Recommended scenic driving route in Tohoku! Beautiful valleys, hot springs, and a magnificent geyser that lets you feel the breath of the earth! National Route 398 (Koyasu Road) [Akita Prefecture/Miyagi Prefecture]

National Route 398 is a long national highway with a total length of approximately 282 km that crosses central Tohoku, connecting Ishinomaki City in Miyagi Prefecture to Yurihonjo City in Akita Prefecture, passing through Onagawa Town and Minamisanriku Town

Next, I'd like to introduce the Oyasu Kaido, a road that runs from Yuzawa City in Akita Prefecture to Tsukidate in Kurihara City, Miyagi Prefecture

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The Koyasu Road, used to transport sea squirts from the Sendai Domain to the Akita Domain

The Oyasu Road was also known as the "Sea Squirt Road" during the Edo period because it was a route used to transport sea squirts from the Pacific Ocean to the inland areas of Akita Prefecture. It is a scenic drive course blessed with natural beauty, such as the Oyasu Gorge, and is particularly beautiful in late autumn when the leaves change color

This time, we'll take a drive along the Koyasu Road from Yuzawa City to Kurihara City, the opposite direction from where we usually go when we go to see sea squirts, and introduce the scenery and local cuisine along the way

Please note that the prices (including tax) mentioned in this article are as of August 18, 2026

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From Omote-machi 4-chome intersection in Yuzawa City to Nomura intersection in Yuzawa City

Starting from the Omote-machi 4-chome intersection where it crosses National Route 13 (old route), the road is a pleasant one that runs through hilly areas with many fields until Kawatsura-cho, famous for its lacquerware. After passing through the approximately 510m Yamaya Tunnel, it merges with the Koyasu Kaido (Akita Prefectural Road 108) at the Nomura intersection

A little detour, part 1: "Umai Sake Ryozeki" Ryozeki Brewery (Maemori, Yuzawa City)

Near the Nomura intersection is Ryozeki Brewery, known for brands such as "Ryōzeki," "Hanamura," and "Suigyoku."

Located in Yuzawa City, which produces about 80% of the sake-brewing rice in Akita Prefecture, this brewery boasts a history of over 150 years and brews fine sake using its own uniquely developed low-temperature, long-term brewing method

The main building and four inner storehouses, which have stood since the company's founding, were the first in Akita Prefecture to be designated as registered tangible cultural properties of Japan, and they are still in active use today, including as a shop

I bought some "sake that can only be bought at the brewery" inside a storehouse that is a cultural property!

Inside the cool, airy building, there was not only a shop but also a display of valuable materials that told the history of the sake brewery. After viewing them, I purchased a hidden sake that can only be bought here, "Sake that can only be bought at the brewery" (720ml: 1,936 yen)

This is a Junmai Ginjo sake brewed using "Akita Sake Komachi," a sake-brewing rice variety from Akita Prefecture, polished to 50%, the same ratio as Daiginjo sake. It has a slightly higher alcohol content of 16%

This was a delicious sake that was slightly sweet with a hint of effervescence, offering a fresh, fruity aroma and a rich, mellow flavor thanks to being unfiltered

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Yuzawa City Nomura Intersection ~ Yuzawa City Inaniwa Town

If you head south along the Koyasu Road, following the Minasegawa River, you will arrive in Inaniwa Town, the birthplace of "Inaniwa Udon," in about 10 minutes

Along the main road in this town, the birthplace of Inaniwa udon, there are several restaurants serving authentic Inaniwa udon, attracting many tourists every day

Furthermore, on the mountainside south of the town lies the site of Inaniwa Castle, where a replica castle tower now stands, also serving as a museum. From the observation room on the top floor, you can enjoy a panoramic view of the town and the Kurikoma mountain range

There is a slope car that goes from the parking lot up to the replica castle tower, and you can ride it for 430 yen (including admission to the replica castle tower), but unfortunately, it was closed on the day I visited, so I was unable to go up

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A little detour, part 2: Sato Yosuke Main Store, a restaurant specializing in Inaniwa udon noodles

I had a strong craving for authentic Inaniwa udon, so I stopped by the main store of "Sato Yosuke," which has been preserving its traditional manufacturing method for 166 years

Sato Yosuke's main store, which has branches not only in Akita Prefecture but also in the Kanto region and overseas, has a factory attached where you can observe how Inaniwa udon noodles are made

Two-flavor steamed rice bowl (1,000 yen) and chicken tempura (950 yen)

The "Two-Flavor Seiro" comes with two types of dipping sauces: soy sauce-based dipping sauce and sesame miso dipping sauce with walnuts. You can enjoy the smooth texture and firm bite of Inaniwa udon noodles with these two sauces

Furthermore, their tempura is also highly regarded, especially the chicken tempura made with Hinai chicken, a specialty of Akita Prefecture. The more you chew, the more the delicious flavor of Hinai chicken fills your mouth. Since quantities are limited, we recommend visiting early

