Cognomen 知久 (Tomohisa 
, 知久 , Тику 
) , in the entire world, is a rare surname. The cognomen 知久 is habitual in Singapore, where it is a very rare surname, Switzerland, and Belgium. Not in comparison with a country's population, it most frequently occurs in China, Japan, and Russia. Predominantly, 知久 is the forename as well as the last name.