What is "zuowanglun"

The Zuowanglun or Zuowang lun is a Daoist meditation text that was written by the Shangqing School patriarch Sima Chengzhen (647–735). Daoism incorporated many Buddhist practices during the Tang Dynasty (618–907), and the Zuowanglun combined meditation techniques from Daoism (e.g., zuowang "sitting forgetting" and guan 觀 "observation") and Buddhism ( samatha "calm abiding" and vipassanā "insight").