Determination of the day of the week in the year row (07) is located in column G. The letter in the century row (13) and column G is E, so the day of the week is Friday. January 1 corresponds to G, G in the year row (00) corresponds to F in the century row (20), and F corresponds to Saturday. A pithy formula for the method: ""Date letter (G), letter (G) is in year row (00) for the letter (F) in century row (20), and for the day, the letter (F) become weekday (Saturday)"". Use 17 (in the Gregorian century row, column C) and 83 (in
Eight-day week a day. Further, they also counted the ending night period, giving rise to periods of time with more nights than days. In Irish, the term "nómad" is used to signify a small number of days and is exactly the length of the nine night week as in "co cend nomaide" - a period of time with nine nights bracketing eight days. The nine nights divided nicely into a sidereal month of 27 nights. In Welsh a similar word "wythnos" meaning "a week" literally means "an eight-night" since it started and ended with a period of night bracketing seven days. Similarly