IT’S A MYSTERY WRAPPED IN A RIDDLE encased in an enigma, with the entire thing sitting within a big pile of rocks.
What exactly is going on under the sea at Yonaguni Island on the very western edge of the Japanese archipelago A lost civilisation Evidence of a cataclysmic earthquake back in the mists of time Or some interesting geology that looks nice but that’s as far as it goes.
Armed only with a sense of mild curiosity and several sets of open-circuit scuba gear, we set off to find out.
The latter part of that paragraph is not insignificant. Much as we trumpet rebreathers and celebrate momentous advances in diving technology that take us deeper for longer, there are certain places where a rebreather is a liability.
The undersea ruins off the island are shallow, battered by swell and surge, and swept by
mighty currents.
Rebreathers, for all their plus points, don’t like abrupt changes in depth very much, and can be tricky in shallow waters where the diver is being bounced about like an aquatic pin-ball.
We were entering a particularly violent piece of water, and as such the fancy boxes all stayed at home, bleeping with resentment in dark garages, and it was back to good old open circuit.

ANY CHANCE OF BEING lulled into a false sense of security by diving shallow while blowing bubbles were immediately cast to the four winds by Kevin Gurr.
“It’s these shallow dives that can catch you out,” he said during our first dive briefing. “You’ve often got rapid changes in ambient pressure in shallow water with swell pushing you up and down the water column.
“You’ve also got big currents here – next stop Taiwan if you get it wrong – and all manner of sharp, pointy bits of geology to spoil your afternoon.”
Prophetic words indeed. They say that there are no new mistakes in diving, only the old ones made by the new divers. Well this one was an old one made by an old diver – me.
Jumping in with a slight head cold and a malfunctioning (hired) BC, I found myself heading downwards at a moderately alarming rate, all the while parping through my nostrils so that my cheeks were distended like Louis Armstrong hitting a high note.
This was accompanied by an internal backing track akin to the Grimethorpe Colliery Brass Band from within my right ear.
Fortunately, hoving into view came the stocky figure of Andy Torbet, like some guardian angel on horse steroids, who arrested my downward trajectory, reinserted the hose into the back of my BC (a perished seal as it turned out), saluted, then swam off, presumably to wrestle a merman.
The depth of all this drama was about 5m.
All of this meant sitting out the diving the next day with a squeaky ear, with the rest of the team sitting in a group, whispering and pointing at me.
It just goes to show that, regardless of experience, depth or the kit you’re using, diving remains a sport where rules are rules, and woe betide those who take them lightly. A head cold and a dodgy BC are, as it turns out, a poor combination.

AS THE WEEK’S DIVING UNFOLDED, so the mystery of the ruins deepened.
Sadly, I can’t give too much away here, but suffice to say that it involved a massive earthquake that may not have happened, an ancient lost civilisation that may never have existed, a stalactite that might have been a figment of someone’s imagination, and two learned professors who couldn’t quite agree on anything.
The whole rationale of this series of projects is to find and explore great mysteries hidden beneath the sea around the world. Well, with this one we found a humdinger.
We were still talking about it on the last night of our stay, the team divided as to what we had been diving. Mind you, our generous and hospitable Japanese hosts had poured a fair amount of sake down our necks by this stage, so we were talking about quite a lot of things in a fairly animated way.
This ingress of mind-bogglingly powerful alcohol led later that evening to Dan Stevenson – doyenne of deepwater cameramen – getting locked out of his room in his pants, which led in turn to an Ealing Comedy set of misunderstandings and awkward situations.
And so we head off to our next mystery, leaving behind us a monument beneath the sea off a small island to the western edge of Japan.
Whether it is a monument to the power of nature or to the ingenuity of man, we may
never know.
All we do know is that in the wild waters off Yonaguni, a mysterious formation holds its secrets well.