A commentary to the Shiji cites a now-lost book as quoting Shen Buhai saying: "By employing (yin), 'passive mindfulness', in overseeing and keeping account of his vassals, accountability is deeply engraved." The Guanzi similarly says: "Yin is the way of non-action. Yin is neither to add to nor to detract from anything. To give something a name strictly on the basis of its form – this is the Method of yin." Yin also aimed at concealing the ruler's intentions, likes and opinions.