Editing Soviet calendar (section)

== Six-day weeks ==
[[File:Soviet calendar 1933 color.jpg|thumb|left|Soviet calendar, 1933 <br/> Days grouped into 7-day weeks (still starting with Sunday). Rest day of six-day work week in blue. Five national holidays in red]] 
[[File:Soviet kalendar 1939.jpg|thumb|upright|Soviet calendar, 1939 <br/> Reusable every (common) year: Six-day work weeks only, days denoted "First" to "Sixth". Each 31st is extra, February is short. ''Six'' holidays in red and listed below – added 5 December for [[Stalin Constitution]] of 1936; special box for [[21 January]] remembrance]]

From the summer of 1931 until Wednesday {{nowrap|26 June 1940}}, each ''Gregorian month'' was divided into five six-day weeks, more or less (as shown by the 1933 and 1939 calendars here).<ref name=Foss/> The sixth day of each week, that is days 6, 12, 18, 24, and 30 of the month, was a uniform day off for all workers. The last day of 31-day months was always an extra work day in factories, which combined with the first five days of the following month made six successive work days. But some commercial and government offices treated the 31st day as an extra day off. To make up for the short fifth week of February, which had just four work days in common years {{nowrap|(25–28)}} and five in leap years {{nowrap|(25–29)}}, {{nowrap| 1 March }} was a uniform day off followed by only four work days in the first week of {{nowrap|March (2–5)}}. But some enterprises treated {{nowrap|1 March}} as a regular work day, producing nine or ten successive work days between {{nowrap|25 February}} and {{nowrap|5 March}}, inclusive. The national holidays did not change, but they now converted five regular work days into holidays within three six-day weeks (none of these was on a free day, with a date divisible by 6), so May and November had just three days of work after three consecutive days off, unlike the earlier five-day week when the holidays "delayed the rotation" of colors and were inserted as an extra day splitting the four-day working period into two parts (or creating a longer break between two four-days of work for people whose standard day off was just before or after the holiday).<ref name=Riga/><ref name=Parry/><ref name=Kingsbury/>