Mt Omuro Lava Caves

Useful Information

Location: Narusawamura Ichien, Narusawa-mura, Minamitsuru-gun 401-0320 Yamanashi Prefecture
At the road , mini parking lot (2 cars max) is trailhead for 富士精進線 (Fuji-Seishin Trail).
(35.4525407, 138.6475598)
Open: no restrictions.
Fee: free.
Classification: SpeleologyKarst cave
Light: bring torch
Guided tours: self guided
Photography: allowed
Accessibility: no
Address: Mt Omuro Lava Caves, Narusawamura Ichien, Narusawa-mura, Minamitsuru-gun 401-0320 Yamanashi Prefecture.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
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Mt Omuro Lava Caves are numerous small lava caves of different size which are located at the northern foot of Mt Omuro (1,468 m asl). There is a walking trail which connects the caves and the summit with the road. The trailhead is a small parking lot for two cars and a small sign in Japanese. But the trail is maintained, so it seems it is used by walkers. The hiking area is called 大室山のブナ林 (Ōmuroyama no bunabayashi, Beech forest on Mt. Omuro).

All the caves are called Fuketsu or Wind Cave, which is the Japanese term for caves emanating cold air in summer. There are several ice caves in the area, as this region has snow and temperatures below 0 °C in winter. Caves which have additional openings higher up they get a slow convection flow in summer. Cold air flows out the lower entrance producing the cool spot effect, while warm air is sucked in higher up. Inside it coold down, becomes heavier and powers the convection.

富士風穴 (Fujifūketsu, Fuji Wind Cave) (35.4511620, 138.6523530)

本栖風穴 (Motosufūketsu, Motosu Wind Cave) (35.4467010, 138.6505171)

大室風穴 (Ōmuro Fuugetsu, Omuro Wind Cave) (35.4520448, 138.6585495)

神座風穴 (Jinzafūketsu, Kamukura Wind Cave) (35.4407214, 138.6604725)