Number 6

Number 6
In Chinese cosmology, 10 Heavenly Stems include Chinese Stem 6. Ji.
     In the corresponding 12 Terrestrial Branches (12 Earthly Branches), Branch 6. Si, the snake, is Animal 6, and also Zodiac Animal 6. 
                                     Dragon,   Snake,               Horse
Branches                   5                6                        7
Numbers                    Quinque  Sex                    Septem                                   
                                     Dragon -  Snake               Horse
                                     (Heaven- Earth)     
The symbol for Chinese Stem 6. Ji and the name for Chinese Branch 6. Si become starting points for the number 6 and letter 6 in various languages:
Stem 6        - Branch 6  
Ji -                  Si
己 -                 巳
Sprout            Bloom
In old Chinese, Huang Ti, letter 6 becomes CHI in the form of a snake: 
The old Greek letter, Stigma, with a value of 6 is clearly related: 
Stigma uc lc.svg
So too is the letter f, So (i.e. sex) in Coptic which is linked with letter 6 Vau in Aethiopian.  
Also clearly related is old Slavic Selo which become the Cyrillic, Dzelo                     
e.g. Sesha (Persian),
        Sisha (Hebrew).