Naming Vietnamese Lunar Years (Âm Lịch Việt Nam)
The year of the Dragon lasted from January 23, 2012 until February 10, 2013, when it was replaced by the year of the snake. The past year that was dynamic and powerful as the Dragon itself was Nhâm Thìn, the new one is Quý Tỵ, as provided by the Vietnamese Lunar Calendar.
As naming the years is not as popular in other parts of the world, things for them might appear a little complicated to put together regarding how the years are named.
Whereas the previous year (2011) was called Tân Mão and how the following year’s name of Quý Tỵ (year 2013) is already figured out, the system of naming the years along with the cycles in the Lunar calendar would, in reality, only require a few basic understanding of this remarkably interesting calendar.
Naming a Vietnamese year is basically done by combining two cycles, the "Ten Heavenly Stems" and the "Twelve Earthly Branches".
Twelve Earthly Branches
The "Twelve Earthly Branches" ("shi er di zhi") denotes the twelve signs of the zodiac consisting of: Tý (Rat), Sửu (Ox/Buffalo), Dần (Tiger), Mẹo/Mão (Cat/Rabbit), Thìn (Dragon), Tỵ (Snake), Ngọ (Horse), Mùi (Sheep/Goat), Thân (Monkey), Dậu (Chicken), Tuất (Dog) and the Hợi (Pig/Boar).
Ten Heavenly Stems
Meanwhile, the "Ten Heavenly Stems" ("shi tian gan" ...), comprised of Giáp, Ất, Bính, Đinh, Mậu, Kỷ, Canh, Tân, Nhâm and Quý
are further associated with the concept of Yin and Yang as well as of with the five "Basic Elements" where Giáp and Ất belongs to "Wood", Bính and Đinh to "Fire", Mậu and Kỷ to "Earth", Canh and Tân to "Metal", and Nhâm and Quý to the element "Water". In relation to the two basic properties "yang" (Am) and "yin" (Duong), Giáp, Bính, Mậu, Canh and Nhâm are known to hold the qualities of "yang", while Ất, Đinh, Kỷ, Tân and Quý possess the "yin" qualities.
Naming the year
So putting two and two together, combining this year’s heavenly stem (Canh) in parallel with its property (Yang) and Basic Element (Metal) to its earthly body Dragon (Thìn), 2012 Nhâm Thìn is labeled as "Yang Water Dragon".
Combining in a round-robin manner the two shorter cycles of the "Can", or the ten-year cycle denoting the "Ten Heavenly Stems" and the "Ky" or the twelve-year cycle in congruent with the "Twelve Earthly Branches", a greater cycle of 60 years is formed. Derived from the least common multiple of 10 and 12, the 60-year cycle (called Can Chi) is more like how the centuries are divided into every 100 years.
The cycle
As it cycles continuously, a particular year will return every after 60-year period. Each year in the Can Chi corresponds to a particular year name as follows:
Giáp Tý
Ất Sửu
Bính Dần
Đinh Mão
Mậu Thìn
Kỷ Tỵ
Canh Ngọ
Tân Mùi
Nhâm Thân
Quý Dậu
Giáp Tuất
Ất Hợi
Bính Tý
Đinh Sửu
Mậu Dần
Kỷ Mão
Canh Thìn
Tân Tỵ
Nhâm Ngọ
Quý Mùi
Giáp Thân
Ất Dậu
Bính Tuất
Đinh Hợi
Mậu Tý
Kỷ Sửu
Canh Dần
Tân Mão
Nhâm Thìn
Quý Tỵ
Giáp Ngọ
Ất Mùi
Bính Thân
Đinh Dậu
Mậu Tuất
Kỷ Hợi
Canh Tý
Tân Sửu
Nhâm Dần
Quý Mão
Giáp Thìn
Ất Tỵ
Bính Ngọ
Đinh Mùi
Mậu Thân
Kỷ Dậu
Canh Tuất
Tân Hợi
Nhâm Tý
Quý Sửu
Giáp Dần
Ất Mão
Bính Thìn
Đinh Tỵ
Mậu Ngọ
Kỷ Mùi
Canh Thân
Tân Dậu
Nhâm Tuất
Quý Hợi
Used in China since the second millennium B.C. as its manner of naming their days (pretty much how the Western world names the days of their week). The method utilizing the Sexagenary (Stem-Branches) cycle is evident throughout the Zhou dynasty as their records were found to be written in such manner. Its popularity is seen much widely around 202 BC-8 A.D. during the period of Western Han Dynasty. How and when it was adopted by several other East Asian countries (Japan, Korea, Vietnam...) varied throughout history.
Since a particular year returns after every Can Chi or passing sexagenary cycle, a year that began in 1984 will therefore enter a new cycle by year 2044. In the same manner, the previous Nhâm Thìn took place during 1952 which is exactly 60 years from today. When this cycle ends, the next Tân Mão, then, won’t be around until year 2072.