Gassho-zukuri

Gassho-zukuri is a style of Japanese farmhouse with a very steep, thatched gable roof, found mainly in the mountain villages of Shirakawa-go (Gifu Prefecture) and Gokayama (Toyama Prefecture). The name is usually translated as "prayer-hands construction", because the two roof slopes meet at the top like palms pressed together. The Historic Villages of Shirakawa-go and Gokayama were inscribed as a UNESCO World Heritage site in 1995.

The style is a form of kayabuki, the general Japanese term for grass-thatched roofs, and represents one of its most dramatic regional versions.

Designed for snow

The villages sit in valleys that receive very heavy snowfall. The steep roof pitch lets snow slide off rather than build up, and the heavy timber structure is built to carry what does remain. In some villages, forests on the slopes above are protected because they help hold back snow from the houses.

Use of the roof space

The tall roof creates several attic levels. Historically these upper floors were used mainly for raising silkworms, which needed room for trays of larvae and for storing mulberry leaves. Space beneath the ground floor was used to produce nitre, an ingredient of gunpowder. The roof was therefore both shelter and workplace.

Rethatching and community labour

A gassho-zukuri roof was traditionally rethatched about every 30 to 40 years. The work relies on yui, a system of unpaid mutual labour among households. Preparations begin years in advance, and a re-roofing day can involve 200 to 300 people. Men work on the roof while others prepare food, and one side of a roof is typically finished in about two days. Today volunteers and heritage organisations support the villages with this work.

Surviving houses

Around the time of inscription, Ogimachi in Shirakawa-go had 59 gassho-style farmhouses, Ainokura in Gokayama had 23, and Suganuma had 9. Fire is the main threat to thatch, so all three village areas have elaborate fire-extinguishing systems and organised resident fire-fighting squads.

Place in Japanese roofing

Gassho-zukuri contrasts with the clay kawara tile roofs common in Japanese towns. It shows how rural builders used locally harvested grasses and timber to deal with a severe snow climate.