(Corrects Medvedeva's win in paragraph 20 to Russian Cup, not Russian nationals)
By Elaine Lies
TOKYO, March 15 (Reuters) - A figure skating showdown between Olympic gold medallist Yuzuru Hanyu and reigning world champion Nathan Chen is set to dominate next week's world championships in Saitama as the two face off for the first time in over a year.
Hanyu, who has aggravated a right ankle injury, was forced to drop out of last year's Japan nationals and the Grand Prix Final, where Chen claimed the crown for a second year running, meaning they have not competed against each other since the 2018 Winter Olympics in Pyeongchang.
There, Chen bombed out of the short programme in 17th place but skated an incredible free with five clean quad jumps that catapulted him to fifth.
Japan's Hanyu, skating on painkillers after injuring his ankle in a practice fall, became the first man in over 50 years to win back-to-back Olympic figure skating gold medals.
Though juggling practice and classes as a Yale University freshman, the 19-year-old Chen became U.S. champion for the third straight year in January with a powerful free skate.
"Worlds is a whole other ballgame," Chen said at the time.
"I'm really excited for it. I'm going to start training as best as I can for it."
Hanyu has not competed since last November when he won the Rostelecom Cup with the biggest point spread ever, but coach Brian Orser said the 24-year-old was determined to perform at his peak on home ice.
"He is a good, strong competitor and the worlds are in Japan, so he wants to be on top form," Orser told reporters at the European championships in January.
Hanyu has another incentive - the arena in Saitama, just north of Tokyo, is where he won the first of his two world titles in 2014.
The pair face a challenge from Japan's Shoma Uno, who grabbed Grand Prix silver for the second year in a row and took gold at the Four Continents meet in February with a record-breaking free skate score under new rules in effect this season.
"I told myself that I could do it and skated without thinking about anything," said the soft-spoken 21-year-old, who won silver at Pyeongchang and has spent his career in the shadow of the charismatic Hanyu.
With 2018 champion Kaetlyn Osmond of Canada sitting out the season, the race for the ladies title is wide open.
Olympic champion Alina Zagitova will be seeking to atone for the 2018 worlds when the 16-year-old fell three times in her free skate and finished fifth overall, the Russian's only loss of the 2017-2018 season.
But a growth spurt last year and an uneven season, which saw her finish second in the Grand Prix Final despite topping the podium in both her Grand Prix events and holding four world records under the new point system, means victory is far from certain.
Zagitova's major challenge is likely to come from Japanese 16-year-old Rika Kihira, whose increasingly consistent jumps, including the triple axel, saw her win a surprise gold at the Grand Prix Final and then another at the Four Continents.
Kihira's season has also seen some wobbles, however, as foot problems saw her take just silver at the Japan nationals.
Also likely to be in the mix is two-times world champion Evgenia Medvedeva, who sat out the meet last year due to a foot stress fracture that hampered much of her 2017-2018 season.
The 19-year-old, who was denied gold in Pyeongchang by compatriot Zagitova, took the highly unusual step for a Russian skater last year in leaving home to train with Orser in Canada.
She has struggled this season and even replaced her short programme halfway through. But in February she topped the podium at the Russian Cup, winning a berth for the worlds.
In ice dancing, French team Gabriella Papadakis and Guillaume Cizeron, who narrowly lost out on Olympic gold in Pyeongchang after a clasp on Papadakis's costume came undone, have had an uneven season due to Cizeron suffering a back injury.
However, they came back strong to claim gold in the European Championships and set a world record.
They face competition from U.S. team Madison Hubbell and Zachary Donohue, who won the Grand Prix Final.
The World Figure Skating Championships run from March 18 to 24. (Editing by Peter Rutherford )