Freestone · Sedimentary · Shikoku, JP

Yoshino River (upper / Ōboke)

Oboke and Yoshino-gawa river
Tomorrow · Slow going — pick your moments
Sakasa kebari
Forecast · Tomorrow
Slow going — pick your moments
Slow going — pick your moments and do not force it.
80% projected
Today's fly
Sakasa kebari
Sakasa kebari
Conditions on the water · Tomorrow
Estimate
Level
Heavy rain recently
No gauge reading
Water temp18.1°C
ClarityClear
Weather24°C
WindN 8 km/h
Pressure1022 hPa
Rain · recent28.4 mm
Rain · ahead1.9 mm

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

Water temperature for Amago
Warm — slow
18°C est.ideal 9–17°C
0°14°28°
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 18°C — above the masu salmon caution line (17°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots.
Hatch timeline · tomorrowPeak at 12h

12h(now) — Heather Fly

Stage: Terrestrials on topApproach: Dry flyActivity: 95%
Also:Glossosoma (Japan)95%Black Gnat68%Isonychia japonica53%
Peak emergence windowWeather boost10 food groups active

Peak activity at 12h — Heather Fly (Heather Fly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 3 as a supporter.

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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 · Amago
EH
Elk Hair / Stenopsyche caddis
12–14 · Sedge
Evening sedge — twitch or dead-drift it as the light goes.
CB
Cicada & beetle terrestrials (midsummer)
10–12 · Terrestrial
Fish it tight to the bank on warm, breezy days.
Permits & access
Permit required — see local rules.
  • Co-operative yugyoken required; spawning closure in autumn
  • The main gorge is big water — fish the tributaries.
What's coming
Plan ahead
5-day outlook
Water here around 18°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Oboke and Yoshino-gawa river
    Dramatic gorge with sheer rocky cliffs.
  2. Terrain map of the venue
    Terrain map
Conservation note

White-spotted char (iwana) and amago in the tributaries.

The full read · show the working · for Amago · confidence 80%
How the 27 is built — score × weight = contribution
Temperature63 × 28%17.6
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time40 × 13%5.2
Pressure80 × 7%5.6
Insect activity53 × 12%6.4
Conditions total= 65
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 9–17 °C ideal band — would lift the score and ease welfare.
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