Zenkoji

Zenkoji was founded in the seventh century, before Buddhism in Japan divided into schools, and it belongs to none of them - it is run jointly by a Tendai and a Jodo institution, and it has always admitted women on equal terms, which was not the case at many mountain temples. That openness made it one of the great pilgrimage destinations. The main hall of 1707 is a national treasure and among the largest wooden buildings in the country. Under it runs the kaidan meguri: an unlit passage in complete darkness where you feel along the right-hand wall for a metal key said to hang below the hidden image, touching it being understood as a promise of salvation. The darkness is total and the walk takes a couple of minutes. The temple's principal image has not been shown publicly for centuries; a copy is displayed every six years.

What you actually see

• The 1707 main hall - a national treasure and one of Japan's largest wooden buildings.
• The dark passage - an unlit corridor where you feel for a key on the wall.
• A non-sectarian temple - older than the schools, run jointly, open to women throughout.
• A hidden image - never shown publicly; a copy displayed once every six years.

When to go

All year; the morning service at dawn is the local recommendation. Two to three hours.

Honest expectations

The dark passage is genuinely pitch black and unsuitable for anyone claustrophobic. The inner sanctuary and passage are charged. Nagano winters are cold and snowy. The six-yearly showing brings enormous crowds.

Nearby

Nagano station and the approach street are south; Togakushi is north-west.