A high plateau, not a peak
Kirigamine is a wide grassland plateau in central Nagano, straddling the cities of Suwa, Chino and Shimo-Suwa. Its high point, Kurumayama at 1,925 m (6,316 ft), is the official summit, but Kirigamine really means the whole plateau — Kurumayama, Kowashimizu, Hashima wetland and the small hill of Monomi-iwa. It is part of Yatsugatake-Chūshin-Kōgen Quasi-National Park, and one of the lowest peaks on the Hyakumeizan list.
The terrain was shaped about a million years ago by lava flows and later covered, during the Ice Age, with grass rather than forest. Cold winters and strong winds make tree establishment difficult, which is why the plateau still looks today like an alpine meadow — and why both Japan's first glider training and one of its largest day-lily colonies developed here. Among the Hyakumeizan, Kirigamine reads more as a place to walk than a mountain to climb.
Nikko-kisuge: the yellow summer
Kirigamine's national-level fame rests on the Nikko-kisuge (yellow daylily) colonies that turn the slope from Kurumayama-no-Kata to the summit golden from late June through mid-July. The blooms are one-day flowers that wilt by afternoon, so photographers gather at Kurumayama-no-Kata at dawn.
Damage from a growing sika deer population has shrunk the lily field considerably in recent years. Local volunteers and the prefecture have built deer-exclusion fencing; the difference in vegetation inside and outside the fences is dramatic and a sobering reminder of how much of Japan's scenic landscape is now actively maintained. Renge-tsutsuji azaleas in June, matsumushi-sō in August and silver susuki grass in September give Kirigamine a four-season palette beyond the headline daylily week.
The shortest Hyakumeizan loop in Japan
The most popular way to tag Kirigamine is the Kurumayama-no-Kata loop: a 1.5-hour walk from the Kata trailhead (1,820 m) up the daylily slope to the summit and back. Elevation gain is barely 100 metres, the trail is wide gravel, and on a clear day the small Kurumayama shrine on top opens onto a 360-degree panorama of Yatsugatake, Mt. Fuji, the Southern Alps, the North Alps and Mt. Asama.
Hikers who want a proper day take the longer Chōchō-Miyama and Hashima wetland traverse from Kirigamine Nature Centre, around 4–5 hours over grassland, wetland and grassland again. Two ski areas (Kurumayama-Kōgen and Kirigamine) run summer lifts that cover sections of the same ridge, which lets less confident hikers shorten the day without losing the view.
Access from Tokyo: take the JR Chūō Line super-express to Chino or Kami-Suwa Station (around 2 hours), then a local bus or taxi (about 30–40 minutes) to Kurumayama-no-Kata or the Kirigamine interchange. By car, the Venus Line skyway delivers you directly to the trailhead car park — the line between hiker and sightseer here is unusually thin.
Hashima wetland: the other Kirigamine
Climbing only Kurumayama means seeing half the plateau. To the northwest, Hashima-ga-hara wetland (1,630 m) is the southernmost high-altitude bog in Honshū and a designated Natural Monument. A 3 km boardwalk loops the basin past yama-dori-zenmai fern, watasuge cottongrass and hakusan-fūrō geranium — a different ecosystem from the grass plateau above, built up over twelve thousand years of peat accumulation.
An old footpath from the wetland south to Kurumayama once served as a side route of the Nakasendō between Shimo-Suwa and Chino, and is still walkable today via the Okukiri hut. Starting at Hashima and finishing on Kurumayama is the local trick for avoiding the Kata-side crowds in daylily season.
Wind, fog, and afternoon thunder
Kirigamine's name literally means "plateau of fog" — for good reason. The summit sits more than 10 °C below Suwa city in the basin, and on summer afternoons visibility can fall to 20 metres within minutes. A windproof shell and a light fleece belong in the day pack even in July.
The genuine hazard on this mountain is summer afternoon lightning. Grassland and wetland mean almost no shelter, and storm cells form rapidly over the plateau in July and August. Check the JMA lightning nowcast, plan to be off the summit by 14:00, and respect the forecast. Mountain rescue statistics for Kirigamine are dominated by lightning strikes and hypothermia rather than falls, which is exactly because the terrain is so easy that visitors arrive underdressed.
The standard kit is long sleeves and trousers, a wind shell, a thin fleece and full rain gear — yes, even in August. A headlamp covers the case of a boardwalk navigation error in fog. In winter the Kurumayama and Kirigamine ski areas operate, but the hiking sections need snowshoes or skis. Winter Kirigamine is beautiful and a separate gear problem from summer Kirigamine.
The view, and the birthplace of Japanese gliding
The Kurumayama summit panorama is one of the broadest on the Hyakumeizan list: Yatsugatake to the east with Mt. Fuji beyond, the Southern Alps southward, the Central and Northern Alps to the west, Mt. Asama and Mt. Myōkō to the north. Almost no other single Japanese peak puts the country's major ranges in one frame. The Yatsugatake skyline reads cleanest on cold, dry mornings in autumn and winter.
It is also worth knowing that Kirigamine is the historical birthplace of Japanese gliding. In the early Shōwa era, the country's first serious glider training programme ran on this plateau, and the Kirigamine gliderport still operates today. Wind, terrain and altitude — the same three ingredients that give hikers their view also give pilots their thermals. From the summit you can sometimes watch the gliders circling below the ridge while you stand on it.
