Ultra Running Hub Dakeonsen, Nihonmatsu, Fukushima Pref., Japan · Saturday, September 5, 2026
Fixed Distance 50K
OSJ Adatara Trail 50K
Race completed
50 km Distance
not publishedn/a Climbing
2.5 est Grit · Entry level
Calculated from 50 km alone — the organiser has not published an elevation profile. Read 2.5 as a floor, not a verdict.
What the course asks
Time limit 13 hours
15:36 min/km average. Generous. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. More forgiving than 82% of 50K races. Measured against 1087 races of the same distance. Cut-off calculator →
Field size ~220 Large. Rarely out of sight of another runner.
DUV results for the 2025 edition (53.4km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Typical conditions, September
Daylight 12 h 50 m of light
Results history
| Year | Race | Finishers | Men's winner | Women's winner |
|---|---|---|---|---|
| 2025 | 53.4km | 220 | Ryuta Iwai · 07:28:37 | Izumi Tomizawa · 09:04:41 |
| 2024 | 53.4km | 204 | Satoru Suga · 07:13:20 | Itsuko Uemiya · 09:02:19 |
| 2023 | 53.4km | 219 | Yoshiki Toda · 07:50:48 | Tamami Arai · 09:51:09 |
| 2022 | 53.4km | 197 | Satoru Suga · 06:13:00 | Nozomi Hatakeyama · 09:13:39 |
| 2021 | 50km | 140 | Kensuke Yoshimura · 08:11:59 | Chihiro Usui · 10:59:14 |
| 2020 | 50km | 301 | Yuya Kawasaki · 05:33:16 | Takako Takamura · 06:40:39 |
| 2019 | 50km | 233 | Satoru Suga · 07:33:58 | Mikiko Ota · 09:33:07 |
| 2018 | 50km | 248 | Yoshito Yamatani · 08:00:43 | Nawako Aoki · 10:42:28 |
| 2017 | 50km | 147 | Terunobu Kurokawa · 08:05:59 | Syouko Imano · 10:50:41 |
| 2016 | 50km | 228 | Terunobu Kurokawa · 06:35:56 | Eri Kuwahara · 08:07:17 |
The field grew 8% between 2024 (204) and 2025 (220). 10% of the 2025 field were women.
DUV results for the 2025 edition (53.4km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Course notes
- gear With trail terrain, choose a shoe with moderate cushioning for optimal performance.
Gear for this race
Chosen for 50 km of trail.
- Trail Running Shoes 50 km of trail — cushioning that is still there in the last quarter.
- Race Nutrition 50 km of self-supported fuelling between aid stations.
- Hydration Vests Flask capacity for 50 km, without the bounce.
- Headlamps A 13 h limit puts you out there after dark.
- GPS Watches Battery life first — a 50 km day outlasts most full-GPS modes.
Similar races
Other 50K trail ultras, closest in distance first.