NIO

Kongōrikishi are usually a pair of figures that stand under a separate temple entrance gate usually called Niōmon  

 in Japan, Heng Ha Er Jiang  in China and Geumgangmun  in Korea. 

 The right statue is called Misshaku Kongō  and has his mouth open, representing 

the vocalization of the first grapheme of Sanskrit Devanāgarī (अ) which is pronounced "a". 

The left statue is called Naraen Kongō  and has his mouth closed, representing the vocalization of the

 last grapheme of Devanāgarī (ह [ɦ]) which is pronounced "ɦūṃ" (हूँ). These two characters together symbolize the birth and 

death of all things. (Men are supposedly born speaking the "a" sound with mouths open and die speaking

 an "ɦūṃ" and mouths closed.) Similar to Alpha and Omega in Christianity, 

they signify "everything" or "all creation". The contraction of both is Aum (ॐ), which is Sanskrit for The Absolute.