17-Yr-Old Raito Numata Posts 3:46.11 Lifetime Best In 400 Free At JPN Championships

102nd JAPAN SWIMMING CHAMPIONSHIPS

• Thursday, June 4th – Sunday, June 7th
• Tokyo Aquatics Centre
• LCM (50m)
• SwimSwam Preview
• Meet Central
• Entries
• Live Results

The 102nd Japan Swimming Championships saw its first day of action get underway from the Tokyo Aquatics Centre, with the nation’s athletes vying for potential remaining slots on the Pan Pacific Championships roster.

We reported how 20-year-old Yamato Okadome broke through in a big way, firing off a new lifetime best in the men’s 100m breaststroke on his way to victory.

In the heats of the event, the Cal Bear cleared the minute barrier for his first time ever, clocking 59.44. He followed that up with a blistering 59.11 to grab the gold ahead of two-time World Junior record holder Shin Ohashi.

You can read more about the men’s 100m breaststroke final here.

The final of the men’s 400m freestyle also saw its victor establish a new lifetime best, as Raito Numata turned in a speedy effort of 3:46.11 to get to the wall first.

That edged out the competition by just under a second, with Asaki Nishikawa settling for silver in 3:47.10, followed by Maki Kiriyama who rounded out the podium in 3:49.48.

Entering this competition, Numata’s career-quickest time checked in at the 3:47.26 he logged at the 2025 Japanese Sports Festival last September as a 16-year-old.

Now 17 years of age, Numata becomes Japan’s 6th-fastest 400m freestyler in history, with four of those men clocking their bests just this year.

Top Six Japanese Men’s LCM 400 Freestyle Performers All-Time

1. Kosuke Hagino – 3:43.90, 2014
2. Takeshi Matsuda – 3:44.99, 2008
3. Kazushi Imafuku – 3:45.84, 2026 & Tatsuya Murasa – 3:45.84, 2026
4. –
5. Asaki Nishikawa – 3:46.04, 2026
6. Raito Numata – 3:46.11, 2026

For perspective, Numata would rank as the United States’ 5th-best 17-and-18-year-old boy of all time. He now ranks 15th in the world at the moment.

As a refresher, the teen captured five medals at the 2025 World Junior Championships including gold in the 400m IM and gold in the men’s 4x100m free relay. He also earned silver in the men’s 4x200m free relay, bronze in the 200m free and bronze in the 200m IM events.

On the women’s side of the house, Ichika Kajimoto, the 22-year-old world champion in the 3k open water knockout sprints, proved too quick to catch in the 400m free.

Kajimoto notched a time of 4:08.14 to comfortably defeat the pack, with the next-closest swimmer represented by Waka Kobori who nabbed silver in 4:09.38.

Rika Okumura was the bronze medalist in 4:10.40.

Kajimoto and Kobori already rank within the top 5 Japanese women’s 400m freestyle all-time list. Kobori’s lifetime best of 4:05.57 from the 2020 Olympic Games ranks her 3rd, while Kajimoto’s 4:06.61 from a couple of months ago checks her in as Japan’s #4 performer.

University of Tennessee’s Mizuki Hirai tried her signature 100m butterfly on for size, putting up a solid result of 57.60.

The 19-year-old opened in 26.99 and closed in 30.61 to come within range of her season-best 56.70 clocked last September to rank 4th in the world right now.

Three-time Olympian Rikako Ikee touched in 58.11 as the runner-up and fellow Olympian Nagisa Ikemoto rounded out the medalists in 59.03.

We reported late last year that, after several years at Griffith University in Australia, 25-year-old Ikee returned home to continue her training in Japan in the leadup to the 2028 Olympic Games.

World Championships medalist Mio Narita got the job done in the women’s 200m IM, posting 2:10.25 as the decisive victor.

Mana Ishikawa turned in a time of 2:11.88 for silver and Shuna Sasaki bagged the bronze in 2:11.97.

It’s important to note that all three of these athletes are only teenagers, giving Japan a potentially damaging stable of IMers. Narita is 19, Ishikawa is 17 and Sasaki is just 16 years of age.

Sasaki is already an experienced international medalist. The teen earned bronze in both the 200m IM and 400m IM at the 2025 World Junior Championships and before that claimed 400m IM bronze at the 2024 Junior Pan Pacific Championships.

Additional Notes

• There was a tie in the men’s 50m butterfly final this evening, as Taikan Tanaka and Shoon Mitsunaga both hit the wall simultaneously in 23.28. Tomonobu Gomi was immediately behind in 23.36, good enough for bronze. Tanaka and Mitsunaga have a habit of turning in the same times – they share the 23.06 national record the former produced last year and the latter matched this past March. As a refresher, Mitsunaga is coming off a 4-month suspension for having testing positively for a banned substance.
• The men’s 100m back saw Hidekazu Takehara grab the gold, hitting a mark of 53.85. That was just a hair off his lifetime best of 53.63 put up at March’s Japan Swim. Yumeki Kojima, the 17-year-old World Junior record holder of both the 200m IM and 400m IM, snagged silver in 53.98. That checked in as the teen’s first outing ever under the 54-second barrier, knocking down the 54.05 he produced at the Japanese Sports Festival last September. He now moves up one spot to tie Olympic medalist Daiya Seto as the 15th-fastest Japanese performer of all time. Kodai Nishiono captured the bronze this evening in 54.28.
• Miri Sasaki topped the podium in the women’s edition of the 100m backstroke, clocking an effort of 1:00.25. Rio Shirai was next to the wall in 1:00.37, followed by Kyoka Sawa who hit 1:00.67 for the bronze. This continues to be a struggle for the Japanese women and will continue to impact their medley relay chances if they don’t find their missing backstroke piece. We’ll see how this impacts the squad at this year’s Asian Games.