In 1086, Cai Jing was posted to the administrative office in Kaifeng, the capital. He supported the conservative faction in the imperial court, headed by Sima Guang, and won the praise of Sima. In 1094, Cai Jing became the Minister for Revenue. He helped Zhang Dun () revive the New Policies of reformist chancellor Wang Anshi, although he set out on a campaign of attrition to destroy or radically alter the written work of his predecessors and especially conservative enemies, thereby probably also purging much of Shen Kuo's written work.