Polished Tosa Shikkui

By Kyle Holzhueter

Tosa Shikkui is a traditional lime and straw fiber plaster from Kochi Prefecture. Located on the south coast of Shikkoku and facing the Pacific Ocean, Kochi Prefecture is known to be prone to typhoons. Tosa Shikkui is a weather resistant lime plaster used for generations in this harsh climate. It’s produced by fermenting a mix of slaked lime and straw fibers.

The following photos describe the process of polished Tosa Shikkui:

Materials

First, loosen the mix and break up clumps by stepping on bags.

Continue mixing in a mortar mixer or in a barrel with a hand mixer. After the Tosa Shikkui has been loosened in the mortar mixer, remove enough cream “Noro” to polish the desired area; approximately 1.5 liters per 2 m².

In order to produce the cream “Noro” that is used for polishing, Tosa Shikkui is strained through a 1.5mm sieve. For a finer polish, the cream noro can be further sieved through a 80+ mesh. To make sifting easier, the Tosa Shikkui can be mixed with a slight addition of water.

Tosa Shikkui filtered cream “Noro”

Color pigments can be added.

One part cream mixed with 3-4 parts “Shoen”, a black pigment made from pine ash.

30% red iron oxide mixed with noro to create a red plaster.

Mixed with a hand mixer.

Mixing the cream and pigment in a bag is also clean and convenient.

Application

Apply first coat of Tosa Shikkui over an earth plaster brown coat. Depending on the area to be polished and the need to reduce suction, the brown coat can be dampened and/or a layer of Tosa Shikkui and sand can be applied.

Apply second coat of Tosa Shikkui

Compress. Any variations in the surface of the Tosa Shikkui will be reflected in the finish coat.

Tosa Shikkui Finish without Noro.

When the Tosa Shikkui has stiffened up and begins sucking moisture again, the finish coat of cream Noro is applied with a Jigane trowel.

Even with a Jigane trowel, horizontal and then vertical. Remove excess cream Noro. When the variations have been corrected…

Compress with polished Jigane. The Jigane must be polished or it will scratch the surface.

When there is too much friction to compress with the Jigane, apply Unmo (mica group of aluminosilicates) or Tonoko (powdered stone local to Kyoto), which functions like baby powder, bringing moisture to the surface.

The powder is wrapped in clean cloth and applied to the wall.

Rubbing with your hand or soft cloth, cover the surface evenly. Before continuing, remove any access with one’s hand and a soft cloth.

Continue compression with a Jigane. After application of the baby powder, one should be able to compress with the Jigane without too much friction. Continue compressing horizontally.

When there is too much friction for the Jigane, use a polished Honyaki Finishing Trowel for Compression. Should be polished with 1000-2000 grit water resistant sand paper.

And when there is too much fiction for the finishing trowel, continue compression with a polishing trowel.

Yamanishi-san’s Ultimate Honyaki Finishing Trowel

And when there is too much friction for the polishing trowel, continue polishing with one’s hand.

It’s recommended that the night before, one wash one’s hands thoroughly, apply hand cream and sleep wearing soft cotton gloves.  By doing so, one’s hands are incredibly soft and will not scratch the surface.

The most common technique is to pull one’s thumb to continue horizontal movement while pressing against the wall.

Another technique is to pull the wrist.

Further hand polishing with a cotton glove and soft buffing cloth.  Nearing completion…

Polished Tosa Shikku