Aki Kuroda got the Japanese off to the perfect start in the women's under-78 kilograms competition as she saw off the challenge from Brazil's Beatriz Freitas.

Despite being a reigning continental champion, Freitas was unable to stop Kuroda from taking the lead with a clear uchi-mata before sealing an ippon victory.

Uzbekistan's Iriskhon Kurbanbaeva triumphed against France's Oceane Zatchi Bi in the first bronze-medal match while Lieke Derks of The Netherlands secured the other against Chinese Taipei's Yu Sin-Yi.

Mao Arai continued Japan's success in the women's over-78kg final against Turkey's Hilal Ozturk with a clinical hip toss for the ippon.

Another Japanese medal came courtesy of Miki Mukunoki as she shared third on the podium with Italy's Erica Simonetti.

The men's over-100kg decider saw the third and final Japanese gold as Yuta Nakamura defeated Cruz Leon Omar of Cuba.

The bout was a cagey affair for the regulation four minutes but an uchi-mata ippon for Nakamura ensured he prevailed in the golden score.

Islombek Ravshankulov of Uzbekistan and Georgian Shalva Gureshidze managed to seal bronze medals against American Christian Konoval and Dutchman Jules Blom, respectively.

Nakamura's gold medal is Japan's sixth of the 21-and-younger event.

France's Kenny Liveze denied Japan a monopoly of gold medals on the day as he defeated Tomihori Nakano in the men's under-100kg class.

It took just 30 seconds for Liveze throw his opponent flat on his back for the ippon with a yoko-sutemi-waza.

Germany's Kilian Kappelmeier and Benjamin Mataseje of Slovakia made up the podium with the bronze medals.

The event is set to conclude tomorrow with the mixed team competition.