Fly fishing near Nozawa Onsen and Iiyama

16 Mar – 30 Sep
Trout and char seasonIwana, yamame and rainbow trout in the local cooperative's waters
¥800 a day
Day permit¥5,000 for the year · junior-high age and under free · extra if bought on the bank
15 cm
Minimum sizeIwana, yamame and rainbow trout at or under 15 cm go back
All year
Dace, chub and carpNo closed season for ugui, oikawa and koi

These are the published rules of the Kōsui Fisheries Cooperative, which manages the Chikuma River and its tributaries around Iiyama. Other rivers on this page belong to other cooperatives with their own dates and fees. Always check the current rules for the water you are fishing.

Where to fish

Rivers and lakes near the house.

Water	From the house	Character	Main fly targets
Chikuma RiverIiyama	Minutes	Japan's longest river: wide, strong water with riffles, glides and deep pools. Best waded at the edges.	Rainbow trout, ugui, oikawa, smallmouth bass, carp
Taru RiverTarukawa, Kijimadaira	About 20 min	A cold freestone tributary falling from the Shiga highlands, with pocket water and plunge pools.	Iwana, yamame
Maguse RiverKijimadaira	About 20 min	A small, steep mountain stream, tight and shaded, suited to short rods and tenkara.	Iwana, yamame
Kitano RiverSakae	About 30 min	A quiet valley stream on the Niigata border with easy wading and little pressure.	Iwana, yamame
Yomase RiverYamanouchi	About 30 min	A broader, boulder-strewn river below Shiga Kogen with room to cast.	Yamame, iwana, rainbow trout
Seki RiverMyoko	About 45 min	A snowmelt river off Mt Myoko that runs high and cold well into early summer.	Iwana, yamame
Nakatsu RiverAkiyama-gō	An hour or more	A remote gorge river in one of Japan's most isolated valleys. A full-day trip.	Iwana
Zako RiverOku-Shiga	Over an hour	A famous high-country stream of wild, never-stocked iwana. The headwaters are closed to protect them.	Wild iwana only
Lake NojiriShinano-machi	About 40 min	A deep, clear highland lake, best fished from a boat.	Smallmouth bass, largemouth bass

Drive times are rough guides. Snowmelt keeps the streams high and cold from April into June; the smaller tributaries clear first. Tell us your dates and experience when you enquire and we'll suggest where to start.

Species & flies

What lives here, and what it eats.

Rods, line weights and proven patterns for each fish, with hook sizes. Local hatches vary from stream to stream, so treat these as a well-stocked starting box.

Native species

Iwana 岩魚 · white-spotted char

The fish of the headwaters: dark, pale-spotted and bold. Iwana hold in pockets, undercuts and plunge pools and will rise freely to a big dry fly. Typically 18–30 cm, with larger fish in the deep pools.

Rod 7' – 7'6" · #2 – #3
Line Floating, double taper
Leader 7.5 – 9 ft · 5X – 6X
Tenkara 3.3 – 3.6 m rod

Type	Pattern	Hook size	When
Dry	Elk Hair Caddis	#10 – #14	May – Sep, the all-round searching fly
	Royal Wulff / Stimulator	#10 – #12	Fast, broken pocket water
	Parachute Adams	#12 – #16	All season
	Parachute Ant	#12 – #16	Jul – Sep
	Foam Beetle	#10 – #14	Jul – Sep, under overhanging trees
Nymph	Bead-head Hare's Ear	#10 – #14	Mar – May, cold high water
	Bead-head Prince	#10 – #14	Deep plunge pools
	Stonefly nymph (dark)	#8 – #12	Apr – Jun snowmelt
	Caddis larva (green)	#12 – #14	All season
Wet	Sakasa kebari (reverse hackle)	#10 – #14	All season, tenkara or swung

Yamame 山女魚 · landlocked masu salmon

The "queen of the stream": silver flanks with dark oval parr marks. Yamame prefer the faster seams and riffles lower down than iwana, and are quicker and far more selective. Typically 15–25 cm.

