With a year to go until the Paris Olympics, swimming's top stars are aiming to make a splash at the world championships starting Sunday in the Japanese city of Fukuoka.
Serial winners like American Katie Ledecky and Australian Ariarne Titmus will be joined by a new generation of champions including Canadian teen Summer McIntosh and France's Leon Marchand.
But several of the sport's biggest names will not compete for reasons ranging from mental health to sputtering form, with American Caeleb Dressel, Britain's Adam Peaty and Hungary's Kristof Milak all absent.
Fukuoka's hosting of the world championships has been postponed twice because of the Covid pandemic, and comes hot on the heels of an extra edition of the competition in Budapest last year.
The next worlds will take place in Doha in February next year, and with the Paris Olympics looming just beyond that, the world's top swimmers are keen to lay down a marker over the coming week.
"I'm loving it and so happy doing this," Australia's Kyle Chalmers, who is expected to battle Romanian star David Popovici for the men's 100m freestyle title, said last month.
"I can't wait to get on the world stage."
The competition begins with a blockbuster opening night, with Ledecky, Titmus and McIntosh set to do battle in the women's 400m freestyle.
Ledecky is the defending world champion and Titmus holds the Olympic crown, but 16-year-old McIntosh threw down the gauntlet by breaking Titmus's world record in March in a time of 3 min, 56.08 sec.
Titmus has added a little spice to the showdown by questioning McIntosh's credentials, suggesting she lacks experience "on the international stage with the big pressure".
McIntosh could be one of the stars of the championships, having also claimed the 400m individual medley world record this year, just days after breaking the 400 freestyle mark.
Later the same evening, Marchand will compete in the men's 400m individual medley.
He has been tipped to take a serious crack at Michael Phelps's world record of 4 min, 03.84 sec -- a mark which has stood since the 2008 Beijing Olympics.
Marchand is likely to be one of the faces of the Paris Olympics, and he and Popovici are expected to provide the stardust in the men's field in Fukuoka in the absence of a host of established names.
Butterfly king Milak, who won two golds on home turf last year, withdrew saying he was "neither physically nor mentally in a position to be among the best in the world".
Peaty, an eight-time world champion and three-time Olympic gold medallist in breaststroke, is taking a mental health break after falling into a "self-destructive spiral".
Dressel, meanwhile, failed to qualify at the US trials earlier this month.
The seven-time Olympic gold medallist pulled out of last year's worlds citing unspecified medical concerns, and his comeback bid came up short in all four events he entered.
Twice Olympic gold-medallist Simone Manuel will skip Fukuoka to concentrate on the Paris Games but the women's field is otherwise strong.
Australia's Emma McKeon, who won seven medals at the Tokyo Olympics, will go for more gold in the sprint events.
Compatriot Kaylee McKeown will square off against Americans Regan Smith and Katharine Berkoff in backstroke, while versatile American Kate Douglass will compete in freestyle, breaststroke and individual medley.
Australia's Mollie O'Callaghan could also make a huge splash, having upset Olympic champion Titmus in the 200m freestyle last month and looking capable of winning other events too.
Then there is Ledecky, who is the red-hot favourite to win a record sixth 800m freestyle gold and add to her haul of 22 world championship medals -- also a record for a woman.
The 26-year-old is also strongly fancied in the 1,500m, a race in which she owns the top 15 fastest times ever.
On the men's side, Australian 200m breaststroke world record holder and world and Olympic champion Zac Stubblety-Cook will look for more glory, while compatriot Cameron McEvoy is aiming to cap a comeback in the 50m freestyle.
China will be hoping for a better showing than last year in Budapest, where Yang Junxuan won their only individual gold in the pool, in the women's 200m freestyle.
Russia, meanwhile, have again been banned along with Belarus over the war in Ukraine.
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