Chichibu Geopark

Basic points

The brown part of Toraiwa is a mineral called stilpnomelane, and the white part that fills the cracks is a mineral called calcite. The rock took on this shape after being exposed to high pressure deep underground, and folding and piling on top of each other many times. The rock is said to have been named Toraiwa (literally means “tiger rock” in Japanese) because the pattern resembles the fur of a tiger.

There is also a monument engraved with a waka (poetry) that is said to have been made by Kenji Miyazawa, a famous Japanese poet and writer of children’s literature when he was out on a geological excursion in this area.