Although China has adopted the Gregorian calendar in common with most other countries in the world for official and business purposes, the traditional Chinese calendar continues to define the dates of festivals and is used for horoscopes. The calendar has a very long history going back to the Xia (21st century BC-16th Century BC) and Shang Dynasty (16th century BC-11th century BC). It is based on a unique combination of astronomy and geography through observation and exploration. It is also referred to as the Lunar Calendar, Yin calendar, Xia calendar or the old Chinese calendar.
Following its creation in the Xia Dynasty, succeeding reigns continued to use the calendar but modified it from time to time. The Han Dynasty rulers instituted the Taichu calendar, while during Tang Dynasty the Huangji calendar was introduced and it was adopted by Japan, Korea and Vietnam. With the founding of the Republic of China in 1912, the Gregorian calendar was brought into use. Although ethnic groups such as Tibet and Dai have their own calendars, in essence they resemble that of the Han people. Islam reckons its own religion festivals according to the Islamic Calendar.
The calendar has links with natural sciences such as agriculture and astronomy, solar terms, the four seasons and traditional festivals such as the Spring Festival. There are links also with the Five Elements’ of which the ancient Chinese believed the physical universe to be composed, that is, metal, wood, water, fire and earth. Finally, of course, there is also relationship with calendar and Sheng Xiao – the symbolic animals associated with each year on a 12-year cycle.