Naoki Mizunuma and Takeshi Kawamoto qualified for this summer's Tokyo Olympics in the men's 100-meter butterfly on Friday at Japan's national swimming championships.

Mizunuma won in 51.03 seconds with Kawamoto, the national record holder, another 0.22 back on the penultimate day of the eight-day meet at Tokyo Aquatics Centre, the Tokyo Olympic swimming venue.

Naoki Mizunuma wins the men's 100-meter butterfly at the national championships at Tokyo Aquatics Centre on April 9, 2021. (Kyodo)  

The duo of 18-year-old Miyu Namba and Waka Kobori, who had both already qualified in the women's 400 freestyle, repeated that feat in the 800. Namba, the 400 runner-up by 0.02, pipped Kobori at the wall in the 800 by 0.06, winning in 8:26.61.

Swimmers can earn Olympic spots here by finishing first or second and beating the Japan Swimming Federation's qualifying time.

Anna Konishi, who has qualified for the women's 400 medley relay, won the women's 200-meter backstroke but slowed over the final meters and finished in 2:09.47, missing the qualifying standard by 0.07.

Rikako Ikee, who was diagnosed with leukemia in February 2019, continued her dramatic comeback with the fastest semifinal time, 24.87, in the 50 freestyle. Ikee, who returned to competition last August, has clinched Olympic berths on the 400 medley and 400 freestyle relay teams.

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