Chajian 茶箋 is a book on tea written during the late Ming period 明 (1368-1644) by Wen Long 聞龍 (1551–1631), courtesy name Yinlin 隱鱗 or Zhonglian 仲連, style Feidun Weng 飛遁翁, from Siming 四明, i.e., Ningbo 寧波, Zhejiang.
The text is found in the series Xu shuofu 續說郛, Jujia bibei 居家必備 and Meishu congshu 美術叢書, and is quoted in the encyclopaedia Gujin tushu jicheng 古今圖書集成, but both versions are seemingly not complete. The book is mentioned in Master Xu's 徐氏 Mingtan 茗譚 from 1613.
The Chajian consists of 10 paragraphs describing the plucking and processing of tea leaves, the qualities of water from Siming and various tools for preparing and serving the beverage.