Last name 若斯 (若斯 
, Ruosi 
) , in all the world, is a rare surname. The family name 若斯 is characteristic of Italy, where it is a rare surname, China, where it is a very rare surname, and Argentina, where it is an extremely rare surname. Not in comparison with a country's population, it is the most numerous in Italy, China, and France. Also, 若斯 is the forename as well as the last name.