Chokai-san (2,236 m) is a massive stratovolcano straddling the Akita–Yamagata border, rising almost straight from the Japan Sea coast as a dominant white cone. Locals call it "Dewa Fuji." It is the second-highest peak in Tohoku, and its true summit, Shinzan, is a jumbled lava dome formed by the eruption of 1801. The combination of a sea-level base, a volcanic summit, and wide coastal and inland views makes it one of the region's standout climbs.
Why Fukada Chose Chokai-san
Kyuya Fukada included Chokai-san in Nihon Hyakumeizan. The book is ordered roughly north to south, not by rank — it sits between Hayachine and Gassan in that geographic sequence. Fukada admired the mountain's isolation: standing apart from the main inland ranges of Tohoku and rising straight from the coast, Chokai commands a sweep of sea and plain that more clustered peaks cannot match.
The Mountain
| Item | Detail |
|---|---|
| Elevation | 2,236 m (7,336 ft) — second-highest in Tohoku |
| True summit | Shinzan (新山), a 1801 lava dome |
| Rim peak | Shichiko-san (七高山), 2,229 m |
| Prefectures | Akita / Yamagata |
| Volcano status | Active; last eruption a small steam eruption in 1974. Alert Level 1 (quiescent), 2026 |
| Hyakumeizan position | Included (book order is roughly north-to-south, not a ranking) |
| Typical season | June – October |
The mountain has two summits that hikers often confuse. The true high point is Shinzan (新山, 2,236 m), the lava dome thrown up by the 1801 eruption; reaching it means a short scramble over jumbled lava blocks just past the Omuro hut. Shichiko-san (七高山, 2,229 m) sits on the outer crater rim and is the first high peak many people reach. Plan the extra scramble to Shinzan if you want the genuine summit.
Lower on the western flank, well below and apart from the summit, lies Chokai-ko (鳥海湖), a crater lake of the older western Chokai volcano. It sits in the flower-field zone around Ohamayama on the lower Kisakata and Fukura routes, not within the summit crater.
The Routes
Kisakata Route — Hokotate (Akita side)
Grade: Moderate–Challenging
- Trailhead: Kisakata / Hokotate 5th station (象潟口・鉾立), 1,160 m
- Character: The most popular approach, with a well-maintained trail passing the flower fields near Ohamayama and Chokai-ko before the upper crater.
Yunodai Route (Yamagata / Shonai side)
Grade: Moderate–Challenging
- Trailhead: Yunodai 5th station (湯ノ台口), 1,200 m
- Character: Approaches from the Shonai side past Taki-no-koya hut. A quieter line onto the summit massif.
Fukura Route — Ohira (Yamagata / Shonai side)
Grade: Moderate–Challenging
- Trailhead: Fukura / Ohira (吹浦口・大平), 1,080 m
- Character: A second Shonai-side option, also passing the lower flower-field zone.
The summit massif can be reached from either side, and stronger parties sometimes combine routes as a traverse.
Getting There
The trailheads are reached via the Chokai Blue Line, a toll-free mountain road, with seasonal buses serving the main 5th stations in summer.
By rail: Take the Joetsu Shinkansen to Niigata, then the JR Uetsu Main Line (limited express Inaho) to Sakata or Tsuruoka. An alternative is the Yamagata Shinkansen to Shinjo, then the Rikuu-saisen line to Sakata. Note that neither Sakata nor Tsuruoka is on the Shinkansen network itself — the final leg is a conventional line.
By air: Shonai Airport (ANA from Tokyo Haneda, about one hour) is a fast alternative, with onward car or bus to the trailheads.
Mountain Huts
- Omuro-goya (山頂御室小屋, ~2,100 m) — the summit hut, just below Shinzan. Run by Chokaisan Omonoimi Shrine.
- Ohama-goya (御浜小屋, ~1,700 m) — on the Kisakata/Fukura approach near the flower fields. Run by Chokaisan Omonoimi Shrine.
- Taki-no-koya (滝の小屋, ~1,280 m) — on the Yunodai route. Run by Yuza town.
Flora and Wildlife
Chokai-san sits on Honshu, so the resident bear is the Asiatic black bear (ツキノワグマ), found in the lower forest zones. A bear bell is sensible on forested sections. (Bear spray is associated with Hokkaido's brown bears and is not the standard precaution here.)
The open volcanic gravel of the upper mountain supports notable endemic alpine plants, including Chokai-fusuma (チョウカイフスマ, Chokai cushion-pink) and Chokai-azami (チョウカイアザミ, Chokai thistle). The richest flower fields lie around Ohamayama and Chokai-ko in midsummer.
On a clear day the summit view takes in the Japan Sea, Tobishima island, the Shonai plain below, and the inland ranges of Tohoku.
Seasonal Guide
June – July: Snowfields can linger into early summer; an ice axe or crampons may help before mid-July.
August: Peak season, with the best chance of clear summit views and the alpine flowers at their height.
September – October: Generally the most stable weather, with autumn colour developing on the lower slopes.
Practical Tips for Foreign Visitors
Volcanic status: Chokai is an active, monitored volcano, currently at Alert Level 1 (quiescent) as of 2026. Check the JMA Sendai monitoring page (volcano 209) before your trip in case conditions change.
The summit scramble: Reaching the true summit at Shinzan requires hands-on scrambling over loose lava blocks past Omuro hut. If you stop at Shichiko-san on the rim, you have not reached the high point.
Base region: The Shonai area around Sakata and Tsuruoka is one of Japan's finest food regions, known for rice, soba, and Japan Sea seafood. It is worth a night at the foot of the mountain.
Frequently Asked Questions
Which peak is the true summit of Chokai-san?
The true high point is Shinzan (新山, 2,236 m), the lava dome from the 1801 eruption, reached by a short scramble over loose lava blocks just past the Omuro hut. Shichiko-san (七高山, 2,229 m) sits on the outer crater rim and is the first high peak many hikers reach, but it is not the summit.
When is the best time to climb Chokai-san?
The typical season is June to October. August is peak season with the best chance of clear summit views and alpine flowers at their height, while September to October generally offers the most stable weather. Snowfields can linger into early summer, so an ice axe or crampons may help before mid-July.
How do I get to Chokai-san without a car?
By rail, take the Joetsu Shinkansen to Niigata, then the JR Uetsu Main Line limited express Inaho to Sakata or Tsuruoka; alternatively the Yamagata Shinkansen to Shinjo, then the Rikuu-saisen line to Sakata. By air, Shonai Airport (ANA from Tokyo Haneda, about one hour) is a fast option. Seasonal buses serve the main 5th stations in summer.
Do I need to worry about bears on Chokai-san?
Chokai-san is on Honshu, so the resident bear is the Asiatic black bear, found in the lower forest zones. A bear bell is sensible on forested sections. Bear spray is associated with Hokkaido's brown bears and is not the standard precaution here.
Is Chokai-san safe to climb as an active volcano?
Chokai is an active, monitored volcano currently at Alert Level 1 (quiescent) as of 2026, and its last eruption was a small steam eruption in 1974. Check the JMA Sendai monitoring page (volcano 209) before your trip in case conditions change.
This guide is part of the Japan's 100 Famous Mountains: Complete Hyakumeizan Guide series.
