Ink brush

Ink brushes (Traditional Chinese: 毛筆; Simplified Chinese: 毛笔; Pinyin: máo bǐ, in Japanese fude) are used in Chinese calligraphy. They are also used in Chinese painting and descendant brush painting styles (such as sumi-e).

Brushes differ greatly in terms of size, texture, material and cost.

Size: Generally classified as either big (大楷), medium (中楷) or small (小楷); most calligraphy is written with a medium-sized brush. The smallest brushes are used for very small pieces and to sign works. Medium brushes are the most widely used; wielded by a skilled artist, a medium brush can produce a variety of thicknesses of line, from very thin to fairly thick. The largest brushes are used only for very large pieces.
Texture: Either soft (軟毫), hard (硬毫) or mixed (兼毫). Certain textures are better for writing certain styles than others are.
Material: Normally the brush is made from sheep, pig, mouse, buffalo, wolf and rabbit hair, while exotic ones can be made from tiger, fowls, deer, yellow weasel (黄鼠狼) and even human baby hair (from the first haircut a baby gets, said to bring good fortune while taking the Imperial examinations).
Stalk material: Usually normal bamboo, exotic brushes instead may use materials like gold, silver, jade, ivory, red sandalwood or mottled bamboo.
The material one chooses to use depends on one's needs at the moment, certain kinds of brushes are more suited to certain script styles and individuals than others are. Synthetic hair is not used. Prices vary greatly depending on the quality of the brush, cheap brushes cost less than a US dollar while expensive can cost more than a thousand. Currently, the finest brushes are made in Huzhou in Zhejiang.

Together with the ink stone, ink(stick) and paper, the four writing implements form the Four Treasures of the Study.