Tempted by the vegetarian delights of Buddhist cuisine, Rhiannon Batten heads for the hilltop town of Koya-san
The Japanese have a specific phrase for those times when you insist you can't manage so much as another grain of rice by the end of a main course but then miraculously manage to scoff your way through an enormous pudding. And, with traditional Japanese meals tending to come in a series of small but perfectly presented dishes rather than a single huge plate, betsu bara, which roughly translates as finding your second stomach, comes into play pretty often.

Even at the country's Buddhist temples, where menus are based around such strict traditional principles that pungent foods like garlic and onions - as well as all meat - are forbidden, the food offered to guests is surprisingly lavish. The ingredients might sound a bit frugal but what they lack in range the chefs make up for in invention. What they can't do with a pickle - or that other great temple staple, tofu - probably can't be done at all. As you find out if you visit Koya-san, Japan's foremost temple town.

Perched on a hilltop 90 minutes train and cable car ride south of Osaka and surrounded by persimmon, mandarin, bamboo and rice plantations, Koya- san was founded over 1,000 years ago by the Shingon Buddhist priest, Kukai. Today Kukai's shrine marks the focal point of Okuno-in, an eerie collection of about 200,000 tombstones set amongst an ancient cedar forest. As well as the glossy black lacquer, gilt and gravel gardens of the stunning main temples and stupa, this is what most visitors to the town come to see. For them, Kukai isn't dead but merely in eternal meditation, able to hear their prayers.

Around 5,000 people now live and work in the town, either in one of the remaining 117 temples or in the shops, restaurants, schools and other amenities that have grown up around them. The visitors, meanwhile, get to choose from 53 shukubo, or temple lodgings. Keen to try the region's celebrated Shojin-ryori, or vegetarian temple food, I checked into one, Muryoko-in.

Here, the monastic rituals of prayer, cleaning and meditation that start each day before 6am are broken by two meals of soup, beans, rice, zingy citrus-flecked pickles and tofu in myriad guises - flavoured with sesame and served with peppery wasabi, dipped in batter and served as tempura or baked firm with sugar. While I was still tempted to join some of the temple's Western monks in nipping out for a breakfast of coffee and croissants at the posh local bakery, the tofu here was several steps up from the chewy grey goo back home. Fresh, white and creamy, it was somewhere between a mild ricotta and a wobbly, set yoghurt.

But if the diet sounds a bit wholesome, temple life has its compensations. Koya-san's monks and nuns are free to get married, drink beer and sake and even wander down to the local spa on their days off. Deciding to follow suit, I tagged along with one of Muryokoin's priests, Kurt, a gregarious Swiss monk with a penchant for Issey Miyake clothes. Married to a Japanese woman he met while living in Italy, he has been a member of the Koya-san community for seven years, and a minor celebrity since he started fitting in tours for journalists and TV crews around his temple duties.

After an efficiently Swiss-style tour of the temples, Kurt ordered a taxi and we sped off through pine-filled gorges under a setting sun to the local onsen, or hot spa. Naked, and feeling vulnerably British as I edged a toe into the water, I almost tripped right into the steaming water as a shout came over the wall behind me. "How is it?" yelled Kurt, enthusiastically. "You see the view of the garden? It's lovely in spring time when the cherry blossom is out". Reassured that he wasn't coming over to my pool as a mellow whistle drifted across from the other side of the wall, I began to relax, sliding slowly into the water and letting the heat soak through me.

When I finally clambered out, I marvelled at how soft my skin felt - and how like marshmallow my brain was. It was easy to appreciate why onsens are so popular in Japan. They are as intrinsic a part of life as pubs are in Britain. Most people see going to an onsen as part of their regular routine.

One of the best for visitors is Sumiya-Kihouan, an upmarket ryokan, or traditional Japanese inn, set in the countryside outside Kyoto. You get there by something called the Romantic Train (a scenic chug past the jade-coloured water and the dramatic, foliage-fringed gorges of the west of the city). Then, there's the building itself. Good enough for John Lennon, who visited in the Seventies, its rooms go the whole Japanese hog, with simple tatami mat floors, sliding paper doors and neatly kimono'd staff to make your futon, serve your dinner and make sure you don't get lost on your way down to the baths.

Sumiya-Kihouan is a lesson in calm, with an elegant stone communal bath. More intrepid guests can also wander through the surrounding forest to another small series of organic-looking pools where the water is a searing 42 degrees. There was another surprise. Koya-san's onsen may have been the perfect antidote to the chilly mountain weather but at Sumiya-Kihouan I was given my own private outdoor tub, into which I could sink in total seclusion.

The private bath wasn't nearly as indulgent as the food, though, which is based on seasonal and local specialities. Sumiya-Kihouan offers an altogether more upmarket version of the healthy eating experience, served in a steady stream of about 15 courses. Each came exquisitely presented and served with some spectacular new trick, from a hot pot broth into which you dipped slices of wild boar to a mini charcoal grill for barbecuing mountain trout and an ice platter for serving a fan of delicate sashimi. Even what sounded as ordinary as a turnip sushi roll turned out to come wrapped in a tiara-like crown of bark.

I'm not sure the Japanese have a phrase to describe locating your 15th stomach but I had no trouble finding it, when the most refined dessert I've ever seen - a Japanese pear and cava jelly scattered with pomegranate seeds - was slipped quietly in front of me.


Staying at Koya-san starts at around Y9,500 (pounds 49) per person per night, including dinner, bed and breakfast. For more information see www.shukubo.jp. To book call 00 81 736 56 2616, or visit www.sekaiisan-wakayama.jp/ visitkoyakumano.

If you'd rather go as part of an organised tour, contact the Japan National Tourist Organization (020-7734 9638) or see www.seejapan.co.uk.

Double rooms at Sumiya-Kihouan, including dinner and breakfast, start at Y24,000 (pounds 123) (00 81 771 22 0394; www.sumiya.ne.jp).