I DON’T KNOW WHETHER it’s the 6000-mile journey to get here, the “one-shot” circumstances of a dive dictated by passing typhoons, or the building anticipation of visiting an enigmatic site I have long dreamt about, but this dive feels epic from the moment we emerge from an archway at 15m into wildly unfamiliar terrain.
My attention is captured by the matching megaliths wedged into a corner of the heavily striated sandstone walls. Similar in size, straight-edged and resting at the same angle, they don’t seem to belong. Their mute statement is that if they represent a geological accident, it’s a remarkable one.
I hover, trying to absorb everything, as Zac moves deeper to get the upward angles he needs for his photos. Despite an overcast sky there is enough late-afternoon light to create a moody roof to the stony space in which we find ourselves. A school of black jack hang just below waves breaking dramatically at the surface.
Above and from the west a dark shape approaches. I can’t make it out at first, despite the spectacular visibility, but then it resolves into an enormous humphead wrasse, gliding smoothly over to a vantage point, like an attendant when you enter an empty art gallery.

EVENTUALLY WE FOLLOW THE wall east, up and around a corner and onto a jaw-dropping series of clean-cut terraces, interconnected by geometric steps. This is the defining moment, the reason we’ve come all this way.
Hanging there in 30m vis, three divers dwarfed by what looks for all the world like alien architecture, we’re getting the full impact of Yonaguni’s Kaitei Iseki, which translates as “Underwater Ruins”.
It’s often called “Monyumento”, as well. We all know that Nature can create other-worldly structures, Ireland’s Giant’s Causeway being one example close to home. But right now it’s hard to accept that what we’re seeing could be anything but the work of Man – all those evenly spaced lines, perfect perpendiculars, wide ledges and stairways that might be negotiated with giant strides.
We’ve been blessed by the weather gods – this site is known for its strong currents, yet today it could hardly be calmer at depth. I take in more stepped surfaces stretching away below us. Surely humans must have intended this as some kind of grand design
We spend a long time surveying the Iseki terraces, trying to superimpose some sort of imaginary race of people onto them.
I say “we”, but in fact the third diver, our dive-guide Oki, has done this dive a thousand times, and when I ask him later if he believes the site is man-made he smiles and shakes his head. I think for Oki the novelty may just have worn off.

WE WANDER TOWARDS the upper part of the 100m-long main structure, where polished flat slabs of rock create new patterns, including an almost triangular depression like a shallow pool, what looks like a symmetrical carving evoking a flattened turtle and a road with stone walls. Imaginations are working at fever-pitch by now.
I think that’s it, we’re done, but we drift further east, and recall Oki’s briefing. The rock formations here are a contrast – we’re back to curves and swirls after all those perpendiculars and parallels – but it’s equally enigmatic.
Narrow fissures break into dramatic canyons into which we can swoop like computer-game fighters, and we’re bemused by the wide, deeply scoured hole in the rock that Oki called the Dome, but which looks more like the crater left by a giant ice-cream scoop.
All we need is a fleet of manta rays to come swooping in overhead to complete our sci-fi fantasy, but we must make do with lone-wolf parrotfish and triggerfish. Iseki Point has lived up to its promise.
The names “Ruins” or “Monument” might be making a big assumption, but it’s one I can now better understand.
The site was discovered by a local dive-guide 28 years ago. I first read about it in 1999 in a DIVER article by Okinawan writer Kenny Ehman. He had dived Iseki and interviewed Jacques Mayol, the freediving pioneer who, as a keen advocate of the theory that humans share a common ancestry with dolphins, had been happy to embrace the idea that the structure was man-made.
But I had been more impressed by the weight of evidence from Professor Masaaki Kimura at the University of the Ryukyus that this was some kind of ancient temple/fortress/harbour.
Despite all the debate, the fact that the site remains an enigma to this day explains its appeal to divers. Kimura’s theory has come under attack from some geologists, who say that in a zone of earthquakes and strong currents strange effects can occur in sandstones and mudstones, but it has yet to be shot down.
If we ignore the inevitable conjecture about extra-terrestrial visitors, the architectural hypothesis is that the structure was at least partially man-made from an existing rock formation as many as 10,000 years ago, and consigned to the sea as levels rose at least 6000 years ago (the oldest of Egypt’s Pyramids were built about 4500 years back).
There seems to be no record of a people in this part of the world capable of such an undertaking, but the guide who found the site claimed that aspects such as the steps bore a marked resemblance to the design of ancient tombs that can still be found around Yonaguni island.

