Cognomen Ryuzo (Ryuzo 
, Рюзо) , in the entire world, is a rare last name. The last name Ryuzo is characteristic of Japan, where it is a rare surname, Singapore, where it is a very rare surname, and Hungary. Measured by absolute frequency, it is the most numerous in Japan, China, and Hungary. Much less frequently, Ryuzo is the forename as well as the last name.