On this seashore, there lies a 2-meter diameter rock called Oppai Iwa. Local legend says it was blown here by the eruption of Mt. Unzen. However, the truth is that it was originally part of the underground stratum here, and being harder, stronger, and bigger than other rocks around, it remained on the seashore. Though it is not known how this rock was formed, it has been hypothesized that it was made by bacteria living at the bottom of the sea in an area where methane-bearing water flowed. It is rumored that touching this rock can give you more breast milk or bigger breasts. There is another smaller “Oppai Iwa” here, which is 80 centimeters in diameter.