Rod 7'6" – 8' · #2 – #3
Line Floating, double taper
Leader 9 – 12 ft · 6X – 7X
Tenkara 3.6 – 3.9 m rod

Type	Pattern	Hook size	When
Dry	Midge / Griffith's Gnat	#18 – #22	Mar – Apr, calm pools
	CDC Dun (olive)	#16 – #20	Mar – May, blue-winged olive hatches
	Parachute Adams	#14 – #18	All season
	March Brown / brown parachute	#12 – #14	Apr – May
	Elk Hair Caddis / CDC Caddis	#14 – #16	May – Sep, evenings
	Rusty Spinner	#14 – #18	Jun – Aug, evening rise
Nymph	Pheasant Tail	#14 – #18	All season
	Gold-ribbed Hare's Ear	#12 – #16	Mar – May
	Soft hackle (partridge & orange)	#12 – #16	Swung through riffles

Ugui & oikawa 鯎 · 追河 · Japanese dace & pale chub

The Chikuma's everyday fish, and great fun on light tackle. They shoal in the riffles and shallows, rise all day in summer, and can be fished year-round. Oikawa males colour up vivid blue and red in early summer.

Ugui, breeding colours

Oikawa, breeding male

Rod 6'6" – 7'6" · #1 – #3
Line Floating
Leader 9 ft · 7X

Type	Pattern	Hook size	When
Dry	Midge / small parachute	#18 – #22	All year, warm afternoons
Dry	CDC Caddis	#16 – #18	May – Sep
Wet	Soft hackle spider	#16 – #20	Swung across the current
Nymph	Pheasant Tail (unweighted)	#16 – #20	All year

Introduced species

Rainbow trout 虹鱒 · nijimasu

Stocked in the main river and some larger tributaries, and covered by the same 16 March – 30 September season. Rainbows hold in the deeper runs and pools of bigger water and grow well beyond the native fish.

Rod 8'6" – 9' · #4 – #6
Line Floating, weight forward; sink tip for streamers
Leader 9 ft · 3X – 5X

Type	Pattern	Hook size	When
Dry	Elk Hair Caddis	#12 – #14	May – Sep, evenings
Dry	Parachute Adams	#12 – #16	All season
Nymph	Bead-head Pheasant Tail	#12 – #16	All season
	Bead-head Prince	#10 – #14	Deep runs
	Stonefly nymph	#8 – #10	Apr – Jun high water
	Egg pattern	#10 – #14	Early season
Streamer	Woolly Bugger (olive, black)	#6 – #10	High or coloured water
Streamer	Zonker / Muddler Minnow	#4 – #8	Dawn and dusk

Smallmouth bass コクチバス

An invasive predator now established in the Chikuma and famous at Lake Nojiri. Hard-fighting and aggressive on a fly from late spring to autumn. Releasing bass back alive is restricted in parts of Japan, so check the local rule before you fish for them.

Rod 9' · #6 – #7
Line Floating, weight forward; intermediate for the lake
Leader 7.5 – 9 ft · 0X – 2X

Type	Pattern	Hook size	When
Streamer	Clouser Minnow	#2 – #6	May – Oct
	Woolly Bugger (olive, brown)	#4 – #8	May – Oct
	Crayfish pattern	#4 – #8	Rocky bottoms, summer
Surface	Popper / foam slider	#2 – #6	Jun – Sep, dawn and dusk

Carp 鯉 · koi

Big, wary fish cruising the slow margins and backwaters of the Chikuma. Sight-fishing to them in summer is the closest thing here to flats fishing, and they can be fished all year.

Rod 9' · #6 – #8
Line Floating, weight forward
Leader 9 ft · 1X – 3X

Type	Pattern	Hook size	When
Nymph	Carp Hybrid / soft-hackle nymph	#6 – #10	May – Oct, to feeding fish
Nymph	San Juan Worm	#8 – #12	After rain
Surface	Bread fly / foam berry	#6 – #10	Summer, calm water

Fly box

The patterns, up close.

The flies from the tables above, drawn so you can match them in a tackle shop. Hook sizes are the range to carry.

Dry flies

Elk Hair Caddis

#10 – #16The all-round searching fly, May to September
Parachute Adams

#12 – #18All season, for every trout and char here
Royal Wulff

#10 – #12Floats high in fast, broken pocket water
Stimulator

#10 – #12Pocket water and stonefly hatches
CDC Dun (olive)

#16 – #20Spring olive hatches for selective yamame
Parachute Ant

#12 – #16Summer terrestrial, July to September
Foam Beetle

#10 – #14Under overhanging trees in summer
Griffith's Gnat

#18 – #22Midges on calm pools, and for ugui

Nymphs & wet flies

Bead-head Hare's Ear

#10 – #16Cold, high water from March to May
Bead-head Prince

#10 – #14Deep plunge pools and runs
Pheasant Tail

#12 – #20All season, the one nymph to never be without
Stonefly nymph

#8 – #12April to June snowmelt
Caddis larva (green)

#12 – #14All season, bounced along the bottom
Sakasa kebari

#10 – #14Reverse-hackle tenkara fly, fished wet
Partridge & Orange

#12 – #16Soft hackle swung through riffles

Rods & lines

What to pack.

