"1st, 2nd, 3rd ect. heavenly stems"

[Andy]

Hi.
I think, you noticed that there in The Traditional/Modern Radicals
were so called "heavenly stems".

what does it definitely mean (I guess, I know) and is it useable as
counting numbers, such as: first, second, third, fourth, fifth, sixth,
seventh, eighth, nineth, tenth, eleventh, twelfth.
And ect.

So, what is that and how chinese people use it?

[ppk]

its a set of symbols for calculation, the 10 heaven stems and 12 earth branches. they pair up with each other 1 by 1. after the 10th stem, the 1st one will be used to pair up with the 11th branch. after the 60th pair it goes back to the 1st stem and 1st branch again. it was mainly used in date and time calculations. the day is divided into 12 parts of 2 hrs using the 12 branches, the years are recorded in cycles of 60yrs etc. it is this system that allow us to trace chinese history accurately. example:

1st stem will only pair up with the 1st, 11th, 9th, 7th, 5th, 3rd branches. since people dun usually live over 60yrs old, by stating the year of the emperor and the pair up branches, we can be sure whether historical records are accurate. lets say, assuming qin shi huang 51 yr, pair 1 and 7, yr 220 bc. from calculations in 60yrs cycle, if the yr matches, like 220bc is actually a year of pair 1 and 7, then we know that its true qin shi huang 51 yr is 220 bc. if the calculation mismatched, like 220bc is actually a year of pair 1 and 5, then there is a 12 yr error in history records.