Calligraphy/sumi-e hair: goat hair (most common, soft, high ink capacity), weasel/kolinsky (called itachi or ten, firm with excellent point retention), tanuki — raccoon dog hair (stiff, holds a straight, well-gathered tip, favoured for menso-fude fine-detail brushes and kegaki-fude line-drawing brushes) Colour-coded hair convention: white-toned brush heads generally signal goat hair (soft, suited to flowing script); brown-toned heads signal horse, tanuki, weasel, or deer (firmer, more elastic) Rare and vanishing material: brushes once made from a specific rat found along Lake Biwa's shoreline are now nearly unobtainable — decades of shoreline construction destroyed the habitat, and the material simply disappeared within a generation Ceremonial brush: uike-fude (胎毛筆), made from a baby's first haircut — kept as a birth memento, generally understood in Japan to have arrived from Chinese custom rather than as a native Japanese practice Unexpected modern extension: Kumano's calligraphy and painting brush expertise became the foundation of Japan's globally respected cosmetic brush industry — the same hand-selection and tapering skill used for ink brushes is now applied to makeup brushes exported worldwide