Kuksadang, the shamans' national shrine, a wizened spirit tree and a nearby spring known as the Water Dragon's Palace set on the western ridges of this 385-metre-high forested mountain are sacred to Korea's shamans. But Kuksadang, on Inwhang's mid-level slopes, is equally important to Buddhists. It shares its location with a traditional village of small temples and homes in the shadow of a surreal geographical formation known as the Zen Rocks - so called because they resemble robed monks at prayer.

But all is not well on Mt Inwhang. A giant excavation of raw earth just below Kuksadang marks the site of a huge apartment complex, threatening the mountain's spiritual energies. Shamanistic practices are also under attack from the Buddhist community.

Shamans - like the witches of Europe - are almost all female. A strange remnant of the past in hi-tech Korea, their rituals and mnemonic poems predate written records. Many Koreans see them as a primitive anachronism.

'My family members strongly opposed me becoming a shaman,' said Seol, a teacher before her initiation seven years ago. 'Even now, her mother and brother are the only family members that know I am a shaman.'

Not everyone can join this exclusive sisterhood. 'My grandmother was a shaman; she died when she was 35,' said Seol, whose gift skipped a generation, as her mother refused initiation.

Like most shamans, the younger Seol suffered from an inexplicable run of ill luck and sickness before an older shaman arrived to inform her of her calling and initiate her in a 'spirit acceptance' ceremony. Once she accepted that she was a shaman - and accepted her personal spirit - her problems evaporated. Now, the spirits speak through her. 'Some shamans see images or hallucinations; others hear voices in their heads,' she said. 'In my case, I just speak spontaneously.' But it took her a while to control her gift. On occasions, a child's spirit has entered her while she's shopping in department stores, prompting her husband to buy her toys.

With a regular clientele of 50 people, Seol, makes the bulk of her living from fortune telling and performing good luck rituals. The most specialised of her skills - performing exorcisms - is more demanding.

'I have to refrain from eating certain foods and abstain from sex before an exorcism - this is why so many shamans get divorced,' she said. 'And I can suffer side effects: for example, if I exorcise a spirit that died of stomach cancer, I get stomach pains, but these minor demons usually go away after a few days.'

While kuts are a fairly common sight, exorcisms are usually performed privately.

'She was moving like a marionette without strings,' said Stephen Rooney, a Canadian religious scholar, of a shaman he witnessed performing the ritual.

Because of the spirits who are believed to posses and accompany them, shamans are not permitted to attend funerals. There are upsides, though: Seol says that in spring and summer, butterflies follow her.

But it is not just spirits that shamans bring to Inwhang. Scattered around the slopes are burnt out candles, strips of coloured muslin and empty bottles of rice beer and grain spirit - all common elements in rituals. The shamans' penchant for noise and libation irritates their more ascetic Buddhist neighbours: near the Zen Rocks is a sign forbidding shamanistic rituals in the vicinity.

'They bang gongs, especially on summer nights, scatter litter, leave candles and so on,' said Bo Deok-haeng, the wife of the head monk of the Mt Inwhang Seonan Cheongsa Buddhist Temple. 'They could be respected as a traditional religion, but they create a bad image.'

The animosity is mutual. 'These days, some monks are incorporating shamanism - they study fortune telling, for example,' said Hwang Kyong-yol, Seol's husband. 'I think the Buddhists are losing their believers, so they are doing these things to win converts.'

However, one thing both groups are united on is their criticism of the giant apartment development springing up at the foot of Mt Inwhang. 'This development hurts the area's qi badly,' said Seol. 'It is hurting the mountain.'

With the mountain always having been strategically vital, the developers face height restrictions. To the south of Mt Inwhang is Gyeongbokgung, the erstwhile royal palace; the presidential Blue House is today set behind this auspicious location, and protective army positions can be seen behind the medieval city walls that crawl over Inwhang's summit ridges.

These military requirements mean that Kuksadang's spectacular views will not be impeded by the development.

Even so, residents are concerned. 'This mountain is a living thing - full of qi,' said the Venerable Son Hye-won, a local Buddhist monk. 'If you compare the mountain to a body, it is like cutting off the legs.'

And in an implicit warning that it may be risky for property developers to tempt fate, Seol said: 'They should be careful. There could be some kind of accident before they complete construction.'