100 caves of Yoshimi, luminous moss and a world war II factory site: a country designated historical site home to a national natural treasure. And home to Koropokkuru. This post also contains information for the cherry blossoms in the area and the annual 100 Caves Sakura Matsuri (festival).
100 Caves of Yoshimi
One of our first adventures of 2015, brought us to the hundred caves of Yoshimi, a country designated historical site. We’ve been a few times since and I’ve updated this post several times over the years.

Back in 2015, it was our first time to visit the caves and an attraction of that type. I wasn’t sure how much the kids would enjoy it. Much to my delight, they were really eager to explore the terrain and the facilities on site.
Japan’s Cappadocia

The caves are tombs and there are actually 219 of them. They are the largest cluster of tombs of this type in the whole of Japan and have been nicknamed the Japanese Cappadocia. A description I must admit I find hyperbolic.
100 caves of Yoshimi: Home of the little people
Another fun fact about these caves is that they were once believed to be the houses of little people. The “Koropokkuru” of Ainu folklore, similar to Leprechauns or fairies in my own culture.
Underground military factory site

Although Japan’s Cappadocia it is not, the area is worth a visit for its unusual landscape and the history. The 100 caves of Yoshimi are tombs of a 1400 hundred year old burial mound. They are also home to an underground military factory site, built toward the end of World War II.
The underground military factory site is on the ground floor in tunnels carved into the mountain. The kids thrilled in running around, and pretending to be super heroes fighting evil. (Yes, I know, the irony!) These huge caves were dug at the end of World War II for an underground airplane engine factory that never really realised. It had begun manufacturing airplane engine parts before the factory was complete, around July 1945, but when the war ended so did manufacturing and the factory was never completed. The biggest shame in it is that more than 10 of the designated national historic site’s “hyakuana” were lost in the construction.

The caves (/tombs) themselves were only excavated about 60 years before World War II by Tsuboi Shogoro. Thankfully, they have been pretty well preserved since the end of World War II. My kids really enjoy climbing the dozens of steps made to give better viewing of, and in some cases access to, the caves. The stairs are quite steep and there is a lot of them so I would advise you leave your buggy / stroller in the car. Or park it by one of the buildings in the courtyard as you can wheel a buggy through the bunkers. The accessible caves have low entrances and while some of them are difficult for adults to enter they are no problem for kids. My kids quite like playing house in them!
Facilities

There are a couple of restaurants and shops within the site of 100 Caves of Yoshimi. There is also a museum (officially Reserve Cultural Property Center) and in the reception building they have an event space. The Reserve Cultural Property Center has some excavated items on display from the Jomon Period, but it is best known for its comma-shaped bead making class. My kids (at the time of publishing in 2015) like to play with the toys that they set out in this event space at the entrance. At New Years they have traditional New Year toys set out and during the year they have different types of toys for kids to play with.

They always have some toys and colouring pages and markers available for young children to play with. We have been to some of their festivals were they typically offer some sort of free craft. On special occasions they also put out some Jomon period clothes (cloth robe essentially) for people to try on and take a photo.
Hikarigoke ~ a national natural treasure

Another point of interest of the site is that is home to a national natural treasure; hikarigoke. Hikarigoke is luminous moss, and a type of moss that is very precious in the region of Kanto (area around Tokyo) as one of the plants that grows naturally. It shines best from April to October and the darker it is the easier it is to see, so actually a rainy day or late afternoon might be the best time to witness this natural phenomenon.
Another national natural treasure in Saitama.
Cherry Blossom Festival at the 100 Caves of Yoshimi
The cherry blossoms at the 100 caves of Yoshimi are of the Somei Yoshino variety (the main variety in Japan that are white, although they often look pink in photos!). There are only a couple of cherries on the grounds, but there is a large line of them on the embankment at the car park for the caves. The embankment is along the Ichino River. The cherry blossoms along the embankment will be lit up nightly during the period of the bloom.



Each year, there is festival on during the period of the bloom. It is normally held on the first Saturday of April. For the first time in four years, it will be on Saturday April 1st 2023. The festival usually entails Taiko drum performances, festival stalls and craft corner, with the light up at night. The 100 Caves normally cost 300 yen to enter, but for the day of the main cherry blossom festival it is usually free in. Unfortunately, Yoshimi town (like several other towns in Saitama) are using Walkerplus as their official portal in 2023 and it does not give details of the contents of the festival.
>>Don’t miss these sakura also in Yoshimi. <<
100 Caves of Yoshimi Information

One thing to note: it is not the safest of places to bring more than 2 small children per adult. The hill is very steep and there are limited guard rails and the ones that do exist my kids would slip through! Also, in the summer and autumn they have a problem with killer hornets. All that said, it is still a place worth visiting!
- You can partake of craft workshops on the grounds if you book in advance.
- The afore mentioned play area in the main reception building is available all year round and included in the cover price to the site.
- There are 2 restaurants, one of which is also a shop, and a rest area.
- In addition, there are plenty of vending machines.
- There are toilets and a changing mat.
- They have a number of festivals during the year.
- During festivals and on Saitama Day the entrance fee is waived.
Hours: 8.30 am to 5 pm, 7 days a week.
Cost: Free entry for children up to 6 years old. 200 yen for primary school aged children. 300 yen for children over 12 years old and adults. Free parking for up to 250 cars.
Address: 324 Kita Yoshimi, Yoshimi Town, Hiki District, Saitama
Tel: 0493-54-4541
100 Caves of Yoshimi Access
Bus : from Tobu Tojo Line Higashimatsuyama station bound for 百吉見穴.
Car: 5 km from Higashimatsuyama Interchange of the Kanestsu expressway, in the direction of Konosu.
For more information in English on the history of the caves, please take a look at Jojoebi designs detailed blog post about them.
That is quite a different site to see, amazing that there are so many of them and I’ve never heard of them before!
We have lots of secret or hidden treasures and pleasures in this area. 😉