Sights to See
Seasonal views
Cautionary points

Chatsubomigoke Moss Park in Gunma prefecture’s Agatsuma district is an enchanting site with acidic waters and beautiful moss. The chatsubomigoke moss, a national natural monument, can be found here.

The park locates near the famous Kusatsu Onsen hot springs. The waters in the park are also from a hot spring, but they are highly acidic and not for bathing.

Chatsubomigoke moss can only be found in a few places throughout Japan. Visit Chatsubomigoke Moss Park for dream-like views of the moss and springs.

What is chatsubomigoke?

Chatsubomigoke is a type of moss that only grows in areas with highly acidic waters. Out of the approximately 1,800 or so moss species in the world, the chatsubomigoke is the most resilient to acidic waters.

In Japan, the chatsubomigoke can be found in Gunma’s Nakanojo area and in Kumamoto’s Aso area.

About Chatsubomigoke Moss Park

Chatsubomigoke Moss Park is one of the very few places throughout Japan where you can see the chatsubomigoke moss. The area was once actually a limonite deposit ground, and was the second producer of limonite in the country.

In 1966, the mines were closed down, and the area was managed as a recreational facility. The area was handed over to the town of Nakanojo in 2012, and in 2015, it was added to the Ramsar Convention list, an international treaty for the conservation of wetlands.

Chatsubomigoke Moss Park was designated as a national natural monument in 2017. The area is still protected and managed to maintain the natural beauty.

Chatsubomigoke and mines

Chatsubomigoke and the limestone mines have a surprising connection.

The iron ores mined in the area actually derive from the chatsubomigoke. Through the process of biomineralization, the moss hardens and mineralizes and after many years, it turns into iron ore.

The moss you see at the park will one day, too, become iron ore.

Where to see the chatsubomigoke

Pit of Hell where you can find the chatsubomigoke moss

“Anajigoku”, or the “Pit of Hell”, where you can see the chatsubomigoke

The chatsubomigoke moss can be found at the “Anajigoku” area of the park. It translates to “Pit of Hell”, and is given the name due to its extremely acidic waters that could kill any living creature instantly.

The hole was created by an eruption from Mount Kusatsu-Shirane. It produces sulfuric acids that the chatsubomigoke need to survive.

Pit of Hell at Chatsubomigoke Moss Park

Pit of Hell

The waters are steaming as they flow. Around the waters, you can find an endless carpet of the chatsubomigoke moss.

Chatsubomigoke Moss Park aerial view

Chatsubomigoke Moss Park from above

There is a path constructed around the Pit of Hell. You can circle the area in about 20 minutes.

Seasonal views

At the Pit of Hell, you can enjoy unique, seasonal views.


Chatsubomigoke moss with azaleas

Azaleas surrounding the moss

Between mid May and June, the bright red azaleas begin to blossom. The green chatsubomigoke moss look amazing right by the azaleas.


Chatsubomigoke and fall foliage

The fall foliage at the park

You can enjoy the fall foliage at the park. The surrounding trees change colors, and contrast the moss beautifully. The moss itself, too, is the most vibrant during the autumn months.


The park is closed throughout most of the winter months. However, there are snowshoe tours held irregularly, and during those days you can enter the park.

Since the Pit of Hell is warm, the area of the moss has no snow on them. The surrounding area is covered in snow, and you can see a rare sight of the chatsubomigoke moss surrounded with snow.

The snowshoe tour is usually held between the beginning of January and end of March.

Cautionary points

Here are some things to be aware of before visiting the park.

Wear comfortable shoes

Although there is a path created for walking, most of the paths are paved with dirt. Make sure to wear comfortable shoes, and avoid wearing sandals or heels.

Closed in the winter

Between December and the beginning of April, the park is closed. With the exception of the snowshoe tour days, the park is completely closed off.

Stay on the path

Aside from the moss, there are many living creatures in the park grounds. To conserve nature and protect wildlife, don’t stray from the path provided.


There are no public transportation stops near the park, so you would have to get there by car or taxi.

From Shinjuku Station

【Shinjuku Sta.】Joshu Meguri Highway Bus / for Kusatsu Onsen
→【Kusatsu Onsen Bus Terminal】30 minutes by taxi
→【Chatsubomigoke Moss Park】

From Maebashi Station

【Maebashi Sta.】JR Ryomo Line / for Takasaki
→【Shin-Maebashi Sta.】JR Agatsuma Line / for Manza
→【Naganohara-Kusatsuguchi Sta.】JR Bus / for Kusatsu Onsen
→【Kusatsu Onsen Bus Terminal】30 minutes by taxi
→【Chatsubomigoke Moss Park】

Hike the area!

The area surrounding Chatsubomigoke Moss Park is perfect for a hike. From the area of the park to Yoshigadaira, locating on the northern side of Mount Kusatsu-Shirane, you can go on a 12-kilometer hike.

On the hike route are observatory spots where you can view the wetlands and Kusatsu Onsen. This hike is a great way to enjoy Gunma’s nature!


938 Oaza Nakanojo, Nakanojo Agatsuma-gun, Gunma 
Apr. to Sep.: 9:00a.m. - 3:00p.m.
Oct. and Nov.: 9:00a.m. - 2:30pm.
Closed between November and April (exact dates vary annually)
Adults: ¥500
Elementary school students and below: free
Credit Card

Nearby Destinations