Water	Rod	Line weight	Leader & tippet	For
Small mountain streams	7' – 7'6"	#2 – #3	7.5 – 9 ft · 5X – 6X	Iwana, yamame
Medium rivers	7'6" – 8'6"	#3 – #4	9 – 12 ft · 5X – 7X	Yamame, iwana, ugui
Chikuma main river	8'6" – 9'	#4 – #6	9 ft · 3X – 5X	Rainbow trout, ugui
Bass and carp	9'	#6 – #8	7.5 – 9 ft · 0X – 3X	Smallmouth bass, carp
Tenkara	3.3 – 3.9 m	Level line #3 – #4	1 m of 5X – 6X tippet	Iwana, yamame

If you bring one rod, make it a 7'6" #3. It covers almost every stream within half an hour of the house.
Tenkara was born on streams like these. A fixed-line rod and a handful of kebari is the lightest, most local way to fish them.
Wading: felt or studded soles for slick boulders, and chest waders from March to June when the snowmelt is icy.
Storage at the house: the double garage has room to hang waders and rig rods ready for the morning.

Season calendar

How the year fishes.

16 March – April Opening
Cold water, small flies
Snow still on the banks. Fish are deep and slow: nymph the pools, and watch for midday midge and olive hatches on the calmer runs. Midges #18–22, olives #16–20.
May – June Snowmelt
High water, big hatches
Main rivers run high and coloured, so head for the smaller tributaries. Caddis, March Browns and stoneflies bring fish to the surface. Dries #12–16.
July – August Summer
Terrestrials and evening rises
Clear, low water. Fish the shade with ants and beetles through the day, then caddis and spinners at dusk. Go higher for cooler water. Terrestrials #10–16.
September Closes 30 Sep
Last casts
Cooler days, coloured-up fish feeding hard before spawning. Small dries and soft hackles, fished carefully. Dries #14–18.
October – mid March Trout closed
Dace, chub and carp
Iwana, yamame and rainbow trout are off limits while they spawn. Ugui, oikawa and carp in the Chikuma can still be fished on light tackle.

Permits & rules

Before you wet a line.

Every river in Japan is managed by a local fisheries cooperative, and you need its permit (yūgyoken) to fish. They are inexpensive and the money goes back into the river.

Buy a permit first. Day tickets are sold at the cooperative office, tackle shops and some convenience stores, and many cooperatives now sell them online. Buying from a warden on the bank costs more.
One permit, one cooperative. The Kōsui cooperative covers the Chikuma and its tributaries around Iiyama. The Zako River, Yomase River, Seki River and Lake Nojiri each have their own.
Respect the closed season and closed water. Trout and char fishing ends on 30 September. Some headwaters, and the water around the Nishi-Ōtaki dam on the Chikuma, are closed all year.
Return small fish. Iwana, yamame and rainbow trout of 15 cm or less must go back. We encourage barbless hooks and releasing all wild iwana and yamame.
Carry a bear bell. Asiatic black bears live in these valleys. Make noise on the walk in, and fish with a partner in the upper streams.
Watch the water. Streams below dams and after heavy rain can rise quickly.

Planning a fishing trip?

Tell us your dates and what you'd like to catch, and we'll point you to the right water, permits and local guides.

Check dates & enquire

Char, trout and clear mountain water.

Rivers and lakes near the house.

What lives here, and what it eats.

Native species

Introduced species

The patterns, up close.

Dry flies

Elk Hair Caddis

Parachute Adams

Royal Wulff

Stimulator

CDC Dun (olive)

Parachute Ant

Foam Beetle

Griffith's Gnat

Nymphs & wet flies

Bead-head Hare's Ear

Bead-head Prince

Pheasant Tail

Stonefly nymph

Caddis larva (green)

Sakasa kebari

Partridge & Orange

What to pack.

How the year fishes.

Cold water, small flies

High water, big hatches

Terrestrials and evening rises

Last casts

Dace, chub and carp

Before you wet a line.

Planning a fishing trip?