Mountain Freestone · Granite · Honshū

Kiso River (upper / Kiso Valley)

Kiso River (upper / Kiso Valley) terrain map
Terrain map

The upper Kiso runs through the old post-town valley beneath the Central Alps, cypress-forested and steep, a river of the Nakasendō road and of amago and iwana in its cold tributaries.

Species

A proper day on the water

Low and clear — careful approach country. Stay small, stay accurate.

The water's warmed to about 16°C, running clear, sitting at a steady height.

90% confidence in this read
Water temperature for brown trout
Warm — slow
16°C est.ideal 10–16°C
0°14°28°
The full read · show the working · for brown trout · confidence 90%
How the 78 is built — score × weight = contribution
Temperature95 × 28%26.6
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time75 × 13%9.8
Pressure80 × 7%5.6
Insect activity52 × 12%6.2
Conditions total= 79
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Conditions
○Regional est.
Level
Dry recently
No gauge reading
Water temp
16.2°C
Estimated
Clarity
Clear
Air temp
18°C
Wind
SW 11 km/h
Light breeze
Pressure
1013 hPa
Rain · 48h
0.0 mm
No meaningful rain
Rain · ahead
6.0 mm
Light rain · next 48h

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

Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 11 active hatches hour by hour with Pro.

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How to fish it · for brown 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
Good — water temperature is right today, though insect activity could be better.
Through the year
0–3 scale · June highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Alpine RhithrogenaHatch
2
3
3
2
Sculpin / Baitfish (Rivers)Hatch
2
3
3
3
3
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Blue Winged OliveHatch
1
2
2
2
2
1

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

Permits & access
Permit required — see local rules.
  • Co-operative yugyoken required; spawning closure in autumn
  • Confirm reach and method rules.
Directions
Apple MapsGoogle Maps
About this water

The upper Kiso runs through the old post-town valley beneath the Central Alps, cypress-forested and steep, a river of the Nakasendō road and of amago and iwana in its cold tributaries. Granite keiryu with history in every bend — way-stations, packhorse trails and clear mountain water.

Under the surface

A steep granite river through the cypress-clad Kiso Valley under the Central Alps, threading the old Nakasendō post-towns. Amago and iwana hold in the cold tributaries and pockets; history and forest crowd the banks.

Wading: Swift mountain water, slick rock

  • River
  • Granite
  • Confined
  • Pool riffle
  • Pocket water
Seasons & zones
  • Charlate February to April → late September to mid-October
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