Ichimai Iwa Monolith
Ichimai Iwa Monolith is a towering rock on the banks of the Koza River. It is more than 500 meters wide and 100 meters tall. The rock was created 14 million years ago when magma pooled in an enormous underground chamber. Pressure built, causing a crack in the ground from which the magma and other volcanic materials emerged, forming a large caldera. As the magma cooled and hardened, and the volcanic materials eroded, it left a 20-kilometer wide arc of rock, known as the Kozagawa Dike. Ichimai Iwa is the best-preserved part of that huge ring of stone. It is still being pushed upwards by the earth, so it continues to grow taller. Ichimai Iwa is remarkably smooth, whereas many of the other nearby rocks that were formed during the same cataclysmic event are severely eroded and have a honeycomb texture. According to local legend, the monolith is protected by a dog that once chased away an evil spirit that was eating the other rocks. Every April and August, a few minutes before sunset, it is possible to see a shadow resembling a dog cast on the side of the rock. Flowers bloom from cracks in the rock all year round, including rare Japanese toad lilies (hototogisu; Tricyrtis hirta) and ancient species of moss.