Tosa-shikkui

What tosa-shikkui means

Tosa-shikkui is the lime plaster traditionally used in Kochi Prefecture, the former province of Tosa, to finish outer walls and eaves. Ordinary lime plaster is mixed with a glue boiled from seaweed to make it easier to spread; Tosa plaster is said to use no glue but instead to include fermented straw fibre and to be built up in thick coats. Without the glue it is less easily washed out by rain, which is the usual explanation for its use in a region exposed to frequent typhoons. It goes on white and is said to take on a faint yellow tint over the years.

Walls of Tosa plaster are often paired with devices that shed rain. In Kiragawa, in the city of Muroto, the seaside district is lined with townhouses plastered all over in the Nuriya-zukuri manner, their walls fitted partway up with several horizontal rows of small tiles. These drip tiles, mizukiri-gawara, throw off water running down the wall before it can soak the plaster, and the combination of Tosa plaster and drip tiles is a hallmark of Kochi townscapes.

Reading the records and the building

Records specify which parts of a wall are finished in Tosa plaster. The gatehouse of the Morisawa family has a lower wall of weatherboarding with battens and an upper wall of Tosa plaster, and the family's barn is described with Tosa plaster on the upper part of an exposed-post wall. At the Goto family house in Aki, the gable and the upper south face of the barn and the small wall panels of the office are finished with it. Boarding the lower wall to protect the vulnerable base and plastering above is evidently a common arrangement.

Some buildings in Kochi are recorded simply as plastered, without the word Tosa. Articles should follow the record and not add the regional name just because a building stands in the prefecture.

On site, look at the smoothness and thickness of the wall, whether the plaster continues up under the eaves, and whether there are drip tiles. A yellowish tone is said to indicate Tosa plaster, but dirt and later recoating also change the colour, so appearance alone cannot settle the material.