Freestone · Sedimentary · Honshū

Tama River (upper / Okutama)

Tama River, Mitake Valley
Poor · Rainbow Trout
Cicada (foam semi pattern) · 6-10
Poorlive now
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.
80% confidence
What moved it
  • LevelVery heavy rain recentlyNo gauge reading
  • Water temp20.0°C
  • ClarityUnfishable
Today's fly
CI
Cicada (foam semi pattern)6-10
High-confidence seasonal pick
Conditions on the water
Estimate
Level
Very heavy rain recently
No gauge reading
Water temp20.0°C
ClarityUnfishable
Weather21°C
WindN 7 km/h
Pressure1009 hPa
Rain · recent93.9 mm
Rain · ahead13.2 mm

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

Water temperature for Rainbow Trout
Warm — slow
20°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
Water at 20°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Evidence
ModelledModerate confidence

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

Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Stenopsyche CaddisHatch
2
3
3
2
Cicada (Semi)Hatch
2
2
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2

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.
  • 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
Water here around 20°C. Nothing cooler within range — carry a thermometer.
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 80%
How the 20 is built — score × weight = contribution
Temperature44 × 28%12.3
Flow15 × 22%3.3
Clarity10 × 18%1.8
Feeding Time80 × 13%10.4
Pressure75 × 7%5.3
Insect activity20 × 12%2.4
Limiting factor: Water is unfishable — too coloured for Rainbow Trout= 36
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–18 °C ideal band — would lift the score and ease welfare.
A drop and clear would lift the flow and clarity scores.
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