Cursive script (caoshu, 草書), sometimes known as “grass” script, developed around the end of the Han dynasty (AD 220). Although the basic elements of cursive script matured in the third and fourth centuries, important innovations continued until the middle of the Tang dynasty (618–907). In cursive script, individual strokes within a character are drastically simplified and abbreviated, often becoming a single continuous movement of the writer’s brush. Since the number and structure of strokes significantly changed, both the ability to read and write cursive script requires special training and study.