Yonaguni
In 1985, Kihachiro Aratake, a dive tour operator in Yonaguni, Japan was scouting for a new site to view hammerhead sharks. He had dropped into the water on the southeast side of the small island, off a place called Arakawa Point, expecting to see the normal crevices, coral heads, and possibly an entrance to an underwater cave. What lay before him, however, was something that no one had viewed in thousands of years. In the amazingly clear water, stretching to the limits of visibility was a megalithic structure that appeared to be man-made with expansive terraces interrupted by large angular steps and bounded by flat vertical walls. Further investigation revealed symmetrical and angular channels, round holes 7 feet (2 meters) deep, and angular, raised platforms. The megalith was over 300 feet (100 meters) long.
Word of the discovery spread slowly outside Japan. It was almost a decade before information began to appear in various media, much of which could be characterized as on the anthropological fringe. These articles were creative and unique, although often lacking factual basis. The first serious scientific studies began in 1996 by Professor Masaaki Kimura, a geologist at the University of the Ryukyus on Okinawa. He and his teams surveyed and documented the original structure. Since that time, several others have been found, although divers arent allowed to visit them yet because of on-going surveys.
Professor Kimura provides a balance between the fringe that cite this as evidence for an advanced prehistoric civilization and the nay Sayers who assert that this apparently sculpted massive rock structure and the others are a result of natural phenomena only. He believes and can back up those beliefs with pretty convincing evidence that the structure is human modified. However, he has no illusions about the modernity of its creators.
Dives on the monument, which is what the Japanese call it, typically begin at its west end. The strategy is to swim down to a protected assembly area as fast as possible, and then, as a group, venture out onto the first terrace and into the incredibly strong east bound current. Maintaining ones position is difficult and sometimes impossible for more than a few seconds. Those with cameras must fin like crazy until they snap the shutter. Once they relax their kick, even a little, they slip backwards with the unseen torrent. Divers alternate between drifting across the terraces, and trying to find a hand hold or ducking into the lee of an angular outcropping to stop their drift. Handholds are often difficult to find because of the smoothness of the flat sandstone rock.
When diving the monument, there are essentially two routes to take. One is to continue down its entire length until angular features give way to an area that displays natural erosion characteristics. However, the erosion is from fresh rather than seawater. Because of the Ice Age, the level of the ocean was 130 feet (39 meters) lower ten thousand years ago. Eighteen thousand years ago it was 300 feet (100 meters) lower when the Northern Hemisphere had even a deeper covering of ice. The monument, which is 90 feet (27 meters) to the bottom would have been well above the tidal line back then and subject to the eroding forces of constantly running water. Knowing the sea levels gives us a crude means to approximate its age.
The other route is to launch midway down the monument, across a wide chasm, toward a smaller rock structure. On each end are carved steps and flat terraces. It's nowhere near as extensive as the monument, but interesting all the same.
The chasm is 90 feet (27 meters) deep. Investigating it, one finds both natural rock and some carved slabs that were apparently discarded from the structure. Near the edge of the monument is a cleared semicircle with a radius of about 20 feet (6 meters), which looks out-of-place with all the other rocks littering the bottom. One interesting feature is that there are nowhere near enough slabs to account for all the rock that would have had to be excised from the megalith. And there is no extraneous rock on any of the upper levels.
Other anomalies are scattered throughout. Near the assembly point is a four-foot (1.2 meter) high tunnel. The tunnel is part of a crude stone fence that would have presented a barrier to anyone seeking access to the monument from the south and west when it wasn't underwater. The fence itself is unique. It's made of limestone. According to Professor Kimura, there's no indigenous limestone in the area, meaning that someone long ago had to transport it there.
Once through the tunnel, a diver encounters twin stone pillars. The twin pillars are actually part of the same vertical rectangular rock, which somehow has been cut straight down the middle most of its length. Some think, and I'm among them, it was a work in progress and that the stone was being quarried for use somewhere else. Professor Kimura believes it may be a symbolic gateway to the structure itself.
The pillars are close to shore and their tops are no more than 10 to 15 feet below the crashing waves on the surface. This makes for a spectacular experience as one ascends up their length. On one of our dives, Aratake scrapped the fine coat of algae away from the rock and revealed what appeared to be a two-stroke glyph somewhat in the shape of the modern Chinese character for person . That the glyph could mean anything at all is highly speculative, but its there just the same. Similar etchings in stone are found up the coast in an area of shale and sandstone layering that is located above the tidal line.
On the top levels of the monument are stone platforms of different sizes. With average heights of 6 to 10 inches (15 to 25 cms) the rectangular and triangular shapes sit either attached to an existing rock face or independently on the terraces. On Okinawa, at low tide, in the shallows of Bolo Flats (Zanpa) and Maeda Flats you see the same type of raised rock. The stone around it was cut away years ago by local craftsmen for use as building materials.
Halfway down the length of monument, on the very top level, among the angular platforms and steps are two circular holes sitting side by side. They are each about 7 feet (2 meters) deep. They look like cisterns. Theres even a slot near the top where a cover could have gone.
At the absolute end of the monument, theres a large stone, somewhat oval in shape that looks completely out of place with the surrounding terrain, which is flat and devoid of other rock. It sits on an angular base. The tip of the rock points due north. To some it appears to be a sun rock, which ancients used to determine time of day.
It is the current that defines the diving on the monument. It is rare when it isnt running hard. The current is probably the reason for the discovery of the structure, itself. Nothing can take root on the monuments smooth surface. Sessile organisms are swept away as fast as they land. Otherwise, the rock face might be covered by generations of coral growth.
Divers at times must work in the heavy current and sometimes their solutions to this difficult condition is clever, although not without risk. Two Okinawa based divers were photographically documenting the long edges of some of the steps. Professor Kimura wanted evidence of wedge marks on the incised rock. While one took 60 percent overlapping shots of the rock face with a Nikonos Close-up Kit, the other held on to him with one hand and the corner of the step with the other. Unfortunately, an unexpected diver came flying around the corner in the current while they were working. His tank impacted squarely on the photographer's head, which still bears the scar.
Professor Kimura's thinking is that whoever was responsible for carving this structure, probably long before metal tools were in use, inserted wood wedges wrapped in some type of cloth or plant material into holes in the rock. They then applied water, which caused the wood to swell, and the stone was excised. On some parts of the structure, absolutely straight lines are etched into the top of the rock with narrow triangular holes spaced about a foot apart, where wedges could have been inserted.
After 15 years, Yonaguni's true nature remains a mystery. To dive the monument is to go back to an age we know nothing about. It is a remnant of a prehistoric time. It may have been an ancient shrine. There are some structural similarities to ruins found on Okinawa. It might have been a quarry. There's evidence of that also, although that leads to a further question of where did ancient people take the rock. It may have been a port. Some of the steps on the monument do not go to bottom, but end half way down the structure. Whatever it was, all we really know is that it's there. Anything else is speculation.
