The rocks were discovered by the French corvette Bayonnaise in 1850, while surveying the islands south of Tokyo Bay.

[2] The above sea-level portion has a surface area of approximately 0.01 square kilometers, with a summit height of 11 metres (36 ft).

[3] On the northeast rim of the same caldera 12.8 kilometres (8.0 mi) to the east of the Bayonnaise Rocks is a submerged reef named Myōjin-shō (明神礁), which is a post-caldera cone with a depth of approximately 50 metres (160 ft).

The following day, an eruption killed 31 researchers and crewmen aboard the Maritime Safety Agency survey ship No.5 Kaiyo-Maru.

Located in the Kuroshio Current, the area has abundant sea life, and is popular with sports fishermen.