The Luna Calendar problem

In the previous blog, I mentioned Jack Ma’s birth day of his official record 1964/9/10 is wrong.  He was born on 1964/9/10 of Chinese Luna calendar which is 1964/10/15 of Greg calendar. In fact, this mistake is very common in China. For example: my mother’s birthday is May 21 according to her ID, but her real birthday is July 3. 1961/5/21 of Chinese Luna calendar is 1961/7/3. My mother in law’s birthday is also wrong. Among the Chinese who was born in the 1960s, more than half of them have their Luna calendar birthdays as their birthday on ID.

Chinese Luna Calendar is a modified version of Islamic Calendar. And it is easier to convert a birthday to life code if you calculate it manually. Your birth month (Chinese Luna Calendar) + 2 = your zodiac month code. Why? Because the first month in the Chinese Luna Calendar is the (3) month, as we know, the (3) month is the first month in a year. In another word, if you are born in the 1^st month of Chinese Luna Calendar, your zodiac month code is (3). And so on.

We have leap years because a year is not 365 days. A year is 365.242 days. Therefore, every four year the difference will be accumulated to a day. Traditionally, Luna Calendar has 360 days: 30 days in a month and there are 12 months. So there will be extra month in a leap year. It is very difficult to deal with people who’s born in a leap month. That’s one reason why I prefer Greg Calendar than Luna Calendar. But now we can measure solar terms accurately, for example, the Start of Spring of 2012 is at Feb 4, 18:22:23. And the Start of Spring of 2013 is at Feb 4, 00:13:25. So a month of a Luna Calendar is 30.xxx day instead of strict 30 days. And a leap month is not necessary anymore.