What urushi is
Urushi is the refined sap of the lacquer tree. Applied in coats and allowed to harden, it forms a durable film that protects the timber beneath and gives a deep gloss.
Interiors are finished with it. Eishoji in Kanagawa Prefecture, founded in 1643, is recorded as an Important Cultural Property whose memorial hall, three bays square under a Hōgyō-zukuri roof, is decorated inside and out in lacquer and colour.
Whole buildings sometimes carry it. The Konjikido at Chusonji in Iwate Prefecture, completed in 1124 and recorded as a National Treasure, is described as lacquered black and covered in Kinpaku inside and out, from the veranda to the eaves. The lacquer also serves as the ground for the leaf.
Sculpture works the same way. The seated Dainichi Nyorai in a shrine cabinet at Kotokuji in Tokyo, a Kamakura-period work, is described as finished in lacquer and gold.
Not to be confused with lime plaster
The Japanese word for lime plaster contains the same first character, but Shikkui is a different material: slaked lime for walls, not tree sap for timber. A record naming one means the wall finish, the other the coating on woodwork.
Searching runs into the same trap. A search on the bare character returns mostly plaster, so the term needs narrowing to lacquering, black lacquer or lacquer-and-leaf.
Several craft techniques build on it. The Konjikido description notes mother-of-pearl arabesques over sprinkled gold on the columns, Nageshi and Kumimono of the Naijin, with bodhisattvas painted in gold lacquer on the columns.
On site, judge by the surface. A deep black gloss with bare wood showing where it has flaked is lacquer; a hard white surface is plaster.
References
- Agency for Cultural Affairs: National Treasures and Important Cultural Properties (structures)
- https://www.bunka.go.jp/seisaku/bunkazai/shokai/yukei_kenzobutsu/kokuho_bunkazai.html
- National Cultural Properties Database: Eishoji, whose memorial hall is three bays square under a pyramidal roof
- https://kunishitei.bunka.go.jp/bsys/maindetails/102/00004634
- Cultural Heritage Online: Chusonji Konjikido, lacquered black and gilded inside and out from veranda to eaves
- https://online.bunka.go.jp/db/heritages/detail/199039
- Cultural Heritage Online: seated Dainichi Nyorai in a shrine cabinet at Kotokuji, lacquered and gilded with a wooden halo
- https://bunka.nii.ac.jp/heritages/detail/202433
Last verified: 2026.09.10