◆ PARALLAX

I have been diving at Yonaguni for three seasons and I think it is time someone laid out what the stone actually tells us. I am a geologist out of Yokohama and I have handled samples from the site. I want to make the case for the natural explanation -- not because it is boring, but because the evidence points that way.

The formation sits at about 25 metres depth off Okinawa. It is famous because of Masaaki Kimura's work in the early 90s reading it as a stepped monument. The photographs ARE striking. But the bedrock is Miocene sandstone, and sandstone fractures in very predictable ways: along bedding planes (the original layers) and vertical joints. The result is straight lines, right angles, flat surfaces. It looks carved. It is not. I have seen this pattern in sandstone all over the world.

The claim requires tool marks. I have looked. Under magnification the fracture surfaces are rough and weathered, without the striations a blade or stone tool leaves. The "steps" do not line up well enough for intentional levelling. This is not a letdown -- it is the real story. Has anyone done a detailed survey of the fracture geometry?

Kenji, thank you for a perspective that is not dismissive. I will push back gently on one point: tool marks vanish underwater. Coral, sediment, 5,000 years of erosion. If someone DID work this stone in the Jomon period, would we expect to see marks now, or would the stone have weathered smooth? That said, I agree on the jointing -- I have seen columnar basalt in Hokkaido that looks almost identical. So the question becomes: could a natural formation also have been reshaped or extended by human work? Could it be both?

Natural sandstone fracture. Next question. When you see straight lines and right angles in stone, the simplest explanation is geology, not masonry -- especially when the geologist on hand says it is geology. I don't understand why we need a lost civilisation to make Yonaguni interesting. The stone IS interesting. The burden of proof is on the people claiming construction: show me a tool, a worked edge that jointing can't explain, something. Until then I am with Kenji.

Both positions are too clean. Kenji is right that natural jointing explains most of what we see, and Occam's razor points to geology. BUT geology does not forbid human modification -- a culture could have found a naturally fractured formation and enhanced it, put a platform on top of "steps" that were already there. The real problem is the underwater photography: surge distorts scale, selective framing is easy, a flat surface that looks like a platform at one angle is a joint plane at another. We need systematic high-resolution mapping done skeptically. Until then I am with Kenji on the most likely explanation, but I am not comfortable dismissing the alternative entirely.

You are all wrong. Kenji is a geologist, sure, but he is trained to see only geology. The photographs do not lie. Those are STEPS. You don't get steps from jointing -- you get slopes, you get chaos. You don't get a STAIRCASE. There was a civilisation in the Pacific 10,000 years ago and Yonaguni is part of it, the lost history the academic world refuses to acknowledge. Mark my words, in ten years we will find artifacts at that site.

To the anonymous poster: I am not denying what you see. I am saying what you see is real geology, not hidden history. The "staircase" -- yes, it looks like one. Natural sandstone jointing PRODUCES staircases: regular vertical joints, regular horizontal bedding planes, and you get steps. It is not a coincidence, it is a feature of how the rock breaks. But you are right that appearance is what we are seeing -- 25 metres down in dim water with surge. We need better data: photogrammetry, 3D mapping, samples from every level. Then we can talk about what it really is. Until then the simplest explanation fits the data we have, and it is not boring.

I have taken maybe thirty divers down to Yonaguni. The site is complex. There are sections that look VERY regular -- the big southern platform, the right angles in the middle terrace. There are also sections that look chaotic and broken. If it was built, it is not finished or it is heavily damaged. If it is natural, the variation makes sense -- erosion works unevenly. What strikes me most is the scale. If this was built, the workforce and time were immense. So where are the satellite structures, the worker settlements, the tools? We have Jomon sites on Okinawa with clear artifacts. Why do we find NOTHING at Yonaguni except the formation itself? The absence of supporting evidence bothers me more than the presence of straight lines.

Hideo asks the right question. If Yonaguni is a monument, where is the culture around it -- the settlement pattern, the tool scatter, the burials? This is actually what makes me lean toward Kenji. The Jomon WERE capable of major construction, but we know it from sites where the evidence is comprehensive: structures, tools, settlements, the whole story. Yonaguni, by contrast, is just stone. Stone that could be natural.