The manor of using a painting brush in Eastern art and calligraphy. Brush use technique was first mentioned by Xie He (Jp: Sha Kaku 謝赫, late 5th century) in his Six Principles of painting appreciation *rikuhō 六法. The second principle, the bone manner koppō yōhitsu 骨法用筆 refers primarily to linear drawing. Jing Hao (Jp; Kei Kō 荊浩) of the Liang dynasty in the Five dynasties period wrote the Hippōki 筆法記, which expounds on the Six Principles. He further described the bone manner as embodying four forces: sinew or muscle suji 筋, flesh or meat niku 肉, bone hone 骨, and spirit ki 気, which served to define the basic qualities of brushwork in ink painting which developed during the Five dynasties and Song periods. Another term, unpitsu 運筆 is used in much the same way to refer to the way the brush is used. The line which is produced depends on various factors such as the way the brush is held and moved, the speed of the stroke and the width of the brush.