Drive from Nirasaki into the mountains of Sudama-cho in Hokuto City, climbing steadily along the prefectural road towards the Masutomi Radium Onsen area, and after a few bends a stretch of emerald water and a white arch bridge suddenly appear before you.
This is Lake Mizugaki (Mizugaki-ko), the artificial lake held back by the Shiokawa Dam, and in autumn the slopes around the lake turn a mix of red, yellow and orange.
On a clear day, when the wind happens to drop, the whole sweep of autumn leaves and the white Rokumeikyo Ohashi Bridge are reflected together on the lake, one of the most characteristic autumn scenes in northern Yamanashi Prefecture.
The questions people ask most when planning are: when are the autumn leaves at Lake Mizugaki at their best? How long can you walk by the lake? Is it worth stopping off to see Mt Mizugaki on the way? And how do you get there without a car?
This article draws on information published by the Japan Weather Association’s tenki.jp, the Hokuto City Tourism Association, Hokuto City Hall and Yamanashi Prefecture’s Shiokawa Dam management office to set out the autumn-leaf season, the must-see spots, access and itineraries all in one place.
If you are planning an autumn itinerary around Yatsugatake, Kiyosato or Shosenkyo in Yamanashi, by the end you will be able to decide whether Lake Mizugaki fits in.
Where Is Lake Mizugaki? Getting to Know the Shiokawa Dam and the Masutomi Area
Lake Mizugaki is in Hishi, Sudama-cho, Hokuto City, Yamanashi Prefecture; it is a reservoir formed by the multi-purpose Shiokawa Dam, and the lake takes its name from Mt Mizugaki to the north.
According to the Hokuto City Tourism Association’s introduction to Lake Mizugaki, the Shiokawa Dam was completed in 1998, and the lake water comes from the headwaters of the Shiokawa River flowing down from Mt Mizugaki and Mt Kinpu.
The lake surface is about 900 metres above sea level, much higher than the Kofu Basin, so the autumn colours appear a little earlier than in the towns below.
Lake Mizugaki sits at the entrance to the Masutomi Radium Onsen area, and further into the mountains from the lake is the Masutomi area, home to hot-spring inns, the Hontani River valley and the Mt Mizugaki trailhead.
Hokuto City calls this the Masutomi area, and it is one of the areas in the city with the greatest concentration of famous autumn-leaf spots.
The White Arch of the Rokumeikyo Ohashi Bridge Is the Lake’s Signature
The white arch bridge across the lake is called the Rokumeikyo Ohashi Bridge, and the Hokuto City Tourism Association singles it out as a photo highlight.
In spring it is surrounded by green forest, in autumn it is set off by red and yellow leaves, and in winter the lake may even freeze over completely, so it looks quite different in every season.
Yamanashi Prefecture’s Shiokawa Dam facilities page also lists the Rokumeikyo Ohashi Bridge, the visitor centre, Yosha no Yu and the dam observation deck as the main facilities around the lake.
A Lake in the Kobushi UNESCO Eco Park
Hokuto City’s introduction mentions that Lake Mizugaki lies within the “Kobushi UNESCO Eco Park” recognised by UNESCO.
Upstream of the lake are the Kinpusan and Mizugakiyama headwaters, selected as one of the “Heisei 100 Best Waters”, and their clear water is one reason the valley scenery in this area is so beautiful.
When Are the Autumn Leaves at Lake Mizugaki at Their Best? Timing Your 2026 Visit
The autumn-leaf season at Lake Mizugaki falls roughly between mid-October and mid-November, with slightly different dates given by different sources.
The Japan Weather Association’s tenki.jp autumn-leaf page for the Lake Mizugaki area gives the usual peak as mid-October to early November, and the 2026 peak forecast is the same range.
The Hokuto City Tourism Association’s Lake Mizugaki page gives the peak as early to mid-November, a little later than tenki.jp.
When introducing the autumn leaves of the Masutomi area, Hokuto City Hall says the real autumn-leaf season here is mid-October to mid-November.
