In Japan, because the daikoku (lit. "great black") from Daikokuten sounded the same as the daikoku (lit. "great land") from the ancient Shinto deity Okuninushi no mikoto (which can also be written "Daikoku no shu"), the distinction between the two blurred, and they were eventually combined.
日本においては、大黒の「だいこく」が大国に通じるため、古くから神道の神である大国主と混同され、習合した。