paralympic Committee over their handling of the Larry Nassar sexual abuse scandal. In 2018 she revealed she was among the hundreds of gymnasts who was sexually abused by Nassar.

She also took a long sabbatical, but initial thoughts of retirement after Tokyo may have to be put on ice as her two French coaches are trying to cajole her into one last dance on the Olympic stage in Paris in 2024.

Retirement is very much on the post Tokyo-horizon for Uchimura, the all-around champion in 2012 and 2016 who only scraped into his fourth Games in qualifying.

At 32 and beset by shoulder problems, the man known by his massive fan base as 'King' Kohei is foregoing a tilt at a third all-around crown to focus on the horizontal bar.

After scraping through qualifying to earn his place in the Japan team he was thrilled to be competing on home soil.

"I love it, especially because it's in Japan!" he said after training in midweek.

"This is my fourth Olympics, and this is probably the best one yet."

The 2019 and 2020 world champion Nikita Nagornyy, competing under a neutral banner with Russia serving a doping suspension, heads the list of pretenders to King Kohei's all-around crown.

Uchimura helped Japan to the men's team gold in 2016, with the Russian Olympic Committee team featuring Artur Dalaloyan, recovering from an Achilles tendon tear in April, and China out to stop them following up.

Greece's Eleftherios Petrounias hopes to be a repeat master of the rings in which a medal of any hue would be hugely emotional for France's Samir Ait Said who has battled back from a gut-churning leg break in Brazil.

In Rio, Britain's Max Whitlock swept all before him on the floor and pommel horse, where Ireland's Rhys McClenaghan, will be one of his main challengers.

Biles meanwhile may have a patent out on most of the records in her sport but there's one milestone that is even out of her prodigious reach.

At 46, the remarkable Uzbek gymnast Oksana Chusovitina is taking part in her eighth, and she says with certitude, last, Olympics.