Fourteen-year-old Natsu Ota became Japan's youngest national modern pentathlon champion on Sunday, with her victory in the women's competition, which was added in 2010.
Ota won swimming and riding and was third after three disciplines, including fencing. In the final event, the laser run, she came from behind to score 1,388 total points at Tochigi Prefecture's Kawachi Sports Park.
She went head-to-head in the laser run with the 2012 London Olympian Shino Yamanaka, beating the 31-year-old by four seconds despite starting 22 seconds behind and taking the lead in the third lap.
"I was determined not to relinquish the lead. It feels great to come first," said a relieved Ota.
But the youngster, who has made an extra effort to improve her riding, said, "There are parts I'm still not satisfied with," as she aims for a spot in the 2024 Paris Olympics.
"I will up my level in all the disciplines," she said. "I want to take part and win the gold medal."
Taishu Sato won the men's event for the first time scoring 1,459 points.