Mountain Freestone · Volcanic · Honshū, JP

Azusa River (Kamikōchi)

Japan Alps river
Poor · Rainbow Trout
Parachute Adams / olive · 14–18
Not the day for it
River lifting fast on the rain. Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
45% confidence
limited data
What moved it
  • LevelVery heavy rain recentlyNo gauge reading
  • Water temp5.5°C
  • ClarityUnfishable
Today's fly
Parachute Adams / olive
Parachute Adams / olive14–18
Proven pattern for this period
Conditions on the water
Estimate
Level
Very heavy rain recently
No gauge reading
Water temp5.5°C
ClarityUnfishable
Weather10°C
WindNW 4 km/h
Pressure1013 hPa
Rain · recent58.3 mm
Rain · ahead4.8 mm

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

Water temperature for Rainbow Trout
Cool — slow
6°C est.ideal 10–18°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
Poor — barometric pressure is working for you, but water clarity is the limiting factor today.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 2 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Supporters see what else is on the menu.

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Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · October highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Stenopsyche CaddisHatch
2
3
3
2
Cicada (Semi)Hatch
2
2
Ephemera strigata (Mid-Reach Keiryu Mayfly)Hatch
2
3
3
3
2
Epeorus latifolium (Riffle Mayfly)Hatch
2
3
3
3
3
3
2

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

Ranked for today
Fly box · Rainbow Trout
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
Fishing better nearby · 1
Kiso River (upper / Kiso Valley)
50 km
52
White spotted char · Amago · Rainbow trout
Gallery · 2
  1. Japan Alps river
    Alpine river through UNESCO-protected Kamikōchi.
  2. Terrain map of the venue
    Terrain map
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 45%
How the 20 is built — score × weight = contribution
Temperature29 × 28%8.1
Flow28 × 22%6.2
Clarity10 × 18%1.8
Feeding Time40 × 13%5.2
Pressure75 × 7%5.3
Insect activity37 × 12%4.4
Limiting factor: Water is unfishable — too coloured for Rainbow Trout= 31
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Warmer water — toward the 10–18 °C ideal band — would lift the temperature score.
A drop and clear would lift the flow and clarity scores.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Char late February to April → late 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
Euro Nymphingsubsurface methods
Booking & contacts