Despite the critical advances toward khipu decipherment, the specific ways in which Andean khipu masters captured and organized the course of time in their cords, in the form of ages, dates, chronologies, and calendric intervals and cycles, remains obscure. This essay contributes to this central problem of knot making and reading traditions by enlisting the aid of an unlikely source: the memoirs of a mid-nineteenth-century gentleman who was given a striking account of how khipu masters in Cuzco’s countryside recorded specific events of a twelve-month calendar in their khipus and made accurate calculations based on them. The analysis and reconstruction of Cuzco’s calendar-demographic khipus is framed into the history of Catholic catechesis, which included early efforts at colonizing indigenous ways of thinking and experiencing time through tactile, visual, and sonic strategies. This process, rather than marginalizing knotted cords all together, as it is sometimes assumed, turned khipukamayuq into important, yet often overlooked agents for the gradual establishment of the Roman Catholic calendar in Andean rural parishes. Unraveling the basic principles for the accounting of time in these modern khipus by placing them in their historical context is a firm, and to our knowledge unprecedented, step toward future efforts at deciphering both quantitative and qualitative cords with a temporal component.