Ask HN: TP - Google did not find

What is the minimum possible character length of a search keyword with which Google search can return a message "Your search did not match any documents."? Of course, 1) keyword MUST use only characters and numbers 2) No special characters 3) Google shouldn't ask "Did you mean?"

My lowest count was 6 with "i9qew8" (until this page gets listed by Google :P) Yours?