Surname Kotaro (Kotaro 
, Котаро 
, كوتارو) , globally, is quite a rare family name. The family name Kotaro is characteristic of Japan, where it is a rare surname, Indonesia, and Singapore, where it is a very rare surname. Not in comparison with a country's population, it is the most numerous in Japan, China, and Indonesia. Likewise, Kotaro is the forename as well as the last name.