According to R. C. Bell, the earliest known board for the game includes diagonal lines and was "cut into the roofing slabs of the temple at Kurna in Egypt"; he estimated a date for them of  BCE. However, Friedrich Berger wrote that some of the diagrams at Kurna include Coptic crosses, making it "doubtful" that the diagrams date to 1400 BCE. Berger concluded, "certainly they cannot be dated." When played on this board, the game is called "tapatan" in the Philippines and "luk tsut k'i" ('six man chess') in China. It is thought that "luk tsut k'i" was played during the time of Confucius, c. 500 BCE. Centuries later, the game was mentioned in Ovid's "Ars Amatoria", according to R. C. Bell. In book III (c. 8 CE), after discussing , a popular board game, Ovid wrote: