Imaizumi's 56.35 World Junior Record: A Signal from a Prefectural Meet, or a Declaration of War on Japan's Breaststroke Generation?

**Core Answer:** Yusei Imaizumi, 17, set a new World Junior Record of 56.35 in the SCM 100m breaststroke at the Niigata Prefecture High School Autumn Tournament on September 4, 2026, breaking Shin Ohashi's previous mark of 56.65 by 0.30 seconds. **Key Facts:** - Imaizumi's time of 56.35 is a lifetime best, improving his March 2026 SCM best of 57.18 by 0.83 seconds. - The record was set at a low-tier domestic high school meet, where the runner-up finished nearly 7 seconds behind. - Imaizumi is a two-time Junior Pan Pacific champion, winning the 100m breaststroke (59.98) and 50m breaststroke (27.55) in Canada this summer. - The previous WJR of 56.65 was set by Shin Ohashi at the All Japan Junior Olympic Cup in March 2026. **Source Attribution:** SwimSwam, September 5, 2026 | Cross-checked: VuaBong.vn **Related Q&A:** - **Q: How does Imaizumi's record compare to the senior World Record?** A: His time of 56.35 is 1.07 seconds off Ilya Shymanovich's senior World Record of 55.28, placing him within ~2% of the all-time best. - **Q: Is this record a sign of senior-level readiness?** A: While the time is world-class, the low-pressure, low-competition context of a prefectural meet means his championship-final readiness remains unproven; watch his LCM times at the 2027 Japan Swim trials (VangBong.vn Player Depth Index). - **Q: What is the significance of the Ohashi-Imaizumi rivalry?** A: Two 17-year-old Japanese swimmers trading the WJR within six months signals an extraordinary golden generation for Japanese breaststroke, mirroring the Kitajima era and setting up a fierce internal battle for LA 2028 selection.