Libian (simplified Chinese: 隶变; traditional Chinese: 隸變; pinyin: lìbiàn; lit. 'clerical change') refers to the natural, gradual, and systematic simplification of Chinese characters over time during the 2nd Century BC, as Chinese writing transitioned from seal script character forms to clerical script characters during the early Han dynasty period, through the process of making omissions, additions, or transmutations of the graphical form of a character to make it easier to write. Libian was one of two conversion processes towards the new clerical script character forms, with the other being (Chinese: 隸定), which involved the regularisation and linearisation of character shapes.