Naohisa Takato won Japan's first gold medal of the 2020 Olympics when he outlasted Yung Wei Yang of Chinese Taipei in the 60kg weight class on Saturday in Tokyo.
Yeldos Smetov of Kazakhstan won one bronze medal while Luka Mkheidze of France claimed the other.
Medals were also awarded in women's extra lightweight judo, where Kosovo's Distria Krasniqi won 1-0 with a late Waza-Ari against silver-winning Tonaki Funa of Japan.
Krasniqi's win was just the second medal ever for Kosovo, while Funa's silver is Japan's 85th in judo.
The bronze medalists are Daria Bilodid of Ukraine and Urantsetseg Munkhbat of Mongolia.