Narusawa Hyoketsu Ice Cave and Fugaku Fuketsu Wind Cave Travel Guide
These two lava caves were formed from molten rock that flowed out during volcanic activity around Mount Fuji.
Narusawa Hyoketsu Ice Cave (Narusawa Hyōketsu) is said to have been created by lava from the Jōgan eruption in 864 AD. It is more than a cool sightseeing spot; it reveals both the terrain shaped by volcanic activity and the history of how people used the cave's low temperatures.
Lava Caves in the Aokigahara Forest
When lava flows, the surface can cool and harden first while the molten rock inside drains away, leaving behind a hollow cavity.
At Narusawa Hyoketsu Ice Cave and Fugaku Fuketsu Wind Cave (Fugaku Fūketsu), the rough black basalt walls and lava-flow formations reveal the geological history of Mount Fuji's foothills.
Cave Temperatures Average Around 3°C
The average temperature inside both caves is about 3°C, with temperatures remaining between 0°C and 4°C throughout the year.
A jacket is often needed even in summer. At Narusawa Ice Cave, the temperature difference from the outside air can exceed 20°C, so pause near the entrance and let your body adjust before going inside.
A Site Protected as a Natural Monument
Narusawa Ice Cave was designated a Natural Monument of Japan in 1929 (Shōwa 4), and Fugaku Wind Cave has the same designation.
The rocks and ice inside the caves are part of the natural environment rather than exhibits, so staying within the handrails and walkways and not touching the rock walls or ice lets you enjoy the terrain's features without damaging nature.
Differences Between Narusawa Ice Cave and Fugaku Wind Cave
Visiting both caves and comparing their terrain can give you a deeper understanding of how they differ.
Narusawa Ice Cave is introduced as a vertical, ring-shaped cave with large changes in elevation, while Fugaku Wind Cave is a relatively gentle horizontal cave.
Narusawa Ice Cave: A Vertical Ring-Shaped Cave with Elevation Changes
At Narusawa Ice Cave, you descend a staircase and make a loop through low passages and spaces with ice, going down to about 21 meters underground in a cave full of ups and downs.
Its total length is about 153 meters, and at the lowest point the ceiling is only about 91 centimeters high, so in the narrow sections you need to crouch low, keep your distance from the person ahead, and move in a single file.
Fugaku Wind Cave: A Horizontally Spreading Cave
At Fugaku Wind Cave, you walk through a gentle horizontal cave about 201 meters long with a maximum height of 8.7 meters, where you can observe lava shelves and ropy lava (pahoehoe).
There are sections with low ceilings and some stairs, so it is important not to walk as if it were a flat indoor facility.
Different Impressions of the Ice and Terrain
Narusawa Ice Cave is known for the ice pillars formed when water dripping from the ceiling freezes, while at Fugaku Wind Cave you can focus on the shapes of the lava and traces of its use as a natural refrigerator in addition to ice pillars.
The condition of the ice changes with the season and the state of the cave, and the ice pillars at Narusawa Ice Cave grow largest around April, so observe the natural conditions of the day rather than expecting the same scene as in photos.
Decide Your Point of Comparison for an Easier Visit
Here is a summary of viewpoints for comparing the two caves.
| Point of View | Narusawa Ice Cave | Fugaku Wind Cave |
|---|---|---|
| Cave shape | Vertical with elevation | Gentle horizontal |
| How to walk | Crouch low | Watch your footing |
| Ice to notice | Ice pillars and walls | Pillars and cold-storage traces |
| Reading the terrain | Vertical changes | Flow of lava |
Top Things to See at Narusawa Ice Cave
At Narusawa Ice Cave you can experience the shape of a lava cave through not only the cold air but also its narrowness and changes in elevation.
The visit takes roughly 6 to 15 minutes, so rather than rushing through, take time to observe the changing rock walls and ceiling as long as you don't block others.
Low-Ceilinged Lava Tunnel
Part of the passage has a ceiling as low as about 91 centimeters, so you move through it by bending at the waist or turning sideways.
Looking only overhead can make you neglect your footing, so it is safer to check ahead, then the ceiling, then your feet in turn as you go.
Ice Pillars That Grow from Frozen Water Drops
The ice pillars form when water seeping from the ceiling drips down and freezes, and in some years they can grow to about 50 centimeters in diameter and 3 meters in height.
Their shape and size are never fixed, and the changing forms created by shifts in temperature and moisture are a highlight.
Traces of Use for Cold Storage
Inside the cave there is an ice storage chamber, a place that conveys the history of preserving ice by making use of the low temperatures.
Learning that a natural cave was put to use in daily life and industry draws your attention to local culture as well as the scenery.
Top Things to See at Fugaku Wind Cave
At Fugaku Wind Cave you can observe the patterns left by the flow of lava and the openness of the space as you make your way through the horizontal cave.
The visit takes about 15 minutes, and comparing it with the ups and downs of Narusawa Ice Cave lets you truly feel how the same volcanic activity produced different cave landscapes.
Lava Shelves and Ropy Lava
On the walls and floor there are spots that preserve the shapes formed as the lava flowed, and the basalt walls are also known for their sound-absorbing quality.
Looking for rope-like surfaces and rock shaped into steps makes it easier to imagine the movement of the lava before it hardened.
History as a Natural Refrigerator
Fugaku Wind Cave has a history of use as a natural refrigerator, where its low temperatures were used to store silkworm eggs until the early Shōwa period.
