Akira Sone remained on course for her dream of progressing toward an Olympic gold medal on Sunday as she captured her second straight Japan women's national judo championship.

The 18-year-old Sone, the reigning Asian Games heavyweight champion, had her back to the wall after receiving the first two "shido" warnings but hung on to beat over-78-kg world champion Sara Asahina on penalties, when Asahina received her third warning in extra time.

"Looking forward to this year's world championships and the 2020 Tokyo Olympics, my goal is to qualify for the Olympics and win a gold medal. I'm going to keep doing my best to achieve that," said Sone, who needed to beat Asahina in the semifinals last year.

"I thought I might have to beat her again, and I'm so glad I was able to do that," she added.

A year ago, Sone became the first judoka to win the championship in her tournament debut and its second-youngest champion.

"When I was penalized, I thought to myself, 'You knew this was not going to be easy,' " Sone said. "It was my fault to receive the warnings, but I was able to gut it out and hang on."