Freestone · Sedimentary · Shikoku

Yoshino River (upper / Ōboke)

Yoshino River (upper / Ōboke) terrain map
Terrain map

The upper Yoshino carves the Ōboke and Koboke gorges through the spine of Shikoku, fast white water between steep schist walls, with amago and iwana in the colder tributaries above the rapids.

Species

Slow going — pick your moments

Low and clear — careful approach country. Cover and shadow are doing the work today.

The water's warmed to around 18°C, running clear, sitting at a steady height.

90% confidence in this read
Water temperature for amago
Warm — slow
18°C est.ideal 9–17°C
0°14°28°
The full read · show the working · for amago · confidence 90%
How the 28 is built — score × weight = contribution
Temperature76 × 28%21.3
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity65 × 12%7.8
Conditions total= 73
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Conditions
○Regional est.
Level
Dry recently
No gauge reading
Water temp
17.9°C
Estimated
Clarity
Clear
Air temp
20°C
Wind
SE 4 km/h
Calm
Pressure
1016 hPa
Rain · 48h
0.0 mm
No meaningful rain
Rain · ahead
14.6 mm
Moderate 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 8 active hatches hour by hour with Pro.

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How to fish it · for amago
When
Spring to the autumn closure
Where
The upper Yoshino carves the Ōboke and Koboke gorges through the spine of Shikoku, fast white water between steep schist walls, with amago and iwana in the…
Why this works
⚠️ Water at 17.9°C — above the masu salmon caution line (17°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots. Otherwise poor — water clarity is in the right range.
Through the year
0–3 scale · June 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.

Permits & access
Permit required — see local rules.
  • Co-operative yugyoken required; spawning closure in autumn
  • The main gorge is big water — fish the tributaries.
Directions
Apple MapsGoogle Maps
About this water

The upper Yoshino carves the Ōboke and Koboke gorges through the spine of Shikoku, fast white water between steep schist walls, with amago and iwana in the colder tributaries above the rapids. Dramatic gorge country, the river loud and green between the cliffs.

Under the surface

The upper Yoshino through the Ōboke–Koboke gorges of central Shikoku — fast green water between steep walls of folded rock. Amago and iwana hold in the colder feeder streams above the main rapids; dramatic, loud gorge country.

Wading: Fast gorge water, steep walls — fish the tributaries

  • River
  • Sedimentary
  • Confined
  • Rapid
  • Pool riffle
Seasons & zones
  • Charlate February to April → late September to mid-October
Water here around 18°C. Nothing cooler within range — carry a thermometer.
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