Freestone · Sedimentary · Honshū, JP

Tama River (upper / Okutama)

Tama River, Mitake Valley
Tomorrow · Not the day for it
Sakasa kebari
Forecast · Tomorrow
Not the day for it
Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
45% projected
Today's fly
Sakasa kebari
Sakasa kebari
Conditions on the water · Tomorrow
Estimate
Level
Light rain recently
No gauge reading
Water temp16.7°C
ClarityUnfishable
Weather19°C
WindN 8 km/h
Pressure1019 hPa
Rain · recent4.1 mm
Rain · ahead0.0 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 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
Excellent — water temperature is right today, though time of day could be better.
Hatch timeline · tomorrowPeak at 18h

12h(now) — Glossosoma (Japan)

Stage: Taking dunsApproach: Dry flyActivity: 63%
Also:Heather Fly54%Reed Smut46%Isonychia japonica40%
Peak emergence windowWeather boost11 food groups active

Peak activity at 18h — Stenopsyche Caddis (Stenopsyche Caddis, Weather boost)

Sub-surface · on the nymphunder the surface

Hatch predictions

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

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 as a supporter.

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14-day free trial. Cancel anytime.

Evidence
Records-basedModerate confidence

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

Through the year
0–3 scale · September 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.
  • Local co-operative yugyoken required (day/annual ticket); managed stocked reaches with method rules
  • Confirm before fishing.
What's coming
Plan ahead
5-day outlook
Gallery · 2
  1. Tama River, Mitake Valley
    Upper Tama at Mitake Valley
  2. Terrain map of the venue
    Terrain map
Conservation note

Stocked rainbow with wild white-spotted char (iwana) and yamame.

The full read · show the working · for Rainbow Trout · confidence 90%
How the 82 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 activity72 × 12%8.6
Conditions total= 82
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
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