Sumi-e is the Japanese art of ink-wash painting: graded black sumi diluted into tonal grays (notan), dry-brush strokes that leave "flying white" (kasure), and the vast emptiness of unpainted paper (ma). Nothing is added that the brush did not need. The ground is aged mulberry washi — a toned, weathered oatmeal — and the single point of color is the red of a carved seal pressed in cinnabar paste. This is a system built on restraint: most of the surface stays empty, and one small vermilion mark carries the whole composition.