Surname Нацуи (Natsui 
, 夏井 , Нацуи 
) , in the world, is a very rare family name. The family name Нацуи is characteristic of Brazil, where it is an extremely rare surname, Nigeria, and the United States. In absolute terms, it is the most numerous in Brazil, China, and the United States. Much more frequently, Нацуи is the forename as well as the last name.