As tales of Atlantis have long captured imaginations, a sunken city discovered off the coast of Japan has blurred the boundaries between myth and reality—and has raised controversy in scientific circles.
Ocean diving is an attraction off the coast of Yonaguni Island, part of the Ryukyu Arc, in Okinawa Prefecture. Yonaguni marks the end in a series of islands stretching from Kyushu, Japan’s southwesternmost main island, southwest almost to Taiwan.
Here, despite the island’s strong ocean currents, the prospect of swimming with hammerhead sharks lures underwater thrill seekers to submerged safaris, even during winter months.
But another attraction also beckons both adventurers and scientists to Yonaguni Island: ancient underwater ruins.
At the tip of the archipelago, 75 miles from Taiwan, a massive monolithic structure has sat submerged for thousands of years, just 200 yards off Yonaguni Island’s south coast. Not overly deep, the enormous rock mass lies at about 80 feet deep at its lowest; its pinnacle rises to only 15 feet below the waves.
This enigmatic formation has been dubbed the Yonaguni Monument.
While some have credited the Yonaguni Monument’s discovery in 1986 to local tourism official Kihachiro Aratake, who had been scouting the formation for good shark viewing spots, one of the names most closely associated with the monument is that of Japanese marine geologist Masaaki Kimura, from the University of the Ryukyus.
Mr. Kimura was among the first scientists to explore the city after the initial finding was made by Mr. Aratake. Believing it to be a man-made structure, the professor calls it an underwater Machu Picchu. He went so far as to propose that this submarine pyramid was the mythological lost continent of Mu—the Asian equivalent of Atlantis.
Soaring vertical walls encircle what is, essentially, a great oval, about 950 feet long, 390 feet wide, and 85 feet high, with its main face looking south-southeast. Irregular steps jut into the structure at different intervals, lending to its pyramidal look. Right angles, or near right angles, appear throughout. The Yonaguni Monument covers an area of 984 feet by 492 feet.
There are also, he believes, works of art: a large and impressive turtle sculpture; a giant human head gazing outward, like the ones on Easter Island; and what appear to be animals carved into the rock walls, some even bearing traces of paint on them.
It’s inconceivable that such phenomena were created by natural erosion, according to Mr. Kimura. He points out that there is no stone rubble at the base of the Yonaguni Monument, where pieces of structure would likely have fallen.
Although numerous scientists have corroborated Mr. Kimura’s assertion that the structure is artificial, skeptics in the scientific community have labeled his work pseudoarcheology. They tell a far different tale to explain its origins.
Most notably, geologist Robert Schoch, at Boston University, believes the Yonaguni ruins were formed naturally, explaining that its many apparent right angles and flat surfaces resulted from the type of rock they’re made out of. The local sandstone and mudstone layered deposits would easily separate and form flat, smooth surfaces.
Meanwhile, stratifications crisscrossing throughout this would cause fractures at natural right angles—though critics have pointed out that it’s unlikely right angles would appear so consistently at Yonaguni.
To account for the lack of debris lying at the foot of the monument, Mr. Schoch theorizes that strong ocean currents carried it away.
Anomalies that Mr. Kimura believes are arches with support posts were actually, Mr. Schoch holds, carved by eddies.
Lending weight to Mr. Schoch’s assertions, apparently, that the formation is natural, neither the Japanese Agency for Cultural Affairs nor the government of Okinawa Prefecture have paid the city much attention. Neither have sought to preserve or study the Yonaguni Monument.
Yet, despite the labels of “pseudoarcheology” and the skepticism about his findings, Mr. Kimura has continued his inquiries into what he calls the lost continent of Mu.
In order to date the sunken city, he has examined stalactites found in underwater caves, which he thinks sank with the city. These stalactites would have formed over thousands of years as minerals dripped from the cave ceiling and could not have been produced underwater. Before sinking, the caves must have long existed above ground.
Thus, the Yonaguni Monument might have sunk over 5,000 years ago. Other examinations have looked at coral growths on the rock walls and tectonic activity (a possible cause for its sinking) to pin down a date.
Yet with many a YouTube blogger and popular scientist siding with Mr. Kimura’s conclusions, even Mr. Schoch has conceded that Yonaguni isn’t pristine. As part of the underlying rock mass, it may have been terraformed by humans, he admits. It’s natural, but with a few touch-ups.
Despite all the bantering back and forth, we may never know its true origins. Yet the answers may still lie ripe for finding just feet below the waves.
