The year 2021 began with terrible news for pessimists: it turned out that the calendar of the year 21 of the 21st century is completely identical to the calendar of 1937. If anyone has forgotten, let us remind you that the Great Terror began in 1937, when Stalin’s repressions reached their greatest scale.

In turn, optimists found an “unbelievable” February in 2021: with four Mondays, Tuesdays, Wednesdays, Thursdays, Fridays, Saturdays and Sundays – supposedly this happens only once in 823 years.

Ouroboros – a snake or dragon curled up in a ring and biting its own tail. It is one of the oldest symbols and has many different meanings. The most common interpretation describes it as a representation of eternity and infinity, especially the cyclical nature of life.

We must be disappointed: in all years, except for leap years, the days of the week repeat four times in February, because the number of days in this month is 28 – exactly four weeks.


But maybe the authors of the myth had in mind that in 2021 February begins on Monday and ends on Sunday, and this is a great rarity? Will this year be unique, at least from the point of view of the calendar?

Is February February or Perfect?

Let’s go back to our pessimists and open the calendar for 1937: we look at February and see that it is no different from February 2021. So, the statement about the exclusivity of this year’s February has already become somewhat doubtful. But let’s scroll further: the calendars of 1943, 1954, 1965, 1971, 1982, 1993, 1999, 2010 and 2021 (and, accordingly, the days of February) are completely identical.

Attentive readers have probably already noticed a pattern: calendars repeat with a certain periodicity: 6 years + 11 years + 11 years (total – 28 years). So, modern calendars are a 28-year cycle, during which leap years repeat three times – first at six-year intervals, and then twice at 11-year intervals. The same period includes 7 leap years, each of which begins on a different day of the week – not consecutively, but in a certain order: Monday, Saturday, Thursday, Tuesday, Sunday, Wednesday, that is, every five days of the week.

Everything is really feng shui, but no mysticism or conspiracy – just ordinary mathematics!


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Yuriy P.
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