It is called Suihi (水干) , as it is made by purifying with water (水(sui))and drying up(干(hi)). It is a tinted pigment with high light-stability, using gofun(shell powder) as an extender. It is often utilized as an under coating since it enables to paint evenly at less cost, compared to natural mineral pigments. By over-painting, it allows to express more complex colors and produce richer colors.