WITH THE WEATHER CLOSING IN, we won’t be able to return to Iseki Point on this trip, but the memory of the dive is haunting. Next time I’d like to do it in the colder early months of the year, when hammerhead sharks visit. What a sight that would be over the ruins!
To say that Yonaguni island is quiet is an understatement. Our temporary home is Yoshimaru-so, a minshuku or traditional lodging house run by the island’s oldest dive centre, Yonaguni Diving Service.
We’re a short walk from the lighthouse that marks the westernmost point of this, Japan’s westernmost island. It’s a speck in the East China Sea, and on a clear day they say you can see Taiwan, 70 miles away.
Yonaguni is one of the 600-mile-long Ryukyu island chain. The Okinawa prefecture covers the western two-thirds of this chain, and we’re here at the invitation of the tourist board to sample all the good things Okinawa has to offer, especially under water.
We’re picking up the local ways, trying to remember to take our shoes off every time we enter a building. I needn’t have lugged my regs over – it’s strictly A-clamps here, and DIN fittings are unusual.
The food served at the dive centre is delicious but if you think of Japanese food as all sushi and sashimi, think again – Okinawan food is as distinctive as it’s addictive, and we see no sign of sushi.
They look blank when we ask for sake in a bar, too – awamory is the local liquor and it should be treated with caution.

IT’S EARLY OCTOBER, and although typhoon season usually peaks in September we’ve taken a chance – and unfortunately timed our visit to coincide with two late doozies.
As we dive in Yonaguni, Typhoon Phanfone is sweeping north over mainland Japan and causing fatalities. We’re so far west that all we’re getting is mild backwash and barely a breeze, but it’s enough to affect the diving.
The plan when we leave here is to move back in an easterly direction, first to dive Ishigaki, famed for its manta rays, and then the Kerama Islands, accessible from Okinawa’s capital Naha.
And as Phanfone wreaks its havoc, what will turn out to be the most violent storm of the year, Typhoon Vongfong, is moving up to replace it.
But before we head in their direction we have time for two more boat-dives in Yonaguni. The current is too strong to dive Iseki again, but Arakawa is a more sheltered, gently sloping wall nearby with
a surprising abundance of hard corals and small fish such as puffers, strings of masked butterflyfish and schools of blue wrasse and yellow-tail snapper, a scene to drift above and savour.
Family is another geological dive-site, and although Iseki is such a hard act to follow, I enjoy the ever-changing views.
We drift gently between ramparts of striated rock over a seabed strewn with small boulders, move along a wide passage between towering walls and emerge into a shallow basin, where an old net has snagged clumps of hard coral above.
We then enter a narrow gully where a stronger current picks us up and delivers us into a vast boulder-strewn area like a town square in the shadow of towering cliffs. There isn’t a huge amount of life on this dive, though once again a solitary humphead wrasse observes our passing, perhaps wondering what’s in it for us.

TWO DAYS LATER we’re getting ready to dive off Ishigaki island, an 80-mile flight further east and far bigger than Yonaguni.
The news is not good, however. Because of continuing ripples from the typhoon front, the showpiece Manta Scramble cleaning station is out of bounds, and the rays will have to manage without an audience. Disappointing for us; they can probably live with it.
We head instead for more sheltered Sakieda Bay, close to the remote dive centre, to carry out two shallow boat-dives, starting with Batfish Paradise.
Our guide is Akiko from the Umicoza Diving School, which has impressive facilities and, like the Yonaguni centre, a pleasant communal vibe about it and fine food being prepared for lunch.
From the dive-boat we can see a line of Coastguard vessels. They’re watching China. Seventy years after WW2, Japan still has no military of its own, only its volunteer Self-Defence Force, so it keeps a beady eye on its neighbours.
What it does have in Okinawa, however, are some 50,000 US armed-forces personnel, many of whom like to dive.

