It's an inauspicious start. An overcast afternoon, with heavy clouds threatening rain. We follow a breadcrumb-trail of hand-painted wooden signs through nameless seaside villages, along ever-narrowing roads flanked by low walls bearing Chinese-looking lions called shisa. I feel like Alice falling down the rabbit hole - then we drive down a ramp and into an underground car park.

It's an odd first impression but the perfect introduction, I soon realise, to a luxury hotel that marches to the beat of its own drum: Hyakuna Garan, on the south-east coast of Okinawa's main island.

"'Where is the entrance?' That's the question we're asked most often by guests," says manager Norihiko Masuda, who joins us for a welcome drink of hibiscus tea on the lobby verandah. He has the quietly amused demeanour of a Zen master - or a karate sensei. Indeed, it was karate, which originated in Okinawa, that brought Tokyo-born Masuda, a long-time karate practitioner, here 17 years ago.

He has been with Hyakuna Garan since it opened in April 2012 and understands that guests might be confused to find a windowless, fortress-like facade instead of a sweeping driveway and wide-open doors. The intention, he explains, is to surprise. Like this: you enter through a small gate at street level (or the car park) not quite knowing where you are until, at last, you're struck by the natural spectacle of the hotel's location, halfway up a limestone cliff and as close to the ocean as you can be without getting wet. "It's simple: please, have a seat, look at the ocean, relax," he says.

It's not a Zen Buddhist or temple hotel, he insists, before adding that, in any case, "Zen, or karate, is just life, it's everything". But you don't have to be at Hyakuna Garan long to realise that Zen - or rather a simple ethic of peaceful spirituality - is in every thoughtful detail.

Its design was inspired by temples rather than luxury hotels. Its name comes from the name of the local village and the Japanese word "garan", meaning "temple". Descriptions in English on the hotel's website read like haiku: "Among the pure silence, the stone Buddha image greets the guests gently"; and "Surrounded by trees, the mansion [hotel] is drifted with the pure air and the clean wind, which will enrich your mind and body".

In addition to the white towelling robe in my room, there are two outfits for wearing around the hotel. Not yukata (lightweight kimonos worn by guests in ryokan); they're more like pyjamas: a white pair for sleeping and a black pair for lounging, the latter based on the indigo-blue workwear called samue worn by Japanese monks.

There are no daily yoga classes, meditation sessions, karate lessons or other activities (though there is a spa); instead, the hotel fosters a feeling of calm in other ways.

Wooden floors throughout encourage awareness (because walking unconsciously can be noisy and disturb others, Masuda says). Manual light switches bring you in direct contact with your surroundings. "We like guests to step out of regular time and into a more mindful appreciation of time," Masuda says, "but it's up to the guests - we just open the door."

One of the hotel's most impressive features is an enormous empty "Zen room": a 40-tatami-mat meditation space with black cushions (called zabuton in Zen) neatly stacked at one end and a view of the sea through the trees at the other. "There is nothing," the website says. "As for anything, it is unnecessary. Here is such a space. Please enter barefoot."

If Hyakuna Garan has a mission, it is to showcase the best of Okinawa, from its natural beauty and its food to its architecture and relaxed way of life. The walls are Ryukyu limestone, for instance, with terracotta roofs like traditional Okinawan houses. An art gallery corridor is lined with commissioned portraits of historical figures in the Ryukyu Kingdom (which became Japanese Okinawa in 1879). And two of the most sacred sites in Okinawa are just down the road: a natural stone tunnel called Sefa-Utaki, and Kudaka Island, both of which are significant in the creation stories of the first islanders.

Dinner, as well as breakfast, is included in the room rate. There are no menus, however. Guests can request whatever they would like to eat or leave it up to the Okinawan head chef, and one night you'll be treated to a 12-course extravaganza of Okinawan specialties, artful creations ranging from the simple to the sublime, including the freshest sashimi you've ever tasted; various types of local seaweed, vegetables and salts; Okinawa's best beef (from Ishigaki Island, an hour's flight away); and dessert delicacies such as sweet potato macarons and dragonfruit sorbet - all served in locally made Ryukyu glass, ceramic and lacquerware dishes.

Returning to my room after dinner, it strikes me that Hyakuna Garan is most beautiful at night, when walking the long verandahs is like strolling the decks of an ocean liner, with its footlights, railings and glowing windows facing the moonlit sea.

It's never too late for surprises here; as I open my door, I see that my room is as messy as I'd left it. No turndown service? It's just another way to let guests be. "It's just a hotel rule [in most hotels] that makes staff want to clean up after guests," Masuda explains later. You can request housekeeping at any time; otherwise, you won't be disturbed.

The next morning I get up early, put on my samue and pad down to the Zen room. There's no one else around. It's completely silent but for the natural sounds of wind and waves. I put a zabuton on the tatami floor and sit on it - listening to the sea, breathing in and out, feeling the warm morning air on my face, enjoying the sweet aroma of tatami mats, remembering something Masuda had told me the day before: "We like our guests to experience with the eye, nose, mouth, ear and skin."

The sun comes up, pinking the sky. Fishing boats putter out into the channel in front of the hotel. For all its elegance and contemporary comfort, this is Hyakuna Garan's most precious offering: tranquillity aplenty in a quiet coastal setting.

This being Japan, of course there's an onsen (bathing area) - with a twist. After breakfast I take the lift to the roof of the hotel and follow a path of stepping stones to one of six red-roofed private bath houses designed to resemble a

13th-century Okinawan village. Each one has a tatami room, a deck equipped with sun lounges and an outdoor bath and shower, and a low doorway - which makes you bow as you enter and ensures that when you stand up again you get the full impact of the view. Up here, unbroken by rooflines or windows, it's even more spectacular than it is elsewhere in the hotel.

Someone has kindly filled the bath for me, so after showering (Japanese bath rules still apply) I lower myself in, and exhale. Lying neck-deep in the warm water under a blue Okinawan sky, wearing a hat against the tropical sun, looking through the railings at the East China Sea and listening to high-tide waves far below, I finally get what Masuda has been saying all along. It is simple: there's the sea. Look, listen, be here.

Sometimes we just need reminding that the greatest luxuries of all are time and space.

Louise Southerden was a guest of Japan Airlines, Okinawa Convention and Visitor Bureau and Hyakuna Garan.

FAST FACTS

Getting there Japan Airlines has a fare to Okinawa from Sydney for $1368 return, including taxes. Fly to Tokyo (9hr 15min) then to Naha, Okinawa (2hr). See jal.com.au. From Naha airport, it's about 35 minutes by car to Hyakuna Garan; a taxi there costs about 5000 yen ($52). Alternatively, you can rent a car at Naha airport. See okinawastory.jp/en.

Staying there Hyakuna Garan has 13 rooms and two suites, all with ocean views. Rooms cost 50,000 yen a person; suites cost 75,000 yen a person. The entire hotel can be rented out for up to 30 people for 1.5 million yen a night. Rates include breakfast, dinner and use of the open-air bath-houses. See hyakunagaran.com.

More information visitokinawa.jp