Shoma Uno placed top after the men's short program at the Japan national figure skating championships on Friday, 5.49 points ahead of Keiji Tanaka.
Defending champion Uno performed a routine that featured two quadruple jumps for a total score of 96.83 at the competition held in the absence of Sochi Olympic gold medalist Yuzuru Hanyu, who withdrew due to a right ankle injury.
Takahito Mura was third with 85.53 points in the competition that doubles as a qualifier for February's Pyeongchang Olympics.
Uno lost balance slightly after landing a quadruple toe loop -- the first of a planned quad-triple combination jump -- and made a single toe loop instead at Musashino Forest Sport Plaza.
"I had points deducted for my combination jump, where I could've scored more," Uno said. "I'm not satisfied with my score, so I want to do better in my free program."
The winners of the men's and women's competitions at the four-day nationals will be granted berths for the Pyeongchang Olympics. Japan secured three spots in the men's competition and two for women.
In the ice dance, defending champions Kana Muramoto and Chris Reed took the lead after the short dance with 65.71 points. Misato Komatsubara and Tim Koleto were second, and Rikako Fukase and Aru Tateno were third.