Germany's Annika Schleu took the lead in the women's event, while Great Britain's Joseph Choong shared the lead with the ROC's Alexander Lifanov in the men's event Thursday on the first day of modern pentathlon competition at the Tokyo Olympics.
In the revised pentathlon format, the head-to-head round-robin fencing competition takes place a day before the rest of the events, with a fencing "bonus round" included along with shooting, horse riding and the run/shoot phases on the next day. The bonus round gives athletes a chance to make up some points, with the lowest-ranked competitors facing off and the winner facing the next-lowest, that winner facing the next-lowest after that, and so on. Each win is worth a point except the final bout, which is worth two.
Schleu, who finished fourth in the 2016 Olympics, won 29 of her 35 bouts for 274 points, 30 points ahead of South Korea's Kim Se-Hee.
In the men's event, Choong and Lifanov each had 25-10 records for 250 points, with many others tightly bunched behind them.
Neither gold medalist from Rio is currently competing.
The rest of the women's competition takes place on Friday. The men's event is Saturday.