Last name Waichi (Waichi 
) , in the entire world, is a rare family name. The cognomen Waichi is characteristic of Japan, where it is a rare surname, Cambodia, where it is a very rare surname, and China, where it is an extremely rare surname. Measured by absolute frequency, the name is most common in Japan, China, and India. More prevalently, Waichi is the forename as well as the last name.