KDDI Agrees To Include FourSquare In New Japanese Android Devices KDDI, Japan's second largest carrier after NTT Docomo, has entered into a partnership with FourSquare to promote and support FourSquare's expansion in Japan. KDDI, Japan’s second largest carrier after NTT Docomo, has entered into a partnership with FourSquare to promote and support FourSquare’s expansion in Japan. FourSquare has not