Putting these three sources together, we most recommend visiting Lake Mizugaki from late October to early November, a period covered by both tenki.jp and Hokuto City Hall, and early November also overlaps with the Tourism Association’s peak.
The Japan Weather Association’s Overall Forecast for 2026
The Japan Weather Association’s 2026 autumn-leaf forecast says that this year the peak across most of the country will be around the usual time or later than usual.
In eastern Japan, including Yamanashi, temperatures were low in the first half of September, but have been high from the second half of September and are expected to stay high through November, so the peak at most famous autumn-leaf spots is forecast to be around the usual time or slightly later.
The Japan Weather Association also says that tenki.jp will update the forecast three or four times up to November, so it is safer to check the latest status once more a week before you set off.
Different Altitudes, Different Timing
The surface of Lake Mizugaki is about 900 metres up, while Mizugakiyama Nature Park to the north is about 1,455 metres above sea level, so the autumn-leaf seasons at the two places are not quite the same.
The Hokuto City Tourism Association gives the peak at Mizugakiyama Nature Park as mid-October to early November, so if you want to see both the mountain and the lakeside in one go, aim to go around late October.
If the lakeside is still a little green when you go, heading some way up the mountain will usually bring deeper colours.
Main Tree Species and Colours
Both tenki.jp and the Hokuto City Tourism Association list maples (momiji), Japanese oak (mizunara) and lacquer trees (urushi) as the main species here.
The maples bring red, the Japanese oaks lean towards yellow-brown, and the lacquer trees are often among the first to turn red, so the slopes show layers of red, yellow and orange mixed together.
Must-See Autumn-Leaf Spots at Lake Mizugaki
Lake Mizugaki is not large, but its shoreline winds, so the view changes a great deal depending on where you stand, and it is worth picking at least two or three spots to take in slowly.
The Rokumeikyo Ohashi Bridge and Reflections on the Lake
The classic view is from the shore looking towards the white Rokumeikyo Ohashi Bridge, with mountains covered in autumn leaves behind it.
The Hokuto City Tourism Association particularly mentions that when the wind drops the lake reflects the colours of the surrounding mountains, so you have a better chance of photographing reflections in the morning or evening, when the wind tends to be lighter.
The Lakeside Loop Walk
The Hokuto City Tourism Association recommends a lakeside loop of about 4 kilometres that starts at the Mizugaki-ko Visitor Centre and passes the observation deck and Yosha no Yu.
The route follows the lakeshore, and in the autumn-leaf season you can see the lake and mountain colours from different angles all the way round, making it the easiest way to enjoy the autumn leaves at Lake Mizugaki.
The 4-kilometre route is not long, but there are ups and downs along the way, so wear comfortable walking shoes and allow time for taking photos too.
Around the Mizugaki-ko Visitor Centre
The Mizugaki-ko Visitor Centre is on the lakeshore and serves as the tourist information point for the Masutomi area, with souvenirs, a light-meals restaurant and toilets.
The autumn set in Yamanashi Prefecture’s Shiokawa Dam photo gallery features the enkianthus (dodan-tsutsuji) beside the visitor centre, a great spot for some warm-up photos.
The Dam Observation Deck and the Shiokawa Dam
If you want to see the dam itself, go to the dam observation deck, which looks down on the lake and the dam wall from another direction.
The Hokuto City Tourism Association’s information mentions that on weekdays staff from the Shiokawa Dam management office give explanations to visitors from 9:00 to 15:00; you need to contact the Shiokawa Dam management section in advance, and a visit takes about an hour.
If you collect Japanese dam cards, note that dam cards are also handed out from 9:00 to 15:00 at weekends and on national holidays.
Side Trips to Mt Mizugaki and the Masutomi Area
You can see Lake Mizugaki itself in an hour or two, so if you have time to spare, we highly recommend heading further north and adding Mt Mizugaki and the Masutomi area.
