Narusawa Ice Cave
A vertical loop through a lava tube that holds ice pillars year round, around 0 to 3 C inside. Low ceilings mean helmets and a lot of crouching. Roughly 150 m long, 15 minutes to walk.
Places
Fuji's lava caves.
Under the forest on Fuji's north west flank runs a network of lava tubes left by the 864 eruption. Three are open to visitors, and all of them stay close to freezing whatever the season.
The caves
Which one to visit
Fugaku Wind Cave
A flatter, wider tube once used to store silkworm cocoons and seeds because of the constant cold. Easier than the ice cave, and often visited on the same ticket.
Saiko Bat Cave
The largest tube in the area at over 350 m, home to hibernating bats. Helmets provided, sections are very low, closed in winter to protect the colony.
How they formed
The Jogan eruption of 864 sent lava north into what is now Aokigahara. Surface lava cooled and hardened while molten rock drained out beneath, leaving hollow tubes.
Practical
Before you go
- · All three sit along the Aokigahara forest edge between Lake Saiko and Lake Motosu
- · Retro green line bus from Kawaguchiko Station reaches the ice cave and wind cave stops
- · Bring a jacket even in August, inside temperatures stay near freezing
- · Flat shoes with grip, floors are wet lava rock with metal stairs
- · Not suitable for large backpacks, pushchairs or anyone unhappy in tight spaces
Plan