At about every third year, an extra month is contained between the third and fourth months. This is to reconcile the lunar calendar with the solar one.

The Vietnamese like the lunar calendar as they can be sure of a full moon on the 15th day of every month. In their daily life but they utilize the Gregorian calendar.

Different from our centuries of 100 years, the Vietnamese calendar is divided into 60-year periods called "Hoi".

This "Hoi" or 60-year period consists of two shorter cycles; one of a ten-year cycle and the other of a 12-year cycle.

The ten-cycle, called "Can" is consisted of ten heavenly stems. Their names and approximate translation follow.

     1.    Giap    water in nature
     2.    At        water in the home
     3.    Binh     lighted fire
     4.    Dinh     latent fire
     5.    Mau     wood of all types
     6.    Ky        wood set to burn
     7.    Canh    metal of all kinds
     8.    Tan       wrought metal
     9.    Nham    virgin land
    10.   Quy      cultivated land

The 12-year cycle, "Ky", has 12 earthy stems featured by the names of 12 names in the zodiac. Their names and translations in order are:

     1.    Ty      the rat
     2.    Suu    the buffalo
     3.    Dan    the tiger
     4.    Mao    the cat
     5.    Thin    the dragon
     6.    Ty       the snake
     7.    Ngo     the horse
     8.    Mui      the goat
     9.    Than    the monkey
    10.   Dau     the cock (the chicken)
    11.   Tuat     the dog
    12.   Hoi      the pig

A Vietnamese year is named after the combination of one of the names of the ten heavenly stems and one of the names of the 12 earthly stems. For example, 1964 was the Year of the Dragon, "Giap-Thin". Giap is the first of the ten-year cycles and Thin is the fifth of the 12-year cycle. The year 1965 was "At-Ty". This follows down the line every year. The ten-year stem is not usually referred when telling about the year. Therefore we hear, "The Year of the Dragon" or the "Year of the Snake", etc., etc., Giap-Thin, the Year of the Dragon, will not return for a 60-year period. This is true of all combinations.

Source:travelvietnam

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