Inagaki joined the WPP board in 1998 when the ad giant took a 20% stake in Asatsu-DK, Japan's third-largest agency behind Dentsu and Hakuhodo.
During his time on the board Inagaki has helped develop the strategic alliance between Asatsu-DK and WPP.
The agency had previously been aligned with the BBDO. Since then the two came together they have launched a number of joint ventures including the opening of MindShare's Japanese office.
His replacement, Naganuma, is president and group chief operating officer of Asatsu-DK. He joined Asatsu in 1981 and his roles have included executive director of the international division, managing director of Asatsu worldwide company and president of the overseas network. His WPP board appointment will continue the strong strategic alliance between Asatsu-DK and WPP.
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