The Yonaguni Monument Is Considered Japan’s ‘Atlantis’

Samantha Franco
Photo Credit: Melkov / Wikimedia Commons CC0
Photo Credit: Melkov / Wikimedia Commons CC0

The Yonaguni Monument, also known as the Yonaguni Submarine Ruins and Japan’s ‘Atlantis,’ has divided scholars since its discovery. The strange rock formation opens the floor for discussion about whether it was formed by natural processes or built at the hands of humans from an ancient world. However, neither the Japanese Agency for Cultural Affairs nor the government of Okinawa Prefecture have identified the site as a place of historical importance, so little research has been carried out. As such, a lack of clarity surrounds the monument. Whether it is natural or manmade, it attracts many divers to the area hoping to catch a glimpse of its unique shapes.

It was first discovered in 1986

The formation was first discovered by Kihachiro Aratake, a director of a local tourism association, in 1986. He was diving in the sea of Yonaguni searching for a spot where he could observe hammerhead sharks when he accidentally stumbled upon the rock formation. Yonaguni is a popular place for diving in the winter thanks to its abundance of hammerhead sharks, so Aratake was likely shocked to have come across something else entirely. Not knowing what he was looking at, he took photographs of the structure for later analysis.

underwater stone steps
The underwater formation or ruin called “The Turtle” at Yonaguni, Ryukyu Islands. (Photo Credit: Masahiro Kaji / Wikimedia Commons CC BY-SA 4.0)

Located below Arakawabana cliff in the southernmost part of the Ryukyu Islands some 100 kilometers east of Taiwan, the rock formation stretches more than 165 feet long and about 65 feet wide. It is made of fine sandstone and mudrock. Most of the rock is connected to the underlying mass beneath it, rather than being a freestanding collection of stones.

Kimura believes it is an artificial formation

Following its discovery, Masaaki Kimura, a marine geology and seismology professor at the University of Ryukyus, began a deep study of the formation. He collected data and recorded the characteristics of the monument, coming to a conclusion that has been highly contested by other professionals across multiple fields. After over 15 years of study, Kimura believes that the structure is manmade, and has referred to it as the ‘Japanese Atlantis.’

A model of the Yonaguni monument
A model of the Yonaguni Monument. (Photo Credit: Liangtai Lin / Flickr CC BY 2.0)

Kimura and other people in this camp believe that the Yonaguni monument is evidence of a lost ancient civilization, possibly part of the lost continent of Mu, which vanished underwater after a severe hurricane. They believe it is a manmade stepped monolith, with various identifiable points within it that include a pyramid, roads, monuments, castles, and a stadium.

Kimura has dated the structure multiple times

In his first estimation, Kimura stated that the structure dates back at least 10,000 years. This would have been during a period when the area was not submerged underwater, agreeing with the theory that it could have been part of the continent of Mu. However, during a report given by Kimura at the 21st Pacific Science Congress in 2007, he changed this estimate to date the site to 2,000 to 3,000 years ago. This was a time when sea levels were relatively close to where they are today.

Underwater stone steps
An object that looks like giant stair, on the Main Terrace of Yonaguni Monument, underwater near Yonaguni Island, Japan. (Photo Credit: Melkov / Wikimedia Commons CC0)

Kimura placed the explanation for the change on the fact that tectonic activity in the area had caused the site to become submerged under the sea. He also maintained that it once belonged to the ancient Yamatai civilization.

While some agree that there are features that suggest natural origins, the concentration of this kind of natural formation in such a confined space is highly unlikely. Additionally, the symmetrical shapes of the structure suggest that human craftsmanship played a hand in creating the formation. They also feel that the lack of loose stones within the structure proves that it could not have been solely naturally formed, as loose blocks would be present as a result of natural erosion and fracturing.

An expedition to the Yonaguni monument

Opposers of Kimura’s theory of the Yonaguni monument call it pseudoarchaeology, indicating an unscientific process of data gathering and analytical processes.

Divers in front of a massive vertical stone underwater.
Divers touching the monoliths to provide a sense of scale to the Yonaguni Monument. (Photo Credit: Melkov / Wikimedia Commons CC0)

In 1997, Yasuo Watanabe, a Japanese industrialist, sponsored an expedition to the Yonaguni Monument. This was an informal expedition, with a team that included pseudoarchaeology writers John Anthony West and Graham Hancock, as well as geologist and fringe theorist Robert Schoch, photographer Santha Faiia, and a couple of film crews to capture the informal dive. Following this expedition, many involved concluded that the formation was naturally formed without human interference.

Skeptics say it was formed naturally

Those who fall into this camp say that the natural geological processes that occur underwater are responsible for the formation of the Yonaguni Monument. They posit that underwater currents, which are strong in the area, as well as tectonic activity that also occurs frequently in the area, are behind the creation of the rock formation. When it comes to the symmetry of the rock shapes, skeptics say that they are coincidental and don’t necessarily suggest any kind of human interference.

An aerial view of an underwater rock formation with multiple levels.
The triangle pool identified as part of the Yonaguni Monument. (Photo Credit: Melkov / Wikimedia Commons CC0)

Schoch has been a vocal opposer of Kimura’s theory, saying that his own observation of the sandstones that make up the formation “contain numerous well-defined, parallel bedding planes along which the layers easily separate. The rocks of this group are also criss-crossed by numerous sets of parallel, vertically oriented joints in the rock. These joints are natural, parallel fractures by which the rectangular formations seen in the area likely formed. Yonaguni lies in an earthquake-prone region; such earthquakes tend to fracture the rocks in a regular manner.”

They say Kimura didn’t do enough research before forming his theory

Schoch explains that there are similar formations found underwater in the northeast coast of Yonaguni, which support his claim that this particular monument was likely naturally formed. West agreed with Schoch that the site was naturally formed, saying that Kimura “had not looked carefully enough at the natural processes at work.”

Underwater rocks line either side of a path.
To the right of the “Loop Road” is the Yonaguni Monument itself, and to the left is the “Retaining Wall,” which is a set of big boulders neatly arranged along the “road’s” edge. (Photo Credit: Melkov / Wikimedia Commons CC0)

In Kimura’s observations, he identified “drawings” on the surfaces of the rocks, which Schoch has reduced to natural scratches caused by underwater currents. Additionally, as for the “walls” that Kimura identifies, Schoch has called them natural horizontal platforms that fell into place when the rock below eroded away.

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Despite all of the chatter surrounding the Yonaguni monument, it still remains definitively unclear whether it was naturally formed or was built by an ancient civilization that came long before us.