Last name Yotsui (Yotsui 
, 四井 
) , in the entire world, is a very rare cognomen. The last name Yotsui is characteristic of Brazil, where it is a very rare surname, the United Kingdom, where it is an extremely rare surname, and the United States. Measured by absolute frequency, the name is most common in Brazil, China, and the United States. More prevalently, Yotsui is the forename as well as the last name.