A Lava Tube Carved by Mount Fuji
About ten thousand years ago, lava poured from a crater near the summit of Mount Fuji and ran east across the volcano's lower slopes. Geologists call this the Mishima lava flow. Where the surface of the moving lava cooled and hardened while the molten rock beneath kept flowing and eventually drained away, it left a hollow corridor of stone. Komakado Wind Cave is one such corridor, and it lies beneath an ordinary district of houses and farm plots in Gotemba City, Shizuoka Prefecture.
The cave divides into two passages, known locally as the main cave (honana) and the branch cave (edana). Figures differ between sources: the main passage is recorded at lengths ranging from roughly 240 to 290 meters, with the branch adding around another 100 meters. The lit, walkable section is shorter, about 150 meters into the main passage and a further 45 meters or so into the branch. Inside, the air holds at roughly 13 degrees Celsius the year round, cool in summer and mild in winter.
Residents of Gotemba rarely use the formal name. To them it is simply the kazaana, the wind hole.
Why It Became a National Natural Monument
On 8 March 1922, the Japanese government designated Komakado Wind Cave a National Natural Monument. The reasoning recorded by the Agency for Cultural Affairs rests on a small number of points. Lava caves are uncommon in Japan to begin with. Among the wind caves scattered around the base of Mount Fuji, Komakado is one of the larger examples. And its interior preserves the moment of its own creation with unusual clarity, so that a visitor can read in the walls and ceiling how the lava moved, slowed, and set.
The 1922 citation singles out one feature in particular: the lava stalactites that hang from the ceiling, formed when the still-hot rock of the roof dripped and froze.
When Mount Fuji was inscribed on the UNESCO World Heritage List in 2013, under the title "Fujisan, sacred place and source of artistic inspiration," thirty-three associated sites were listed alongside it. Komakado Wind Cave was considered as a candidate component, since it too was formed by the mountain's volcanic activity. In the end it was left off the list, because its link to the religious worship and artistic tradition of Mount Fuji could not be demonstrated. Its value, then, is read as geological rather than devotional, a record of how the mountain works rather than how it has been revered.
Inside the Cave
The entrance opens into a tall chamber where the ceiling rises as much as twenty meters overhead. After the bright walk from the road, the scale of the opening tends to stop people for a moment before they start down the stone steps.
Several formations are worth slowing down for. Along stretches of the wall, hardened lava hangs in vertical folds that look like a row of ribs, a feature local guides call rokkotsu-jo yogan, or rib-shaped lava. It formed as the still-soft skin of the flow slumped and was dragged downward. From the ceiling hang the lava stalactites named in the designation, short and blunt rather than the thin spires of a limestone cave. Underfoot, the cooled surface wrinkled into rope-like and wave-like ridges, the so-called ropy lava that records the last sluggish movement of the flow before it stopped. One broad open stretch is known as the Senjojiki, a name borrowed from the image of a hall spread with a thousand floor mats.
Near the point where the two passages divide is a spot called the kamidana, the household altar. In the early Showa era, a bronze mirror about eleven centimeters across was found wedged in a gap in the lava here, a small reminder that people have been entering this cave for a very long time.
Komakado is also a habitat for creatures found nowhere else. Three species carry the cave's name in their own: the Komakado ground beetle, the Komakado millipede, and the Komakado pseudoscorpion. All are true cave dwellers, adapted to permanent darkness, with eyes reduced or lost altogether. Four kinds of bat roost in the cave, and a golden alga known as Hikarimo grows where a little light reaches.
The steady cool air once had a practical use. Gotemba and the wider region around Mount Fuji supported a busy silk industry from the nineteenth century into the twentieth, and the cave was used to store silkworm egg paper, the sheets on which moths had laid their eggs. The low temperature held the eggs back until farmers were ready for them to hatch.
Getting There and What Lies Around
By train, the cave is about a twenty-minute walk from Fujioka Station on the JR Gotemba Line. By car, it is roughly ten kilometers from the Gotemba interchange of the Tomei Expressway and about 5.5 kilometers from the Susono interchange. A free unpaved parking area sits across Prefectural Route 155 from the entrance, a short walk away. Large buses are directed to use the Usagijima junction.
Beside the entrance, groundwater filtered through Mount Fuji rises to the surface and may be drunk straight from the source, a welcome stop on a hot day. The cave itself is looked after by a local volunteer preservation association rather than a commercial operator, and the lane of houses and fields above gives almost no sign of what runs beneath it.
Komakado is listed among Gotemba's twelve selected scenic spots. The city occupies the eastern flank of Mount Fuji and works well as a base for the mountain and its surroundings, with the slopes of the volcano visible on a clear day from much of the area.
- 📍 Plan Your Visit to Shizuoka
- Find tours, activities & transport passes near Komakado Wind Cave
- [ Mt. Fuji Views & Atami Hot Spring Resorts ]
Q&A
- Is the cave suitable for children?
- Yes. It is a popular family outing, and the walkable section is short enough for young children. Many enjoy the feeling of exploring an underground passage. The floor is uneven and the ceiling dips low in places, so an adult should stay close and watch for low rock.
- How long does a visit take?
- Most visitors spend about twenty minutes inside. The route runs along the lit passages and back the same way.
- Will I be cold inside?
- The interior stays near 13 degrees Celsius throughout the year. In summer this feels refreshing, but some visitors find it chilly after a few minutes, so a light extra layer is worth carrying. Closed, sturdy shoes are recommended, since the floor is rough and water drips from the ceiling.
- Are helmets provided?
- No helmets are handed out at the entrance. The ceiling clears most people along the main passage, but it drops low in the branch passage and at a few other points. A hat offers some protection, and signs indicate where to keep your head down.
- Can I take photographs?
- Photography is generally allowed. The passages are lit, though not brightly, so a steady hand or a camera that performs well in low light will give better results.
Basic Information
| Name | Komakado Wind Cave (Komakado Kazaana / Komakado Fuketsu) |
|---|---|
| Location | 69 Komakado, Gotemba City, Shizuoka Prefecture |
| Designation | National Natural Monument |
| Designation date | 8 March 1922 |
| Designation criteria | (6) Caves; (10) Features formed by fumaroles and volcanic activity |
| Origin | Lava tube formed in the Mishima lava flow, roughly 10,000 years ago |
| Scale | Main passage approx. 240-290 m, branch passage approx. 100 m; lit section approx. 150 m (main) and 45 m (branch) |
| Interior temperature | About 13 degrees Celsius year-round |
| Hours | 9:00-17:00 (March-November); 9:00-16:00 (December-February) |
| Closed | Mondays in December-February (open on public holidays); 31 December. No closing day March-November |
| Admission | Adults 300 yen; high and junior high school students 200 yen; elementary students 100 yen; preschool children free |
| Access | About 20 min on foot from Fujioka Station (JR Gotemba Line); about 10 km from Gotemba IC or 5.5 km from Susono IC (Tomei Expressway) |
| Managed by | Komakado Wind Cave Preservation Association (local volunteers) |
References
- Database of National Cultural Properties, Agency for Cultural Affairs: Komakado Fuketsu
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/1321
- Gotemba Digital Museum: Komakado Wind Cave (National Natural Monument)
- https://www.city.gotemba.lg.jp/museum/muse-cat-004/128.html
- Gotemba City Tourism Association: Komakado Kazaana
- https://gotemba.jp/information/1137/
- Wikipedia (Japanese): Komakado Kazaana
- https://ja.wikipedia.org/wiki/駒門風穴
Last verified: 2026.05.26