From the beginnings of Chinese literacy in the late 2nd millennium BCE, Chinese time-keeping has employed two sets of cyclical terms among its notational apparatus. One set consists of ten terms, and is referred to here as the 10-cycle (table 1). The second has twelve, and is referred to here as the 12-cycle (table 2). A cycle of sixty terms (here, the 60-cycle, but commonly referred to as the sexagenary or sexagesimal cycle) combines terms from the 10- and 12-cycles in pairs. Beginning with the pair jiǎzǐ 甲子 (the first terms in the 10- and 12-cycles) and repeatedly incrementing …