WE ROLL THROUGH fairly poor vis down to a series of coral outcrops at about 20m to watch large batfish being cleaned by attendant wrasse.
Batfish-cleaning is well worth watching, because they arrive in their normal silvery and black-barred garb and, once satisfied that the little wrasse have finished their work, suddenly assume a dramatic all-black appearance and take off vertically.
There isn’t a lot more to see, and the coral is scrappy, but the second very shallow dive at nearby Mash 2 turns out to be the prettiest of the trip. The name is a corruption of mushroom, from the healthy table corals that dominate this series of bommies. There are soft corals, such as vivid red gorgonians, but they are so occasional as to be startling.
Swarms of tiny golden, black, blue and yellow fish mingle with parrot and many varied pairs of butterflyfish. A moray eel weaves its way through the reef.
I’ve often seen trumpetfish swimming in close alignment with bigger fish – they do this while hunting, to blindside their prey – but here a bright yellow specimen is travelling as part of an oddly inseparable threesome with a leopard coral grouper and a single ornate butterflyfish. Not sure who’s using who.
We won’t see such an enthusiastic turn-out of fish again on this trip, as we edge closer to the typhoon corridor.

AND IT’S HERE that I have to be “straight down the line” and say that the diving at our final destination, the Kerama Islands, is not the greatest.
Our philosophy is to report on what we see, not on what we might have enjoyed the previous month, though I’m sure from the footage I’ve seen that the Keramas have far more to offer than we’ll witness.
As it is, the weather conditions mean that we’re right up against the odds, and the fact that we manage to get out at all, let alone for five dives, is testament to the determination of Tetsuro Nagasaka, who runs Honu Honu Divers in Okinawa’s bustling capital city Naha, and his skipper.
Tetsu, a veteran of Hawaiian diving and a powerful contender for most considerate dive-host ever, is determined to make our visit worthwhile.
With 2m waves once away from the Okinawa coast, it’s not surprising that few dive-boats are making the hour-long crossing to the Keramas on our first day in Naha. In fact Honu Honu’s skipper seems to be one of the few ready to give it a go, so keen Japanese divers from other centres are rolling up at his berth to hitch a ride – he has capacity for 30 divers, after all.
We get only halfway to our destination before the skipper declares that the seas are too rough. We have been rolling about a bit, though I’ve seen worse, but I realise that he’s more concerned about the journey back later.
We compromise by diving at nearby Nagannu, not so much an island as a big sandbar, but the dive sets the pattern for all five with Honu Honu, in that once we’re anchored in its lee the sea could hardly be calmer – though the sediment is always fairly well stirred up.
The first dive is a disappointing trawl over sandy seabeds and walls of scrubby coral and sponge looking for anything to photograph other than starfish and clams – in fact the best thing is a shoal of tiny squid scooting past on our ascent.
The Labyrinth at nearby Kamiyama is far more fun, because its maze of swim-throughs and canyons splashed with colour by corals and sponges houses another population of large batfish, again going through their wrasse wash-cycle and indifferent to our close approach.
Back on top of the Labyrinth, a mixed population of anemonefish, including tomatos and pinks, keep us entertained.
So Tuesday is good but not quite… will Wednesday prove better Typhoon Vongfong is hurrying north, and we’re already making plans to fly back to Tokyo a day early to ensure that we make our international connection, so this is our last diving day.
The skipper goes for broke, and though the waves are even bigger we manage to reach Zamami, one of the Kerama Islands, and tie in. But the first of three dives is the poorest of the trip, as we root around between sand-blown coral outcrops.
No sign of the signature turtles; we must settle for anemonefish and a lone moray eel. Zac does however come across a shell, a leftover from 1945’s Battle of Okinawa.
The “Typhoon of Steel”, the bloodiest WW2 conflict in the Pacific, raged for almost three months as the Allies tried to establish a foothold from which to invade the Japanese mainland and end the war.
Not long after the fighting in Okinawa ceased, two atomic bombs did that job.
Our arrival on the anchor at the Dragon Lady site is more promising, as we’re mobbed by inquisitive scissor-tail sergeants, emperors and pairs of butterflyfish – might some feeding have taken place here at times
The coral bommies are widely spaced out but more attractive here, if still a touch drab, but a population of parrotfish, trunkfish, damsels, lizardfish, snappers and fusiliers provide shifting clouds of colour around them.

