OSJ KOUMI 100 2026
Also known as: KOUMI100
A 100-miler made of five laps on a course between Lake Matsubara and Inagoyu on the eastern foot of the Yatsugatake range. Between laps runners refuel from their own car or tent at the venue, and a pacer may join from the fourth lap.
The course tops out at 2,178 m (low point 1,157 m). 5 climbs of 600 m or more keep coming; the biggest is 1,021 m around 35–50 km. About 30% of the distance is gentle (under 5% grade). In 2025, 46% of starters finished — a tough one. The median finish was about 33 h, through one night.
Predict your finish from your ITRA index
Enter your ITRA performance index to get your finish time, aid-station splits and cutoff margins from the results of 63 finishers of this race — the same model as the TRAIL STATUS app. Nothing is saved or sent.
The app adds predictions from your training log (Strava), race-day pacing and more. Free, no sign-up.
Predict in detail from my Strava trainingOverview
- Date
- Sun, 11 Oct 2026
- Start
- 07:00
- Location
- Nagano, Japan
- Distance
- 165 km
- Elevation gain
- 7,100 m
- Time limit
- 36h
- ITRA
- 100M
- Official website
- www.outdoorsportsjapan.com/trail/koumi100/race-koumi100
Elevation profile
Aid stations and cutoffs
| # | Distance | Aid station | Segment | Cutoff |
|---|---|---|---|---|
| 1 | 9.5 km | Aid 11周目 A1 本沢 | 9.5 km | — |
| 2 | 13.1 km | Aid 21周目 A2 稲子湯前 | 3.6 km | — |
| 3 | 23.3 km | Aid 31周目 A3 稲子湯前 | 10.2 km | — |
| 4 | 27 km | Aid 41周目 A4 本沢 | 3.7 km | — |
| 5 | 33 km | Aid 51周目終了 松原湖高原スケートセンター（メイン会場・サポート可） | 6 km | — |
| 6 | 42.5 km | Aid 62周目 A1 本沢 | 9.5 km | — |
| 7 | 46.1 km | Aid 72周目 A2 稲子湯前 | 3.6 km | — |
| 8 | 56.3 km | Aid 82周目 A3 稲子湯前 | 10.2 km | — |
| 9 | 60 km | Aid 92周目 A4 本沢 | 3.7 km | — |
| 10 | 66 km | Aid 102周目終了 松原湖高原スケートセンター（メイン会場・サポート可） | 6 km | — |
| 11 | 75.5 km | Aid 113周目 A1 本沢 | 9.5 km | — |
| 12 | 79.1 km | Aid 123周目 A2 稲子湯前 | 3.6 km | — |
| 13 | 89.3 km | Aid 133周目 A3 稲子湯前 | 10.2 km | — |
| 14 | 93 km | Aid 143周目 A4 本沢 | 3.7 km | — |
| 15 | 99 km | Aid 153周目終了 松原湖高原スケートセンター（メイン会場・サポート可） | 6 km | — |
| 16 | 108.5 km | Aid 164周目 A1 本沢 | 9.5 km | — |
| 17 | 112.1 km | Aid 174周目 A2 稲子湯前 | 3.6 km | — |
| 18 | 122.3 km | Aid 184周目 A3 稲子湯前 | 10.2 km | — |
| 19 | 126 km | Aid 194周目 A4 本沢 | 3.7 km | — |
| 20 | 132 km | Aid 204周目終了 松原湖高原スケートセンター（メイン会場・サポート可） | 6 km | Day 2 11:0028h |
| 21 | 141.5 km | Aid 215周目 A1 本沢 | 9.5 km | — |
| 22 | 145.1 km | Aid 225周目 A2 稲子湯前 | 3.6 km | — |
| 23 | 155.3 km | Aid 235周目 A3 稲子湯前 | 10.2 km | — |
| 24 | 159 km | Aid 245周目 A4 本沢 | 3.7 km | — |
| F | 165 km | FinishFINISH 松原湖高原スケートセンター | 6 km | Day 2 19:0036h |
The small figure under each cutoff is the time from the start. Day 1 is the day of the start.
Registration
- Registration
- Tue, 26 May 2026 – Mon, 14 Sep 2026
- Entry
- First come, first served
Add the race in the app to put registration opening and closing and the lottery results into your calendar.
2025 results
270 starters, 123 finishers (45.6% finish rate). Finish times of those who finished:
- Fastest
- 23h 40m
- Top 10%
- 28h 48m
- Top 25%
- 30h 45m
- Median
- 33h 5m
- Top 75%
- 34h 26m
- Top 90%
- 35h 18m
- Last finisher
- 35h 50m
"Top 25%" means one in four finishers had crossed the line by this time.
Years with a different course or different cutoffs are not directly comparable.
Practice courses
See the course on the Runnable map ↗
Runnable has practice courses on this race's trails, split into sections to run and sections to walk (pages in Japanese).
- Runnable practice course (33.6 km)
Other races
- Shinetsu Five Mountains 100mile 2026Mon, 21 Sep 2026 · Nagano, Japan · 163 km
- Shinetsu Five Mountains 110km 2026Tue, 22 Sep 2026 · Nagano, Japan · 112 km
- NOZAWA 65 km 2026Sun, 19 Jul 2026 · Nagano, Japan · 65 km
- OKUSHINANO 100 100km 2026Sat, 6 Jun 2026 · Nagano, Japan · 100 km
- OSJ ONTAKE100 100K 2026Sun, 19 Jul 2026 · Nagano, Japan · 107 km
- SHIGAKOGEN 100 100km 2026Sat, 29 Aug 2026 · Nagano, Japan · 100 km
From your training log, TRAIL STATUS estimates your finish time, aid-station splits and cutoff margins for this race.
Predict my raceCompiled from each race's official information. Details can change, so always check the race's official website for the latest. Spotted a mistake? Please tell us through the contact form.
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