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 (774-836). It was commented by Yuan Ge 元革, a contemporarian. The book describes a board game called chupu 樗蒲 and added (in the original version) several drawings to explain individual moves. 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).