Soviet revolutionary calendar

Already shortly after the Russian Revolution Lenin decreed to change the calendar in the Soviet Union from the julian calendar to the gregorian calendar by omitting February 1 till February 13, 1918. However eleven years laters starting on October 1, 1929 they did introduce a new rationalized version of the calendar, in which all month have 30 days and the remaining 5 days are added as holidays in between, not belonging to any month or week. These days were

• Lenin day after January 30
• Labour Day, two days after April 30
• Industry days, two days after November 7
• in leap years a leap day after February 30

Also as an anti-religious measure the seven day week was abolished and exchanged with a 5 day week, to take a away the christian Sunday as day of rest. Instead all workers got assigned into one of five colours (yellow, pink, red, purple, green), and every group had one of the remaining weekdays as their day of rest. By this the industrial production wouldn't been interrupted by a common day of no work, thus making the machines more efficient.

Even though 1 day off in 5 days did give the workers more leisure time then one day off in seven, the separation into five groups made familiy reunions as well as meeting friends difficult and was thus very unpopular, and also the planned higher efficiency of the shorter week did not show up in real.

Starting December 1 1931 the western schedule of month lengths was restored, but the week cycle wasn't restored, but changed to have a common day of rest on every 6th, 12th, 18th, 24th and 30th of the month, the 31st was kept outside this six day week cycle, sometimes being a holiday, sometimes a working day. But the Sunday was hard to rule out, many workers did take both Sunday and the new day of rest, so finally in 1940 the old seven day week was restored as well.