Mt Mizugaki: Granite Pinnacles and Autumn Leaves
The Hokuto City Tourism Association’s introduction to Mt Mizugaki says that Mt Mizugaki is 2,230 metres high, is one of the 100 Famous Mountains of Japan and the 100 Famous Mountains of Yamanashi, and that the summit area is covered with saw-toothed granite pinnacles.
In autumn the white rock pinnacles contrast strongly with the autumn leaves on the mountainside, making it one of the most highly praised seasons on this mountain.
Climbing to the summit is an intermediate-level route; the Tourism Association gives the round trip as about 5 hours 30 minutes, with chains and rocky sections along the way, so it is not suitable on a whim or in ordinary casual shoes.
Next to Mizugaki Sanso near the trailhead there is a free prefectural car park, which the Tourism Association says holds 100 cars.
Mizugakiyama Nature Park: See Mt Mizugaki Without Climbing
If you do not plan to climb, the Hokuto City Tourism Association’s Mizugakiyama Nature Park page points to a great alternative.
This was the main venue of the 52nd National Tree Planting Festival in 2001, and it has a grassy plaza, a management building, a canteen and a campsite, from which you can look straight up at the rock pinnacles of Mt Mizugaki and the autumn leaves at its foot.
The park’s car park holds 100 standard cars but has no spaces for large coaches; the canteen is open from 9:00 to 16:30, closed on Wednesdays, and closed for winter from early December to late April.
Know the Forest Road Restrictions First
To reach Mizugaki Sanso or Mizugakiyama Nature Park, you need to drive along Yamanashi prefectural forest roads (including the stretch known as the Crystal Line), while Lake Mizugaki itself can be reached by prefectural road.
The Hokuto City Tourism Association warns that this forest road may be closed in heavy rain or after an earthquake of seismic intensity 4 or above, and it is also closed in winter, usually from about late November to late April, with the actual dates depending on road conditions.
The safe speed on the forest road is set at 20 km/h, and the road is narrow, making passing and turning difficult; except on some forest roads, large vehicles with 11 or more seats cannot use it.
So if your group is large and you plan to travel in a large vehicle, check how far you can drive when planning your itinerary.
The Hontani River Valley and the Masutomi Radium Onsen Area
Heading upstream from Lake Mizugaki brings you to the Hontani River valley, which runs through the Masutomi Radium Onsen area.
Hokuto City Hall’s introduction to the Masutomi autumn leaves mentions that the “Kinpusan and Mizugakiyama Headwaters”, where the Hontani River flows, were selected by the Ministry of the Environment as one of the Heisei 100 Best Waters in June 2008.
Waterside areas have been laid out along the valley, so in autumn you can stop off on the way to look at the stream and the autumn leaves, then warm up with a soak in the hot-spring area.
Opening Hours and Fees at a Glance
There is no admission charge for the Lake Mizugaki lakeside itself; the main things to watch are the visitor centre’s closing day and the winter changes to each facility’s opening.
The following is the information that could be confirmed from official or first-hand sources as of October 2026; we still recommend checking the latest notices again before you set off.
| Item | Details | Source |
|---|---|---|
| Lakeside and autumn leaves | Open all year, free; usual autumn-leaf season mid-October to mid-November | tenki.jp, Hokuto City Hall |
| Mizugaki-ko Visitor Centre | Closed on Tuesdays; winter opening with extra closing days from December to March | Yamanashi Prefecture Shiokawa Dam facilities page |
| Shiokawa Dam visits | Weekdays 9:00 to 15:00, contact in advance, about 1 hour | Hokuto City Tourism Association |
| Dam cards | Also available at weekends and on national holidays, 9:00 to 15:00 | Hokuto City Tourism Association |
| Mizugakiyama Nature Park canteen | 9:00 to 16:30, closed Wednesdays, closed for winter from early December to late April | Hokuto City Tourism Association |
| Parking | Free car park by the lake | tenki.jp |
The visitor centre’s opening hours are given differently on Yamanashi Prefecture’s Shiokawa Dam page and on tenki.jp, so exact times are not given here; go by the facility’s notice on the day.
tenki.jp also notes that at weekends and on national holidays enquiries are handled by the Mizugaki-ko Visitor Centre.
