Western Han Dynasty artifact, a silk manuscript. Unearthed in 1973 from the No. 3 Han Tomb at Mawangdui in Changsha, Hunan, it is the oldest meridian study work discovered in China to date. Copied on a long scroll approximately 24 cm wide and 450 cm long, the first 1/6 of the silk manuscript contains four texts: Zubi Shiyimai Jiujing, Yinyang Shiyimai Jiujing (Version A), "Mai Fa," and "Yin-Yang Mai Si Hou." The remaining 5/6 of the scroll is occupied by Wushi'er Bingfang.