Karato-ishi rock was part of the sector collapse of Mt. Chōkai approximately 2500 years ago, when a large amount of rocks collapsed and flowed down from the top of the mountain. Among the many rocks along Kitsakata Coast, this one especially stands out for its size, 4.3 m tall and 5 m wide.

Although it is on the coast now, this rock was once in the sea. In July 1804, an earthquake of estimated magnitude 7 occured off the coast of Kisakata. This caused the land around Kisakata to rise about 2 m, bringing this rock with it to where it now sits, above the surface of the sea.

On the top of the rock, you can see marks left by wave erosion from when it was in the sea.