After consulting his advisers, Kublai decided to cement his claim by casting the I Ching, an ancient Chinese system of divination with links to both Confucianism and Taoism. To face down the threat from Arigböge he chose an impressive ritual that would give him unshakable legitimacy.
Kublai knew that whoever succeeded Möngke would need formidable diplomatic as well as military skills to hold together a colossal patchwork of lands that stretched from northern China through Persia to Russia. (Out of Eden: National Geographic Explorer Paul Salopek reports from Xanadu.) Kublai, then age 45, hastily made his way to his residence at Shangdu (later immortalized as Xanadu in Samuel Taylor Coleridge’s famous poem “Kubla Khan”) to decide what to do next. News reached Kublai that another of his brothers, Arigböge, also wanted to proclaim himself emperor.