A purple dye senryō 染料 made from the roots of the perennial plant Gromwell (Lithospermum erythrorhizon) *murasaki 紫, which grew in Japan, the Korean peninsula and north-eastern China. The plants were picked, the roots soaked in cold water, crushed in a mortar, and then rubbed in hot water to make the dye. Woodlye was used as a mordant baisenzai 媒染剤; a variety of purple hues were obtained depending on the quantity and type of wood lye used. The murasaki plant was difficult to cultivate, and so dye-makers depended on the collection of scarce wild plants. The quantity of coloring matter contained in the roots was also small, so in the Edo period, sappanwood *suō 蘇芳, was used to obtain a purple dye known as nise-murasaki 偽紫 (false purple), in contrast to the original dye hon-murasaki 本紫 (true purple). An old name used to refer to purple dyes and pigments was *shido 紫土.