Eiken Co., Ltd. is a Japanese anime studio in Arakawa, Tokyo, Japan. The company was formerly known as Television Corporation of Japan Co., Ltd. or TCJ before changing its name in 1969 to establish Eiken. It is a wholly owned subsidiary of Asatsu-DK.

ADK Holdings Inc. d/b/a ADK, formerly known as Asatsu-DK, is a Japanese advertising agency. Headquartered in the Toranomon Hills building complex in Minato, Tokyo since June 2014, the firm is Japan's third largest advertising agency after Dentsu and Hakuhodo. The agency has 80 offices in over 20 countries. One, Asatsu-DK Europe, was established in 1993 in Amsterdam, Netherlands. Bain Capital has owned the company since 2018.