The way people used the cave's natural conditions before mechanical refrigeration became common is another fascinating aspect of the site.
Entrance Fees and How Long to Allow
Narusawa Ice Cave and Fugaku Wind Cave are separate facilities, each with its own entrance fee.
Knowing how long each visit takes makes it easier to plan if you want to see both.
Entrance Fees: 350 yen for Adults, 200 yen for Children
The entrance fee for each cave is 350 yen for adults and 200 yen for elementary school-age children and younger, with discounts for groups of 15 or more.
If you visit both, you pay separately for each, so checking in advance will help you avoid confusion on the day.
Allow About 6 to 15 Minutes per Cave
As a guide, allow about 6 to 15 minutes for a visit inside Narusawa Ice Cave and about 15 minutes for Fugaku Wind Cave.
Building in the walk from the parking lot to the entrance and any waiting time during busy periods will give you a comfortable margin for your visit.
What to Wear and Bring for Visiting the Caves
Inside the caves you need to prepare for the cold, wet floors, and low ceilings.
Even on hot days outside, it is safer not to enter wearing only light clothing meant for city walking.
Bring a Jacket in Every Season
A long-sleeved jacket protects you from temperatures of around 3°C and can also shield your arms in narrow sections close to the rock walls.
Choose something easy to put on and take off, and keep it in an accessible part of your bag so you can wear it at the entrance.
Choose Non-Slip Sneakers
Wear clothing that allows easy movement and non-slip sneakers, and avoid sandals, high heels, and miniskirts.
Shoes with thin soles or ones that slip off easily are not suited to wet stairs and uneven passages.
Protect Yourself with a Hat and Gloves
A hat helps protect your head from the low ceilings, and gloves are useful when gripping the cold handrails.
If you need extra head protection, ask the staff about borrowing a helmet before entering the cave.
Use a Raincoat on Rainy Days
Since having one hand occupied is dangerous when going up and down the cave stairs, a raincoat is recommended rather than an umbrella.
A folding umbrella can block your view, so bring a lightweight raincoat that is easy to put on.
Prepare According to the Situation
Here is a summary of clothing and items organized by situations likely to occur inside the caves.
| Situation | What to Prepare | What to Avoid |
|---|---|---|
| Cold | Long-sleeved jacket | Staying lightly dressed |
| Wet floors | Sneakers | Sandals |
| Low ceilings | Hat | Large bags |
| Rain | Raincoat | Umbrella inside the cave |
How to Plan a Visit to Both Caves
Narusawa Ice Cave and Fugaku Wind Cave have separate entrances, and thinking about travel and cave entry separately makes planning easier.
Even if you visit both, leave room to switch to just one depending on your condition or the weather.
- Physical condition: whether crouching low and stairs will be manageable
- Weather: whether it affects cave conditions or transportation
- Travel: whether you have confirmed your return transportation
Compare the Walking Conditions Before You Go
If low crouching or major elevation changes are a concern, check the terrain at Narusawa Ice Cave in advance; the route descends about 21 meters underground.
Fugaku Wind Cave, introduced as a relatively gentle horizontal cave, also has stairs and low ceilings, so neither is like an ordinary walking path.
Check the Day's Opening Hours and Transport Information
The opening hours are 9:00 to 17:00 from April 1 to October 15, 9:00 to 16:30 from October 16 to November 15 and from March 16 to March 31, and 9:00 to 16:00 from November 16 to March 15, and they may change depending on the weather and cave conditions.
If you use public transportation, check the official bus timetable, and if you come by car, check each facility's entrance and parking information before you set out.
Safety Tips for Your Visit
The passages inside the caves are narrow and generally one-way, so it is hard to turn back partway through.
Before entering, check your physical condition and any concerns about walking, and prioritize not overexerting yourself.
Use the Handrails on the Stairs
Narusawa Ice Cave has about 192 steps and Fugaku Wind Cave about 130 steps, so on wet stairs take small strides, don't rush, and use the handrails.
Follow local rules for using your smartphone or camera, and avoid looking at your screen while walking on the stairs.
Keep Distance in the Narrow Passages
Leave a little space as you move so you don't bump into the person ahead if they stop.
Not trying to overtake and not rushing those behind you helps keep everyone safe and comfortable.
Check Whether You Can Enter in Advance
Because the route is one-way and includes many stairs, it is not accessible to wheelchair users or visitors who have difficulty walking.
Since operations may change depending on the weather and cave conditions, check the official website's information on the day of your visit.
Here is a summary of safe behavior organized by situation.
| Situation | Action | What to Keep in Mind |
|---|---|---|
| Before entering | Check your condition | Don't overexert |
| Stairs | Use the handrails | Take small strides |
| Narrow passages | Move in single file | Keep your distance |
| After exiting | Adjust your clothing | Mind the temperature gap |
Summary: Enjoy Comparing the Two Lava Caves
Narusawa Ice Cave offers the experience of moving through ups and downs and narrow passages, while Fugaku Wind Cave leaves a lasting impression with the lava terrain in its horizontal cave and its history as a natural refrigerator.
Both have cold and slippery spots, so prepare a jacket, sneakers, and a hat, and follow the handrails and one-way guidance during your visit.
Calmly observing the day's expressions of ice and rock reveals the connection between the nature at the foot of Mount Fuji and the lives of the people here.
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