Japanese emigrants to USA

[Acinom]

What was a Japanese emigrant to the USA called beginning with the letter i

[Lonnie]

Issei, meaning, 'The Army Sent', afraid thats all I could find on it.

[Quizmonster]

An issei was a Japanese immigrant into the USA who did not qualify for citizenship until 1952 and I believe the word is actually Japanese for 'first generation'.

(It doesn't apply to your question, but just out of interest, a nisei was an American born of Japanese parents, the word meaning 'second generation' and a sansei is an American born of a nisei, the word meaning 'third generation'.)

Obviously, though, the answer you need is issei, as Lonnie said above.