Akan calendar

The Akan people (a Kwa group of West Africa) appear to have used a traditional system of timekeeping based on a six-day week (known as nnanson "seven-days" via inclusive counting). The Gregorian seven-day week is known as nnawɔtwe (eight-days). The combination of these two system resulted in periods of 40 days, known as adaduanan (meaning "forty days").