Vegetarian's Japan Guide

Gunma Prefecture’s Hidden Gem: Chatsubomi Moss Park

Although moss is commonly seen across gardens in Japan, if you have a particular love towards the gorgeous green plant, visit Chatsubomi Moss Park (チャツボミゴケ公園)! The moss growing in the park isn’t one of the generic types as it can only be nurtured by the strong acidic mineral springs. It is a great off-the-beaten-path spot 20-minute drive away from Shiriyaki Onsen (尻焼温泉) and a 30-minute drive from Kusatsu Onsen!

Ⓒ ググっとぐんま観光宣伝推進協議会

As the park’s name has suggested, Chatsubomi Moss covers the park’s ground where the acidic sulfur-based hot springs flow.

Chatsubomi Moss is the most acid-resistant moss amongst the approximately 1,800 species in the world. If you want to meet this rare moss, Chatsubomi Moss Park is the best place in Japan because the moss-covered area is the biggest! Besides Gunma Prefecture, the only other spot where you can find it is in the Aso region in Kumamoto Prefecture.

Chatsubomi Moss Park’s History and Ana Jigoku (穴地獄)

Trekking up from the car park, you should notice that a part of the hill is dark red. In the Heian and Kamakura periods, these red rocks/soil were used as ingredients to produce dye.

More recently, the park used to be a mining spot that boasted Japan’s second-largest limonite production volume. Besides limonite, another product of the mining activity is pitted ground. Because if an animal fell into the large hole, it would not be able to get out and would die; the area was named Ana Jigoku, or hole hell in English.

The spot’s role as a mine ended in 1966 and was gifted to Nakanojō Town in 2012. In 2015, the park was listed in the Ramsar Convention protected site. And in 2017, it became a designated national natural monument.

While the pits were not good news to the wild animals, it is where Chatsubomi Moss grows in colonies. A 20-minute-long circular promenade is maintained around Ana Jigoku for you to observe the Chatsubomi Moss from all different angles.

Note that Ana Jigoku is 1.3km away from the parking lot. So to get to this mysterious scene, some effort is required.

Tip: Take the 100 yen shuttle at the reception/car park as there is still around a 300-meter-long slope walk to the moss. It arrives every 5 minutes. Sneakers are recommended.

The Relationship Between Chatsubomi Moss and Iron Ore

What most people are unaware of is the interesting relationship between Chatsubomi Moss and Iron Ore.

Apparently the iron ore was originally moss. Through the biomineralization process, Chatsubomi Moss, which has been absorbing the iron in the strong acidic spring water, is reborn as iron ore after a long period of time.

So the moss that you will see when you visit Chatsubomi Moss Park will also become iron in the (far) future!

Yoshigadaira Wetlands (芳ヶ平湿地群)

Because Chatsubomi Moss Park is located in Yoshigadaira Wetlands, created by Mt. Shirane’s volcanic activities, many other types of plants will grow in the park than moss. As you hike from the bus stop closer to Ana Jigoku, there are also a few small waterfalls. If you are very lucky, you might even be able to spot a Japanese serow!

Thanks to the volcanic activity of Mt. Shirane, the area around Ana Jigoku is covered by a light green carpet! In fact, Chatsubomi Moss isn’t the only type of moss growing in the park. As you walk on the wooden trek, you will notice other types of moss, making it heaven for those who adore the cuteness of the little green plants.

Important: Please stay on the promenade to protect the plants.

The Best Time to Visit Chatsubomi Moss Park

Ⓒ ググっとぐんま観光宣伝推進協議会
  • From mid-May to June: For the collaboration of light green moss and rhododendron.
  • Autumn: For the bright fall color surrounding the moss

Note that in summer, affected by the heat, the moss will most likely be brown in color.

Tip: Toilet facilities and a souvenir shop are next to the reception. It is where you can also find Chatsubomi Moss-flavored gelato!

Chatsubomi Moss Park’s Opening Hours, Admission Fees, and Access Information

  • Chatsubomi Moss Park is open from:
    • 8:45 am to 3:30 pm from late April to September
    • 8:45 am to 3 pm in October and November
  • The last bus
    • from the reception is at 3 pm (2:30 pm in autumn)
    • from Ana Jigoku is at 4 pm (3:30 pm in autumn)
  • The admission fee is 600 yen for elementary school students and above.
  • Chatsubomi Moss Park is around a 40-minute drive from JR Naganohara-Kusatsuguchi Station (長野原草津口駅).
  • From Kusatsu Onsen, Chatsubomi Moss Park is around a 30-minute drive.

Discover Other Attractions Nearby in Nakanojō 

Click the photo for more attractions in Nakanojō!

If you want to enjoy Guma Prefecture’s rural area, Nakanojō can be a nice option. It has one of the prefecture’s most famous hot spring towns, a gorgeous moss park, a few flower gardens, and more!

All of these attractions aren’t too far away from Chatsubomi Moss Park. So refer to our article on Kuni Village, the old name for a large part of Nakanojō!