The Tunnel and The Megaliths
On our second dive we visited the twin megaliths, weighing approximately 100 tonnes each, stacked side by side like two huge slices of toast in a west-facing alcove in the northwest corner of the main monument. As noted earlier, a prime side-on view of these hulking rectangular blocks unfolds from the top of the curved sloping ramp explored on the first dive. And we’ve seen that the ramp appears to have been cut down (either by natural or human forces) between two parallel walls out of a pre-existing rocky knoll.
The knoll in turn co-joins other massive, heavily overgrown structures presumed to be outcrops of natural bedrock which form an almost continuous barricade, three metres high and five metres thick, thrown out in a loose semi-circle in front of the megaliths - all at roughly 15-18 metres water depth. The barricade is penetrated at only one point, and there only by a narrow tunnel a little over a metre wide and about a metre and a half high through which a scuba diver swimming horizontally may pass comfortably.
The tunnel itself looks “built” - as opposed to rock-hewn like so much else at Yonaguni - in the sense that each of its sides consists of two courses of huge blocks separated by straight, clearly demarcated, matching joints. There is insufficient room to stand up within the tunnel, indeed barely enough even to crouch, so when it was above water 8000 or 10,000 years ago any human entering it would have been obliged to crawl through to the other side. What is striking then, as soon as you emerge, is the way in which you now find yourself directly opposite and beneath the twin megaliths which, from this angle, rear edge-on above you like the paired sarsens at Stonehenge or the pair of upright granite megaliths worshipped since antiquity in Japan’s Ena region as “the sacred rock deity, the object of worship” (see Chapter 25).
The swim ahead to the base of the megaliths is a matter of 20 metres and you observe immediately at this point that they do not stand on the sea-bed but are elevated about two metres above it, with their bases resting on a platform of boulders, and framed in a cleft. The side of the cleft to your right is formed by the rear corner of the main terraced monument; the side to your left is formed by a lower ridge of rock which also shows signs, though to a lesser degree, of terracing. Both megaliths slope backwards at the same angle against the cleft and both are the same height (just over six metres). The megalith to the right is distinctly thicker than its otherwise near “twin” to the left. Both megaliths taper at top and bottom so that the gap between them, about the width of a fist at the midpoint, is not constant. Although roughened, eroded and pitted with innumerable sea-urchin holes, the megaliths can still be recognised as essentially symmetrical blocks, all the faces of which appear originally to have been smoothed off to match - although, again, whether the process that brought this effect about was entirely natural, or at some point involved the input of human skill and labour, remains thus far a matter of a very few contradictory professional opinions and no facts.
I allowed myself to float up, towards the surface, along the slope of the megaliths, resting my hand in the gap between them as a guide. The light was good and I could see right into the gap; looking back at me from the far recesses a plump red fish eyed me with horror and hoped that I would go away.
As I neared the top of the megaliths, submerged under just five metres of water, I began to feel the ferocious wash of waves pounding against the surrounding rocks. I clung on and for a few moments allowed my body to be tugged back and forth by the swell. Enshrouded in a cloud of foam I could see the northwest corner of the main monument still rising above me the final few metres towards the surface.
After the dive Wolf and I again discussed what we had seen and quite soon, after some fruitless trading of opinion, our argument began to focus around a single - potentially decisive - issue. Had these very striking parallel megaliths been quarried, shaped and lowered into position beside the northwest corner of the main monument by human beings? Or had they arrived there through wholly natural processes?
I had drawn another rough sketch map to which I now pointed:
GH: There's the two blocks, and we see above them here, not very high above them, the mass of the structure which leads round to Iseki Point. Explain to me how those blocks got there.
WOLF: Okay. You have seen lots of blocks fallen down -
GH: All over the place.
WOLF: On the shoreline we saw from the ship -
GH: Many fallen blocks, yes.
WOLF: - lots of blocks have fallen down from higher parts -
WOLF: - from beddings which have been broken, which were harder than the underlying layers; because what happens is that you get an an undercurving and undercutting of softer material under harder banks. So in my belief, these two blocks have been once one block of two sandstone banks, with either softer material in between or nothing in between, just only the bedding limits.
GH: Well, I want to know how they got where they are now.
WOLF: Okay. My opinion is that these blocks have fallen down from a very, very high level, relative to their present situation.
GH: But no high point overlooks them. You would have to go back -
GH: Well, yes, fair enough, nowadays. Nowadays you would have to go back in a northward direction some 50 or 60 meters, maybe more, horizontally, before you reached the cliff.
WOLF: Right, that's clear for nowadays. I'm talking about a time range of at least 10,000 years maybe more.
GH: That we agree on.
WOLF: So then there could have been places of a higher position from which these stones could have fallen down.
GH: So you are hypothesizing a pre-existing higher place from which these fell?
WOLF: What I'm hypothesizing is that they have fallen down, so and this must have happened from a, let's say, sufficiently higher place. So what this may be then -
GH: Do you agree with me that this place[Indicates top of northwest corner of main monument 3-4 metres above top of megaliths] is not sufficiently high? The place we see immediately above it now?
WOLF: I don't have it in mind clearly, so I just can imagine from -
GH: But do you remember when we came to the top of these columns, of these blocks we were coming close to the surface. You could feel the swell hitting you quite hard and the foam above your head very strong. In fact, it's like looking into clouds almost. And you can see the mass of the rock above you, probably not more than another four metres above, and you're going to hit the surface there.
WOLF: Yes, I would think this would not be high enough.
GH: So we need a hypothetical high place to do it?
GH: And I, of course, need a hypothetical civilisation -
GH: - capable of moving it here.
WOLF: Yes, of course, yes, yes no doubt about it.
GH: So we have two hypotheticals there.
WOLF: I'm not going to discuss any presence or absence of any civilisation because that's not my field
But the problem I feel - and shall continue to feel - is that the very odd combination of major stone structures lying underwater at Yonaguni, and the very odd combinations of characteristics found within every one of those structures, simply cannot be said to have been properly evaluated until the possible “presence or absence” of a civilisation - specifically the Jomon - has been very thoroughly taken into account.