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 collectanea 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.