Surname 刀 (Dao 
, 刀 , Katana 
) , in all the world, is a widespread cognomen. The family name 刀 is characteristic of Macao, where it is quite a common surname, Vietnam, and Montenegro (explore the name in all countries). Not in comparison with a country's population, the name is most common in China, Vietnam, and Japan. Very seldom, 刀 is the forename as well as the last name.