Uno (24), already in the lead after the short program, won with a total of 312.48 points, a new personal best.
He beat his young compatriot Yuma Kagiyama (297.60), 18 and Olympic silver medalist in February, already outgoing world vice-champion, and American Vincent Zhou (277.38).
Like Chen, who suffers from a "lingering injury" that has remained mysterious, Japanese icon Yuzuru Hanyu, recalcitrant right ankle, was absent.
“I am finally the first,” appreciated Uno, a recent Olympic bronze medalist.
But it is above all his trainer since 2019, the Swiss Stéphane Lambiel, double world champion (2005 and 2006) and 2006 Olympic vice-champion, who has given free rein to his joy.
Accustomed to international podiums since 2017 - Olympic silver and bronze in 2018 and 2022, world silver in 2017 and 2018, the Japanese skater had never before climbed to the highest step on the planetary level.
He achieved this after a performance on Ravel's Boléro during which he attempted five quadruple jumps.
In his quest for world gold, a year after silver, and a month after Olympic silver, Kagiyama paid dearly for his triple Axel turned singles, plus one of his four "quads" demoted to triple jump .
For Zhou, the bronze is worth revenge: the 21-year-old American had been deprived by the Covid-19 of an individual event at the Beijing Games.
This is his second world medal, the second in bronze, after 2019.
On the French side, satisfaction for Adam Siao Him Fa. For his first Worlds, and after an already convincing free program, the 21-year-old skater made his way into the top 10, in eighth place, after a solid program free to the sound of Daft Punk, with a personal best improved by more than fifteen points (266.12 against 250.15).
In difficulty on his short program, and despite another imperfect performance on Saturday afternoon, Kevin Aymoz ranked eleventh (245.46).
Two combined results that offer French skating two places in the men's category for the international championships next winter.
© 2022 AFP