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Inaniwa-cho, Yuzawa City ~ Koyasu Gorge Lake (Minase Dam)

You can drive on top of the Minase Dam, a rock-fill dam (large vehicles are not allowed), and enjoy the view of Lake Koyasu Gorge from the top of the dam

Around the time of the Obon festival, Lake Koyasu Gorge not only had a reduced water level, but the water was also muddy due to the previous day's rain, which made the scenery somewhat disappointing

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Lake Oyasu Gorge ~ Oyasu Gorge

From this point onward, mountains close in on both sides of the road, and the road's gradient becomes steeper

Upon arriving at "Aguri-kan Minase," a hot spring facility with a direct-from-the-farm produce market and a footbath, you'll find the entrance to a walking trail leading to "Oyasukyo Great Geyser" across the road

The walking trail also has an entrance and exit at the Kaneko Shoten parking lot, located upstream from Agri-kan Minase, and both of these parking lots are free of charge

A little detour, part 3: The breath of the Earth - Koyasu Gorge Geyser

From the entrance in front of "Agri-kan," descend about 60 meters down 406 steps to reach a walking path, and after walking upstream for about 5 minutes, you will find the large geyser

You can observe the continuous eruption of extremely hot water and steam at 98°C from exposed geological layers, accompanied by a roaring sound

There's a vent near the walking path, so you can feel the heat on your skin, making it the most recommended spot on this driving route

You can visit the site in about an hour from the parking lot, but if possible, we recommend taking your time to truly feel the pulse of the earth

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Koyasu Gorge to Hanayama Pass

Located beyond the large geyser, Koyasu Gorge Onsen boasts eight hot spring inns along the gorge and is a historic hot spring resort that was first opened during the Edo period

After passing Koyasukyo Onsen and then Okukoyasukyo Oyu Onsen, which is further into the mountains, the road becomes a series of hairpin bends, and you cross the Hanayama Pass, which marks the prefectural border, and enter Miyagi Prefecture

A little detour, part 4: The delicious, cold spring water of Kurikoma

This spring, located right by the road, provides mineral-rich, cold water from two pipes, making it drinkable. I filled up a water bottle with it and quenched my thirst during my drive

Please note that the parking area is across the road. Although traffic is light, cars pass by at high speeds, so please be very careful when crossing the road

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Hanayama Pass to Tsukidate

Hanayama Pass is relatively flat for a pass on the prefectural border, and doesn't really feel like a "pass crossing." Rather, Yuhama Pass further ahead offers better views of Mount Kurikoma and has a more authentic pass-like atmosphere

From Hanayama Pass to Hanayama Lake, there are many waterfalls such as "Shiraito Falls" and "Sakuza Falls," and it is recommended to take a stroll using the walking trails with parking lots

As you travel along the Koyasu Road, which follows a series of hairpin bends, alongside the Ichihasama River, the elevation gradually decreases and flat land opens up before you

In Hanayama, Kurihara City, the road crosses the Zasubashi Bridge over Lake Hanayama, and from here you can enjoy a drive with views of Lake Hanayama on your left

Enjoy the scenery and fishing at Hanayama Lake

Lake Hanayama is a reservoir with a circumference of 11 km and a depth of 40 m, created by damming the Ichihasama River with the Hanayama Dam. It is known for the beautiful cherry blossom trees along the lakeshore in spring and the autumn foliage, and in addition to smelt fishing being popular in winter, you can enjoy fishing all year round, including crucian carp fishing

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A little detour, part 5: Roadside Station Rotasato Hanayama, Yam Museum

Located just before crossing the Zashu Bridge, and given that Hanayama is a famous production area for "wild yam," it was given the nickname "Jinenjo no Yakata" (Wild Yam House)

The direct-from-the-farm corner sells wild yams, mountain vegetables, and mushrooms, as well as yams and vegetables grown by nearby farmers. The restaurant offers the "Yam Set Meal," which includes grated yam soup and grilled char, as well as the weekday-only "All-You-Can-Eat Soba Noodles," which is very popular

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A little detour: The Koun Mansion, a house associated with the swordsman Chiba Shusaku

The Koun Yashiki, the former residence of Sato Jutaro, who is said to have recognized the talent of Chiba Shusaku, a master swordsman of the Edo period and founder of the Hokushin Itto-ryu school of swordsmanship, in his youth, has been relocated and is now on display

The house, a traditional Japanese house over 230 years old, is designated as a tangible cultural property of the former Hanayama Village. You can view the inside of the house for a fee (210 yen for adults, 110 yen for high school students and younger). Unfortunately, it was closed on this day

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summary

The area around the Koyasu Road on National Route 398 will soon be experiencing autumn foliage, allowing visitors to enjoy bathing in the hot springs scattered along the road while admiring the changing leaves

Please note that the section from Hanayama Onsen in Kurihara City, Miyagi Prefecture to Minase Oyu in Yuzawa City, Akita Prefecture will be closed for the winter from late November to late April of the following year, so please check road information

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