Hiwadabuki

What hiwadabuki means

Hiwadabuki is a roof built up from thin sheets of cypress bark, laid in shallow overlaps and pinned with bamboo nails. Because the material is thin and pliable it follows curved surfaces far more readily than tile or board.

The National Cultural Properties Database records it as the covering, after the shape of the roof. The main hall of Hazu Shrine in Aichi Prefecture is entered as a single-bay shrine, Irimoya-zukuri, Tsumairi, with a front canopy and a cypress-bark roof; the main hall of Takasu Shrine in Fukuoka Prefecture as a three-bay Nagare-zukuri hall with the same covering. Shape and material vary independently.

Temples use it as well. One building at Kongobuji in Wakayama Prefecture is recorded as three bays by three, single-tiered, with a pyramidal roof, a one-bay front canopy and a cypress-bark covering. A pyramidal roof also carries curvature, which suits the material.

Scale is no barrier. The Nakanobo Inari shrine in Nara Prefecture is recorded as a single-storey timber hall of 1.4 square metres, roofed in cypress bark.

Telling it from a tiled roof

Look at the eaves from the side. A cypress-bark roof shows a stack of thin layers cut to a clean line, and the surface runs as one smooth curve with none of the repeating ridges that tiles produce.

Colour is a poor guide. Newly laid bark is a warm brown that darkens towards near-black over the years, so photographs taken at different times can suggest different materials on the same building.

The covering is meant to be replaced at intervals. Records sometimes note a temporary sheet-metal covering over the permanent material, which means the roof is protected while the proper covering is prepared. What a building carries today is not necessarily what it carried when built.