Mushikui Iwa Rock
Mushikui Iwa is a 60-meter-high rock in Takaike. Mushikui Iwa, meaning “insect-eaten rock,” is covered in honeycomb holes (tafoni). Local legend says that an evil spirit ate chunks out of the rocks. An alternative story told by practitioners of Shugendo (ascetic mountain worship) suggests that giant bees caused the holes. Modern geologists assign the patterning to erosion facilitated by salt crystals that formed between the layers of rock and expanded.
This rock is a remnant of the explosion that must have taken place in a large underground magma chamber 14 million years ago, leaving a circular volcanic depression more than 40 kilometers across. This magma cooled and hardened, forming a wide chain of rocks 22 kilometers long and 800 meters wide, now called the Kozagawa Dike.
A shrine sits at the base of the rock. According to local folklore, praying and placing a pebble with a hole through it inside the shrine can cure hearing problems. A short drive away, Botan Iwa (Peony Rock), also part of the Kozagawa Dike, shares the same rare pock-marked appearance. The name comes from a rock formation near the top that resembles a peony.