Overview
Each term in the sexagenary cycle consists of two Chinese characters, the first representing a term from a cycle of ten known as the Heavenly Stems (天干; tiāngān) and the second from a cycle of twelve known as the Earthly Branches (地支; dìzhī). The first term (甲子 jiǎ-zǐ) combines the first heavenly stem (甲; jiǎ) with the first earthly branch (子; zǐ). The second (乙丑; yǐ-chǒu) combines the second stem with the second branch. This continues, generating a total of 60 different terms (the least common multiple of ten and twelve), after which the cycle repeats itself. This combination of two sub-cycles to generate a larger cycle and its use to record time have parallels in other calendrical systems, notably the Akan calendar.
Read more about this topic: Sexagenary Cycle