Heavenly Stems and Earthly Branches 天干地支

天干地支Heavenly Stems and Earthly Branches - Part 1 

Calendar system

Simplified as Stems and branches 干支, The Heavenly Stems (HS) and Earthly Branches (EB) was ancient Chinese calendar system. There are 2 calendar system used by the Chinese, the Lunar calendar and the Solar calendar. For BaZi reading, solar calendar is used.

The ten Heavenly Stems (HS) are

Jia 甲

Yi 乙

Bing 丙

Ding 丁

Wu 戊

Ji 己

Geng 庚

Xin 辛

Ren 壬

Gui 癸

And  the twelve Earth Branches (EB) also correspond to the twelve Chinese Zodiac animals which are:

Zi 子 - Rat

Chou 丑- Ox

Yin 寅-Tiger

Mao 卯 - Rabbit

Chen 辰 - Dragon

Si 巳 - Snake

Wu 午 - Horse

Wei 未 - Goat

Shen 申 - Monkey

You 酉 - Rooster

Xu 戌 - Dog

Hai 亥 - Pig

The 12 EBs were once widely used to denote hour, called 时辰 Shi Chen in Chen in Chinese, a day 24 hours consists of 12 ShiChens 1 ShiChen is equivalent to 2 hours. A new day starts at Zi hour and ends with Hai hour. 

The EBs were also used to present months, a new year starts with Yin month (also called the first month) and ends with Chou month (the twelve month). Yin month starts at the beginning of Spring 立春 which falls on the 3rd or 4th of February each Year. Note that the traditional Chinese New Year is a Lunar Calendar new year. 

As there are 4 seasons in 12 months, each season is presented by 3 EBs.

Yin - Mao - Chen are the months in Spring

Si - Wu - Wei are the months in Summer

Shen - You - Xu are the months in Autumn

Hai - Zi - Chou are the months in Winter 

Time adjustment

Sundial Device

Time adjustment is a controversial topic among BaZi practitioner but I personally believe in time adjustment. In ancient days, sundials were used instead of clocks, sundials tell the position of the sun locally, unlike clocks which are standardized across the whole country. Thus, time adjustment is needed to obtain the true Solar Time

Plotting a BaZi chart

Plotting a BaZi chart is easy, find an online calculator somewhere and plot in your birth date and time (after time adjustment) and you will have your BaZi chart. 

An alternative (more difficult method) is to use the ten thousand years Chinese calendar to find out your BaZi. 

A good software can be found here, if you wish to download the calculator, you'd have to register and participate in some discussion in the forum.