Caves of Saitama

Earlier this month I set off for another exploration of the nature in the Chichibu mountain area of western Saitama Prefecture. The original plan had been to visit a canyon I had encountered during the spring. But too many short nights left my body in need of sleep and I had to thank the cat for waking me up at 5 am since I apparently shut off my 4:30 alarm and dozed right off again. So, a late start, and then my plans were thwarted once more as I crossed into Chichibu and found fog in the valley. This led me to make the fruitless decision to head up a road for a view, but I missed the turn and got on a road that led to no view of the valley. After losing another 30 minutes, I decided I was out of time for driving way in to find that canyon. So, as I drove up R140 and thought of where to go, I spied the Kaminiwa Cave across the river and up the slope.

The Kaminiwa Cave is actually two caves close together, one of them referred to as a “half cave” (半洞窟). They have formed in a limestone cliff and are said to have been eroded by the Ara River (Arakawa 荒川) some 50,000 years ago. The cave was used during the Jomon Period by hunters as a shelter while they were away on hunting trips.

Access to the cave is from either downstream by the large torii gate where the path leads up to the trailhead to the route up to Mitsumine Shrine, or further upstream at a campground with a free day-use area. I came in from this way and followed a path a short distance to the cave. At first it appeared to be just a wide hollow under an overhanging cliff face. But I soon discovered there was a low passageway leading to an opening that led to a small but open chamber. To one side, a narrow corridor ran a short distance to a very narrow gap in the rocks with a view to a corridor beyond that soon turned right and disappeared into the darkness. I had only the light of my smartphone to illuminate the inside, though reflected sunlight came in enough to provide a very dim light. A couple of cave crickets sat on the wall at one end where a small gap revealed darkness beyond.

The second cave has a very high opening that has been partly closed with concrete with a door opening cut in. Once inside, it would seem like there’s only this open chamber with a vaulted ceiling. But on the left there are what look like steps cut into the limestone layers. Two large screws with loops for running ropes through were jutting out from the rocks. above the steps, there was a deep shadow. I crouched down and saw that the steps led up a narrow chimney. Holding my light up, I poked my head up into the opening and found a small chamber opened up above. There was a dark opening at the end that suggested that there was another chamber. I was about to clamber up when I noticed two bats were hanging from the ceiling. I wondered how they would respond to my intrusion. I didn’t want to disturb them. But if they began fluttering about, would they panic with a large moving object blocking their entrance? Would they pee on me? Where there more bats in the next chamber? I decided to duck back down again and make a note to return in the future with a proper light, perhaps at night when the bats would likely be out.

There are several caves around Saitama. Perhaps the most famous one is the Hashidate Limestone Cave near Urayamaguchi Station and the Urayama Dam. For a small fee, you can enter this cave, going in via a low tunnel that leads to a large open chamber with interesting cave formations. These formations do not rival Japan’s more famous famous caves but they are still interesting. There are some other shallow caves I have found while out driving, some of them marked on the map or with a trail marker, a couple not marked. Saitama’s longest cave is 2.1 km and it’s found somewhere in the Yakemame Ravine, just before R140 disappears into the long tunnel that leads to Yamanashi. This cave is not open to the general public, but I did try to find my way – unsuccessfully – into the ravine last summer. Inspired by my recent cave visit, I will be looking for more.

The mountains of Saitama are largely composed of ancient ocean sediments. Limestone, chert, sandstone, mudstone, and the metamorposed crystalline schist of the Sanbagawa Metamorphic Belt were all laid down way back in the eons past when this area was a seabed. Not only caves, but limestone mountains are also found in the area. The most famous is Bukosan, which is mined for its limestone to make concrete. Futagoyama is a mountain on a limestone ridge that has two steep-sided peaks. The Nakatsukawa Ravine also has many limestone cliffs and at least two caves that I know of.

Photos I took of the caves and mountains can be found on Flickr.

Here are two photos from the Hashidate Cave from an older post from many years ago.

Cave growth – Hashidate Cave
Into the limestone cave – Hashidate Cave

One response to “Caves of Saitama

  1. Many thanks for taking us into this cave; never had time to inspect it while I was in this area. Yes, there’s more sedimentary rock around the Kanto that one might inspect. It even gets a passing reference in Kojima Usui’s essay on the Japanese landscape: “The European Alps have limestone mountains, while ours do not. Limestone is leached away by the carbonic acid dissolved in water trickling down into the ground, or carried in subterranean streams, to form huge caves with narrow entrances, as can be seen in our own mountains of Chichibu and elsewhere … “

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