Getting to Lake Mizugaki
Lake Mizugaki is in the mountains and public transport is infrequent, so driving or a private charter is the most convenient option, but you can also get there by bus from JR Nirasaki Station.
By Car: From Sudama IC on the Chuo Expressway
According to the Hokuto City Tourism Association’s visitor centre page, it takes about 30 minutes to drive from Sudama IC on the Chuo Expressway to Lake Mizugaki.
After leaving the interchange, turn right towards Kiyosato, then turn right at the second set of traffic lights, “Nishikawabashi-Nishizume”, onto Prefectural Road 28 towards Masutomi (the Masutomi Radium Line), and you will reach the lakeside in another 20 to 30 minutes.
If you want to continue to Mizugakiyama Nature Park, the Tourism Association gives about 60 minutes from Sudama IC, and about 50 minutes towards Mt Mizugaki.
The mountain road has many bends and traffic increases at weekends in the autumn-leaf season, so allow plenty of time for the return journey and avoid driving on the forest road after dark.
By Train and Bus: Changing at JR Nirasaki Station
The nearest railway station to Lake Mizugaki is Nirasaki Station on the JR Chuo Main Line, which you can reach on the Chuo Main Line from the Shinjuku direction; check the JR timetable to see whether limited express trains stop there.
The Hokuto City Tourism Association lists two bus routes; one is the Yamako Town Coach route bus bound for “Masutomi Onsen”, getting off at “Shiokawa”, a ride of about 50 minutes.
The other is the Mizugaki route of the “Kayagatake-Mizugaki Den’en Bus”, getting off at “Mizugaki-ko Visitor Centre”, a ride of about 46 minutes.
The one-way adult fares listed on the Tourism Association’s page are 1,280 yen and 1,500 yen respectively; this is the information visible as of October 2026, so go by the bus companies’ notices for actual fares and timetables.
Neither route has many services a day, so be sure to check the time of the last bus back in particular, so that you do not miss it and end up stranded in the mountains without transport.
Private Charter or Taxi
If you want to link Lake Mizugaki, Mizugakiyama Nature Park and Masutomi Onsen in one day, or are travelling with older relatives or children, a private charter is much less effort than changing buses.
But remember that the forest road restrictions mentioned above are based on seating capacity: vehicles with 11 or more seats cannot enter these forest roads, so if you are a larger group travelling in a HiAce (5 or more), check the vehicle type and route with the car company first.
How Long to Stay and Suggested Itineraries
If you only see the lakeside, 1 to 2 hours is enough; add the area around Mt Mizugaki or the hot springs and it makes a good half-day to full-day itinerary.
| Type of trip | Suggested time | What to do |
|---|---|---|
| Easy lake visit | About 1 to 2 hours | Around the visitor centre, photos of the Rokumeikyo Ohashi Bridge, part of the lakeside walk |
| Lakeside loop | About half a day | The lakeside loop of about 4 km plus the dam observation deck |
| Lakeside plus Mt Mizugaki views | About a full day | Lake Mizugaki, Mizugakiyama Nature Park, the Hontani River valley, Masutomi Onsen |
| Hiking trip | A full day or more | About 5 hours 30 minutes for the round trip to the summit of Mt Mizugaki; staying nearby the night before is recommended |
Sample Day Trip from Tokyo
Leave Tokyo in the morning and take the Chuo Expressway to Sudama IC, then start the morning at Lake Mizugaki to see the Rokumeikyo Ohashi Bridge and the reflections on the lake.
Have lunch at the visitor centre or in the Masutomi area, then head up the mountain in the afternoon to Mizugakiyama Nature Park to see Mt Mizugaki and the autumn leaves at its foot.
On the way back, time permitting, you can stop off at the Kiyoharu Art Colony or Shosenkyo, or stay a night in the Masutomi Radium Onsen area and move on to the Yatsugatake area the next day.
Tips on Photography and What to Wear
Wind is the enemy of reflections on the lake, so if the water is rippling when you arrive, take a lakeside walk or have a coffee first, and come back to the arch bridge once the wind drops.