DRAGON LADY AND TOMO have been no deeper than 15m, so we reverse the profile and finish with the deeper Tomo 2. It’s a step up, with far more staghorn corals and lots of small fish, including the attractive little humbug damselfish peculiar to Okinawa dancing over them. There are some brittlestars and gobies too, but we aren’t exactly spoilt for choice.
The skipper has to steer a wide circle through churning seas to keep us safe on the way back, and the journey takes twice as long as the hour it took to get out, and claims a few mal de mer victims too.
The diving hasn’t been epic, but we’re very grateful to Honu Honu for having experienced it. The typhoons have had an effect on the diving, but even if we had hair to ruffle, it would barely have been affected by the breeze – and we have fitted in far more dives than we expected.

WOULD I GO BACK to Okinawa Like a shot; it feels like unfinished business. I want to see the hammerheads at Iseki Point, the mantas in Ishigaki and what I hope are the real Kerama Islands.
But it’s far more than the diving, because Okinawan culture leaves its mark. It may not win prizes for architecture, but did I mention the food Look at the dive-centre websites – the noodle and its accompaniments loom large on every one.
The people we met were all courteous, generous and keen to please – to a fault. From dive pros making sure we got our dives in, to strangers who spoke no English going to extravagant lengths to give directions, you can’t argue with the welcome Okinawa provides.
Okinawans also regard themselves as a breed apart from mainland Japan. When
I raise the issue of commercial or “scientific” whaling with anyone, for example, I am told firmly that Okinawa does not buy into such practices.
Our hosts fill the gaps between dives with interesting outings and insights. An awamory distillery and sea-salt refinery in Yonaguni; charming Taketomi island with its traditional houses, deities and bullock-cart transport; food markets and live music; a dojo where we survived a martial arts session (karate comes from Okinawa, though our instructor Kevin came from Dorset); a restored castle that we literally ran around because our excellent guide was determined to complete a packed itinerary before our plane departed; and Okinawa Churaumi aquarium.

ONLY AT THE LATTER did Zac and I feel uncomfortable, watching three whale sharks circling among some 80 other species of marine animals – even though they were swimming round a fish-tank so vast, at 7500cu metres, that they call it “the Kuroshio Sea”.
With its 2ft-thick glass, like Iseki the aquarium seems a phenomenal human achievement, but it isn’t a sea, and what happens when the whale sharks outgrow even this outsize home
I won’t end on a negative note, however, because Okinawa is all about the positives. Because of distances, climate and language (though I was surprised how many signs and menus were in English) it may not be the easiest place for divers to plan a visit, but several tour operators have started offering it this year – get it right and you’ll be rewarded.
I did mention the food, didn’t I

FACTFILE
GETTING THERE BA from Heathrow to Narita Airport, Tokyo. Bus to Haneda Airport for domestic flights with Japan Airlines to Yonaguni via Naha, www.jal.com. No visa needed.
DIVING Yonaguni Diving Service (with accommodation), www.yonaguniyds.com. Umicoza Diving School, Ishigaki, www.umicoza.com. Honu Honu Divers, Naha, Okinawa, www.hhdivers.com.
ACCOMMODATION Vessel Hotel Ishigaki, www. vessel-hotel.jp. Mercure Okinawa Naha, www. mercure.com. Palm Royal Naha, palmroyal.co.jp
WHEN TO GO Some dive centres recommend June, when it’s hot but not too humid. September is associated with typhoons but October-November can be good. Winters are mild and December-March is the time for hammerheads. Water temperatures range from 29°C in summer to 21°C in winter.
HEALTH Hyperbaric chamber in Naha.
CURRENCY Yen. Credit cards are not always accepted in restaurants. Tips are not expected.
PRICES Dive Worldwide offers 15-day packages to Yonaguni, Ishigaki and the Kerama Islands from £3995pp for all flights, 12 nights’ accommodation (mostly half-board), some transfers and six days’ diving, www.diveworldwide. com. Inside Japan Tours has 14-night tours of the same locations in November and next March for £3130, with 21 dives, mainly half-board accommodation, internal flights and transfers, www.insidejapan tours.com
VISITOR INFORMATION Okinawa Convention & Visitors Bureau, www.ocvb.or.jp