Semboku, Akita Pref., Japan · Sunday, September 27, 2026

Fixed Distance 100K

Akita Nairiku 100km Marathon

23 days to go
100 km Distance
not publishedn/a Climbing
5.0 est Grit · Challenging

Calculated from 100 km alone — the organiser has not published an elevation profile. Read 5.0 as a floor, not a verdict.

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39.7001° N, 140.7308° E © OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Time limit 13 hours 7:48 min/km average. Firm. Sustained running. Long aid-station stops will cost you. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. Tighter than 88% of 100K races. Measured against 203 races of the same distance. Cut-off calculator →
Field size ~337 Large. Rarely out of sight of another runner.

DUV results for the 2025 edition (100km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, September

Daytime high 23°C
Night low 14°C
Rainfall Showers likely
Daylight 12 h 00 m of light

Regional 2001-2020 average for September — NASA POWER, grid elevation 350 m. Not a forecast.

The Aid Station

Course-specific beta from the community

👟 gear

With trail terrain, choose a shoe with moderate cushioning for optimal performance.

By UltraHub Expert
🥤 nutrition

For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.

By UltraHub Expert

Gear for this race

Chosen for 100 km of trail.

  • Trail Running Shoes 100 km of trail — cushioning that is still there in the last quarter.
  • Race Nutrition Past 100 km the palate quits before the legs do — carry more than one flavour.
  • Hydration Vests Flask capacity for 100 km, without the bounce.
  • Headlamps A 13 h limit puts you out there after dark.
  • Accessories Chafe and blisters end more 100 km races than fitness does.

Salomon

Ultra Glide 4

$159.95 ★★★★★ 4.6

Adidas

Terrex Agravic Speed Ultra

★★★★★ 4.5

Tailwind

Endurance Fuel

All-in-one calorie and electrolyte drink mix. 200 calories per serving.

$25 ★★★★★ 4.8

Salomon

ADV Skin 12

Industry-standard 12L race vest with front flask pockets and minimal bounce.

$180 ★★★★★ 4.8

Nitecore

UT32

Dual-beam trail running headlamp (1100 lumens) with spot and flood beams.

$100 ★★★★★ 4.5

Buff

CoolNet UV+ Multifunctional

UPF 50+ neck gaiter with cooling technology. Desert and sun essential.

$25 ★★★★★ 4.5
All gear guides →

Course Notes

Point-to-point 100km from Kadodate, Semboku City to Takasu, Kitaakita City. A course that runs along the Akita Nairiku Jukan Railway

Similar races

Other 100K trail ultras, closest in distance first.