Mountain Freestone · Volcanic · Honshū

Azusa River (Kamikōchi)

Japan Alps river

The Azusa rises at the heart of the Japanese Alps at Kamikōchi, a valley of such beauty that it is protected and walked by thousands, and through it the river runs gin-clear over pale stones beneath the Hotaka peaks.

Prime · Rainbow Trout
Cicada (foam semi pattern) · 6-10
Primelive now
About as good as it gets
Low and clear — careful approach country. Take your time — read the water before you cast.
90% confidence
What moved it
  • LevelLight rain recentlyNo gauge reading
  • Water temp17.3°C
  • ClarityClear
Today's fly
CI
Cicada (foam semi pattern)6-10
High-confidence seasonal pick
Conditions on the water
Estimate
Level
Light rain recently
No gauge reading
Water temp17.3°C
ClarityClear
Weather15°C
WindN 3 km/h
Pressure1019 hPa
Rain · recent9.0 mm
Rain · ahead26.4 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for Rainbow Trout
Ideal
17°C est.ideal 1018°C
0°14°28°
How to fish it · for Rainbow Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Why this works
Excellent — water temperature is right today, though time of day could be better.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 9 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · July highlighted
J
F
M
A
M
J
J
A
S
O
N
D
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Kamikōchi is protected; local co-operative rules and a yugyoken apply, with access and method limits
  • Confirm before fishing.
What's coming
Plan ahead
5-day outlook
Other water nearby · 2
Gallery · 2
  1. Japan Alps river
    Alpine river through UNESCO-protected Kamikōchi.
  2. Terrain map of the venue
    Terrain map
About this water

The Azusa rises at the heart of the Japanese Alps at Kamikōchi, a valley of such beauty that it is protected and walked by thousands, and through it the river runs gin-clear over pale stones beneath the Hotaka peaks. It holds iwana and stocked rainbows in cold alpine water, and it is as much a pilgrimage to a landscape as a fishing trip — tenkara country in the truest sense.

Under the surface

A clear alpine river at the roof of Honshū, running off the Hotaka and Yari peaks through the protected valley of Kamikōchi over pale volcanic stone. Iwana hold in the cold pockets; the water is as much sacred landscape as fishery, and the native fixed-line tenkara belongs here.

Wading: Cold alpine water, protected park rules, altitude

  • River
  • Volcanic
  • Confined
  • Pool riffle
  • Pocket water
Conservation note

White-spotted char (iwana), yamame, and stocked rainbow. Iwana and yamame are the wild natives.

The full read · show the working · for Rainbow Trout · confidence 90%
How the 80 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time55 × 13%7.2
Pressure75 × 7%5.3
Insect activity57 × 12%6.8
Conditions total= 80
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Seasons & zones
  • Char late February to Aprillate September to mid-October

    Honshu/Shikoku/Kyushu keiryu are managed by local fishery co-operatives — a yugyoken (day/annual ticket) is required, and most streams close around 30 September / mid-October for spawning. Species are surfaced in prose only (no engine slugs for yamame, amago or iwana). Legal status: guidance_not_permission.

Related guides
Booking & contacts