Liushu (The Six Methods) refers to a system which describes how Chinese characters are constructed using six methods. First coined in The Rites of Zhou, these methods were further studied and summarised by the Eastern Han writer Xu Shen as follows: xiangxing (pictograph), zhishi (simple ideograph), huiyi (compound ideograph), xingsheng (phonetic-semantic compound), zhuanzhu (transfer character) and jiajie (loan character). The Six Methods help us understand the nature and evolution of Chinese characters, as they explain the formation of each character as well as its components.