Gofun

Many types of pigments were once brought to Japan from China, and the pigment known as gofun in Japan originally denoted white-lead pigment. However, due to the humid environment of Japan, white lead would turn black, thus making it difficult for this pigment to remain white. Over the centuries, oyster shells gradually replaced white lead as the raw material for making white pigment. Today, gofun continues to be used as white pigment in traditional art and craft. 

Ostrea denselamellosa (Densely lamellated oyster) is a species of oyster whose shells are used to create gofun. The shells are first given 10 to 15 years of natural drying against the elements, a process that breaks down organic substances contained in the shells and allows foreign objects such as stone or fish scales attached to the shells to be easily removed. Gofun made from oyster shells is an excellent pigment that is resistant to flaking and soft enough to be easily applied with a brush and guarantees long-lasting whiteness. 

First, gofun powder is placed inside a mortar and crushed with a pestle.  

The process of gofun-making involves first placing air-dried shells into a machine called kaikuruma, where they are thrown against each other to remove foreign objects attached to the surface of the shells.   

The small shell pieces are further crushed to a finer form. 

The shell powder is ground to an even finer form as desired. 

After removing impurities, the fine gofun is spread evenly over a board made from Japanese cedar and allowed to dry naturally over a period of about 10 days. Once dry, the powder is removed by tapping on the back of the board. This completes the making of gorun powder, a process that takes about 2 months from the initial kaikuruma shell cleaning.