Tokushima prefecture is Japan's biggest domestic producer of indigo plants. Unlike painted wood, Dairi Lumber Co., Ltd. products exhibit a rich blue that allows natural wood grains to show using natural ingredients. The coasters are made with Tokushima cedar completed with a natural oil paint coating to prevent indigo from staining other surfaces.
Dairi Lumber offers interior and building materials, including logs, as residential building materials. The company has the largest market share in the Shikoku area in the manufacture of two-by-for-home houses paneling. Recently Dairi Lumber established an indigo coated materials technology that can be used as a paint or spray and applied it to designs that make use of wood as part of construction materials, interiors, or small objects.