The Cantong qi is deemed to be the earliest book on alchemy in China. The title has been variously translated as Kinship of the Three, Akinness of the Three, Triplex Unity, The Seal of the Unity of the Three, and in several other ways. The full title of the text is Zhouyi cantong qi, which can be translated as, for example, The Kinship of the Three, in Accordance with the Book of Changes.