The Wumujing 五木經 "Classic of the five wooden pieces" is a very short book on gaming authorship of which is attributed to the Tang period 唐 (618-907) writer Li Ao 李翱. It was commented by his contemporarian Yuan Ge 元革. It describes a board game called shupu 樗蒲 and originally explained the game with the help of drawings. The pieces were called zi 子, ma 馬 and wumu 五木. The rules of the game said that if a gamer obtained six "horses" and tossed the "five wooden" pieces (wumu) he could obtain one of ten lots (cai 采), of which lu 盧, zhi 雉, du 犢 and bai 白 were the most precious. Such a lot allowed him to toss one more and to "strike a horse" (dama 打馬) or to "enter the pass" (guoguan 過關).
The Wumujing is included in the reprint series Jindai mishu 津逮秘書, Tangren shuohui 唐人說薈, Tangdai congshu 唐代叢書 and Congshu jicheng 叢書集成.
Source: Wu Feng 吳楓 (ed. 1987). Jianming Zhongguo guji cidian 簡明中國古籍辭典, p. 96. Changchun: Jilin wenshi chubanshe.