Days are short in the mountains in autumn, and with mountains all around, the sun may disappear behind the ridges earlier in the afternoon than on the plains, so if you want to photograph sunlit autumn leaves on the slopes, it is best to arrive around midday.
The lake surface is about 900 metres up and much cooler than central Kofu, and from late October mornings and evenings can be close to winter temperatures, so a light down jacket or windproof jacket is very useful.
If you are also going up to Mizugakiyama Nature Park or the Mt Mizugaki trailhead, these are more than 500 metres higher still, so bring an extra layer of warm clothing.
Combining Other Autumn-Leaf Spots in Yamanashi
The autumn-leaf season at Lake Mizugaki partly overlaps with other famous spots in Yamanashi Prefecture, so if you want to make your trip richer, see our Shosenkyo Autumn Leaves Guide or Kiyoharu Art Colony Autumn Leaves Guide.
If you want to see valley autumn leaves deeper in the mountains, our Nishizawa Valley Autumn Leaves Guide is also a popular choice in the same season.
Lake Mizugaki Autumn Leaves FAQ
When is the best time to see the autumn leaves at Lake Mizugaki?
The sources put the autumn-leaf season at roughly mid-October to mid-November, and we most recommend going from late October to early November.
For 2026 the Japan Weather Association forecasts that eastern Japan will mostly be around the usual time or slightly later, so the safest thing is to check the latest peak status on tenki.jp once more a week before you set off.
Do I need a ticket for Lake Mizugaki?
You do not need a ticket for walking by the lake and enjoying the autumn leaves; tenki.jp lists it as open all year and free to visit.
Can I get to Lake Mizugaki without a car?
You can take the route bus or the Kayagatake-Mizugaki Den’en Bus from JR Nirasaki Station, a ride of about 46 to 50 minutes.
However, services are infrequent, so if you also want to visit the Mt Mizugaki area, driving or a private charter gives you more flexibility.
Is it worth going just for the lake, without climbing?
Yes: the lakeside loop of about 4 kilometres shows you the lake, the arch bridge and the autumn leaves on the slopes, and Mizugakiyama Nature Park also lets you see Mt Mizugaki without climbing.
Is Lake Mizugaki suitable for older relatives or children?
Yes: you can see the lake and the arch bridge right around the visitor centre without walking the whole lakeside loop, so people with limited stamina can choose a short stretch and take it slowly.
What should I watch out for when visiting Lake Mizugaki?
There is a big temperature difference between morning and evening in the mountains, so bring a warm jacket in autumn, and the forest road may be closed in heavy rain, after earthquakes or in winter.
The visitor centre is closed on Tuesdays, so if you want to eat or buy souvenirs there, remember to avoid that day.
Final Thoughts: Lake Mizugaki in Autumn Is Best Taken Slowly
Lake Mizugaki is not the kind of famous spot that is packed with people the moment you get out of the car, but a place where you can quietly watch the lake, the bridge and the changing colours of the mountains.
Aim for late October to early November, add Mizugakiyama Nature Park or Masutomi Onsen on the way, and you can see the most characteristic autumn scenery in Hokuto City in one trip.
Further Reading
- Shosenkyo Autumn Leaves Guide, Yamanashi: Best Time, Sengataki Falls, Ropeway Fares and Access
- Kiyoharu Art Colony Autumn Leaves Guide, Yamanashi: Peak Time, Museum of Light, Tickets and Access
- Nishizawa Valley Autumn Leaves Guide, Yamanashi: Best Time, Nanakama Godan Falls and Bus Access
- Shirakoma Pond Autumn Leaves Guide, Nagano: Peak Time, Moss Forest Trail, Car Park and Bus Access
Buses around Lake Mizugaki are infrequent and the mountain roads have many bends, so when you are travelling with older relatives or children, have lots of luggage, or want to link Lake Mizugaki, Mt Mizugaki and Masutomi Onsen in one day, getting around is often the most demanding part.
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