Host Japan got off to a perfect start at the Tokyo Grand Slam on Friday, winning all five divisions contested on the first day at Tokyo Metropolitan Gymnasium.
Naohisa Takato beat South Korea's Kim Won-jin in the men's 60-kg final by ippon. It was the second straight title here for the 20-year-old world champion, who is nursing a shoulder injury.
"I can't say it hurts," Takato said. "At long last, I fought like a champion."
In the men's 66-kg division, Japan's Tomofumi Takajo won his first Tokyo title in two years.
High school student Ami Kondo had a day to remember in the women's 48-kg category. The 18-year-old defeated London Olympic champion Sarah Menezes of Brazil in the semifinals before taking the gold with a victory in the final over Mongolian world champion Urantsetseg Munkhbat. Both victories came by ippon.
"It was my debut in the tournament, so I went all out," Kondo said. "Winning by ippon is what my judo is all about."
World bronze medalist Yuki Hashimoto defended her 52-kg crown after winning all four of her matches by ippon, while Nae Udaka won the 57-kg title for the first time.