KDDI Corporation is a Japanese telecommunications operator. It was established in 2000 through the merger of DDI Corporation, a long-distance communications company; KDD Corporation, Japan's former state-monopoly international telecommunications provider; and Ido Corporation, a mobile network operator. In 2001, KDDI fully integrated its mobile operations by absorbing the regional companies of the DDI-Cellular Group, unifying them under Au brand. It currently stands as the second-largest mobile telecommunications provider in Japan in terms of the number of contracts, following NTT Docomo. KDDI provides mobile cellular services primarily using Au brand, alongside its sub-brands UQ Mobile and Povo. ISP network services are provided under Au One Net brand, while Au Hikari is the name under which its Fiber to the Home services are marketed. Historically, the company also offered ADSL broadband and IP telephony over copper, but these legacy services have since been discontinued. Wikipedia