All over the world, various natural formations have been discovered that look as if they were created by someone with meticulous calculations. But did you know that you can see such natural formations here in Hokkaido? This is the strange rock called "Kurumaishi" located at Cape Hanasaki in Nemuro City. As its name suggests, it is a large rock that looks just like a car tire. How on earth was it formed? To see the Kurumaishi, walk along the promenade from the parking lot at Hanasaki Cape. The surrounding area has been developed as a park, so you can walk along at a leisurely pace while enjoying the nature. Up ahead you will see the Hanasaki Lighthouse. It has been selected as one of the "50 Best Lighthouses of Japan" and stands at a height of about 10m. As you pass the lighthouse and approach the coast, you will see Kurumaishi. Cape Hanasaki, where Kurumaishi is located, is a sea cliff jutting out into the Pacific Ocean. The Kurumaishi, which resembles a giant wheel and is about 6 meters in diameter, looms out from there. The radial joints, a pattern of numerous columnar cracks spreading out radially, look like something that was artificially designed. It's hard to believe that this was formed naturally. However, if you look around at the rocks on the coast, you'll notice that they are all angular. If you have a good sense of intuition, you'll probably guess that this could be the original form of Kurumaishi.

(Photo courtesy of Nemuro City Tourism Association)

The angular rocks on the coast are dolerite, formed when magma underground cooled and solidified. The dolerite in this area is said to have been created during the Cretaceous period about 60 million years ago, when the hot, viscous lava cooled rapidly, after which seawater seeped into the still-molten rock, further cooling it and creating these Kurumaishi. Kurumaishi of this size are rare around the world, and were designated a national natural monument in 1939.

(Photo courtesy of Nemuro City Tourism Association)

The largest stone, measuring 6m in diameter, catches your eye, but if you look closely you'll see that there are several others measuring 1-2m in size. It may be a little strange to think that we can see something that was created 60 million years ago. As mentioned earlier, it has been developed as a park, so it is also fun to visit in the snowy season to see the Hanasaki Lighthouse and other sights. Please be careful when walking on the coast as it can be slippery. <Interview cooperation> Nemuro City Tourism Association Location: Tourist Information Center, 2-10 Kowacho, Nemuro, Hokkaido Phone: 0153-24-3104 Official website: https://www.nemuro-kankou.com