Names of the days of the week is followed by a number indicating the day: "Monday" is literally "star day one", "Tuesday" is "star day two", etc. The exception is Sunday, where rì (日), meaning "sun" or "day", is used instead of a number. In Swahili, the day begins at sunrise, unlike in the Arabic and Hebrew calendars where the day starts at sunset (therefore an offset of twelve hours), and unlike in the Western world where the day starts at midnight (therefore an offset of six hours). Saturday is therefore the first day of the week, as it is the day that includes the first night
Determination of the day of the week for the following month. The item for January is "0"; for February or March, "3"; for December, "12". Day-item: The total, thus reached, must be corrected, by deducting "1" (first adding 7, if the total be "0"), if the date be January or February in a leap year, remembering that every year, divisible by 4, is a Leap Year, excepting only the century-years, in `New Style', when the number of centuries is not so divisible (e.g. 1800). The final result gives the day of the week, "0" meaning Sunday, "1" Monday, and so on. Examples: 17, divided by 4, leaves