Wang Anshi, courtesy name Jiefu (介甫), art name Banshan (半山), was a Chinese politician, poet, philosopher, and economist during the Song dynasty. He served as chancellor and attempted major and controversial socioeconomic reforms known as the New Policies. These reforms constituted the core concepts of the Song-dynasty Reformists, in contrast to their rivals, the Conservatives, led by the Chancellor Sima Guang.