What better place to master a headstand than at the base of a sacred mountain with a Buddhist yoga instructor?

Despite being quite a keen yogi, I've always been nervous about trying the pose. But my teacher, Thuy, patiently demonstrates the steps and calmly guides me through them.

The tranquillity of the Yen Tu Mountain must have worked its magic on me, because I'm able to lift my legs for a few moments, while balancing upside down with my hands either side of my head.

A modern introduction to an ancient world

My feat is carried out at the newly-opened Legacy Yen Tu MGallery hotel, in the Quang Ninh Province of northern Vietnam, built on Yen Tu Mountain - a sacred site considered to be the cradle of Buddhism in Vietnam.

It's revered as the place where King Tran Nhan Tong (who reigned from 1279-1293) achieved enlightenment after he renounced his earthly possessions and established Truc Lam, the Vietnamese school of Zen Buddhism.

The mountain is rich in natural beauty. Winding stone paths, dotted with striking temples, snake up through the dense forest and offer spectacular views.

The 133-room hotel is part of a 2.8 hectare complex, which was inspired by the story of the Buddha King. It's built in the style of a 13th century Vietnamese village, a quaint collection of buildings with low-slung tiled roofs, as well as shops and market stalls selling local arts and crafts, including woven baskets and delicious ginger sweets, and a hostel for travellers on a budget.

Designed by Bangkok-based architect Bill Bensley, whose other works include the Oberoi Vilas projects in India and Four Seasons' award-winning resorts in Thailand, it nestles in a valley at the foot of the slopes and focuses on spirituality and tranquillity.

"It's all about the tomb, everything points towards it," Bill explains, as he proudly takes me on a tour of his creation. He is referring to a sacred site halfway up the mountain, which is said to contain some of the king's remains.

A place to relax and reconnect

Strolling through the tranquil cloistered hallways, it's easy to imagine you're in an ancient monastery. The property is even more magical when it rains and the secluded courtyards are filled with the sound of drumming water.

There's a calm atmosphere and stillness flowing around every corner. Within hours of arriving, I can feel the worries of everyday life slipping away.

"Yen Tu means journey back into yourself," adds a beaming Bill.

When it's completed, the hotel will include a swimming pool and wellness centre, offering guests meditation, herbal steams and baths, and back scrubs.

I get another taste of spirituality when I join a singing-bowl meditation class. It's a wonderful moment when I feel my metal bowl vibrating in my hands as I chant "om" while sitting cross-legged in a pillared hall.

Telling the story

Every aspect of the hotel has been meticulously designed in keeping with the traditions of the religion. A huge portrait of the majestic, pink-robed Tiger Princess, one of the king's concubines, dominates a wall of the bar.

Many of the rooms have high ceilings and all are fitted with solid wooden sliding shutters and traditional rice husk walls.

In the village square, a procession of dancers dressed as lions, birds and dragons put on a mesmerising display of music and dance.

I'm even invited to join in and manage to do the traditional bamboo dance, where participants run over a line of poles as they are tapped and clapped in rhythm to the music.

At the end of the evening, I'm presented with an array of exotic fruits which have been carved into the designs of fish, porcupines and even a puppy.

Climbing Yen Tu

Maximum use has also been made of the environment. I spend a quiet moment sat at a granite table on my balcony, overwhelmed by the lush green mountain slopes across the valley.

Swathed in wisps of clouds, the 1,086-metre summit of Yen Tu Mountain is beckoning me. It's possible to walk, but I take the easier option of gliding above the treetops in a cable car.

The first stop, between the lower and upper cable cars and around halfway to the top, is a sacred stone shrine, which is said to contain relics of the Buddha King. Gnarled trees form a ring around the site and lean protectively over the spot, giving the place a slightly eerie atmosphere. Offerings of food, fruit and flowers can be seen nestling in ancient nooks within the stone monuments.

The next stop is the Mot Mai - or 'one roof' - Pagoda which clings precariously to the side of the mountain. Half of the structure consists of a natural cave filled with carved statues of animals and gods that date back hundreds of years. There is a mountain spring in one corner and it's said that anyone who drinks the water will be granted one wish.

After my second cable car ride, there is a short hike through dense bamboo forest with glimpses of the spectacular scenery below. My final stop is a towering golden statue of the Buddha King, just below the summit. The effigy is flanked by a huge bronze gong and bell, which are used during religious ceremonies and said to bring good luck if you touch them.

Where else can you go?

Although situated a few hours along the well-trodden route from Hanoi to Halong Bay, Yen Tu Mountain has yet to be discovered by international tourists. But it works perfectly in combination with the two better known bucket-list destinations.

It's a contrast to the hectic streets of Hanoi, teeming with scooters and lined with cramped bazaars. I enjoy exploring the narrow streets of the Old Quarter, each one filled with a different speciality, from shoes and bags to door handles.

The grand elegance of the colonial-era Legend Metropole Hotel in the French Quarter offers the perfect place to unwind after a busy day of sightseeing.

My final destination is the towering limestone formations of Halong Bay. Kayaking is the ideal way to get up close to the dramatic peaks and I feel like a proper explorer paddling through narrow gullies and caves. Another unique way to see the Unesco World Heritage Site is from a 12-seater seaplane.

It's only with the bird's-eye view that I realise the magnificent scale of the bay, with rows of lush green peaks stretching into the horizon. Remote fishing villages can be seen floating on rafts in hidden nooks, while majestic cruise ships glide through the turquoise waters.

After a surprisingly cushioned landing, it is time to say goodbye to this enchanting country. I leave Vietnam feeling enlightened and in touch with my inner peace.

How to get there

Vietnam Airlines (vietnamairlines.com) operates the UK's only non-stop scheduled flights to Vietnam, with daily Dreamliner services from Heathrow to Hanoi or Ho Chi Minh City. Returns from £464 per person in Economy; £938 in Premium Economy; and £1,818 in Business Class.

Experience Travel Group (020 3355 7873; experiencetravelgroup.com) offers a four-night package including stays at the Sofitel Legend Metropole Hanoi, Legacy Yen Tu - MGallery by Sofitel, and the Paradise Luxury Halong Bay Cruise, plus return Vietnam Airlines flights from £1,746 per person.