Sumi brushes are unlike watercolor, oil and most other paintbrushes as they are composed of two separate parts. The central core, which determines the height and basic function of the brush, is made of relatively stiff hairs gathered to form a tapered point, while the outer wrapping consists of softer hairs which are selected for their greater water-holding capacity and for facilitating smooth strokes. They feature a combination of horse, badger, deer, and sheep hair of the same length that come to a point when dipped into water. The hair structure ensures smooth maneuverability and dynamic strokes whether light or heavy pressure is applied.