Kokerabuki

Kokerabuki (柿葺, also 杮葺) is a traditional Japanese roof covering of very thin wooden shingles. The shingles, called kokera, are split rather than sawn, and are laid in many closely spaced courses to form a light, finely textured roof. It is used on temple halls, pagodas and pavilions, and is one of the techniques used to roof Kyoto's Golden and Silver Pavilions.

Material and size

Kokera are traditionally split from Japanese cypress (hinoki), though other woods such as cedar are sometimes used. A typical shingle is about 3-5 mm (0.1-0.2 in) thick, 9-15 cm (3.5-6 in) wide and about 30 cm (12 in) long. They are fixed with bamboo nails.

Technique

The shingles are laid in tight, overlapping courses so that only a small part of each is exposed, building up a roof several layers thick. The thinness of the shingles allows them to follow curved roof surfaces and sweeping eaves.

Relationship to other wooden roofs

Japanese builders used a family of wooden roof coverings. Thin shingles were common on houses in medieval Kyoto, where they were often held down with stones. Hiwadabuki, layered cypress bark, uses a similar nailing method but a different material. Where thatch was hard to obtain, minka builders also used shingles instead.

Heritage

Wooden-shingle roofing, together with cypress-bark roofing, is among the 17 traditional skills inscribed by UNESCO in 2020 as "Traditional skills, techniques and knowledge for the conservation and transmission of wooden architecture in Japan". The production of wooden roofing materials is listed as a separate skill.

Examples

• Kinkaku-ji and Ginkaku-ji, Kyoto - very thin split-wood shingles fixed with bamboo nails.
• Anraku-ji octagonal three-storey pagoda, Nagano - used by the JAANUS dictionary to illustrate the entry.