Yonaguni Monument

Rock formation/Pelagic

Depth: 5–30 mLevel: Advanced Open WaterDecember-April (hammerheads)

A rock formation of some 100 by 60 m and about 25 m high, with terraces, vertical walls and right angles unusual on the seabed. It was discovered in 1986 by Kihachiro Aratake, of the Yonaguni tourism association, while he was looking for a good spot to watch hammerhead sharks.

Depth

5–30 m

Recommended level

Advanced Open Water

Average visibility

20 m

Did you know?

Its origin is still disputed and that should be reported honestly: the marine geologist Masaaki Kimura, of the University of the Ryukyus, maintains after two decades of study that it was carved when the area was above water, around 10,000 years ago. Other specialists, such as Robert Schoch and Patrick D. Nunn, hold that it is entirely natural: the sandstone is crossed by parallel vertical joints that fracture the rock into rectangular blocks, and Yonaguni lies in a seismic region. There are similar stepped formations on land, at Sanninudai.

Sources consulted: Wikipedia (Yonaguni Monument / Ogasawara National Park); Japan National Tourism Organization; IUCN World Heritage Outlook; Atlas Obscura; enjyu-japan.travel

Location

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