Family name Sîn (臣 
, シン 
, Sîn 
) , in the world, is a common surname. The cognomen Sîn is characteristic of Japan, where it is quite a common surname, Kyrgyzstan, where it is quite a rare surname, and Kazakhstan. In absolute terms, it is the most numerous in Japan, China, and Russia. Also, Sîn is the forename as well as the last name.