The move represents a consolidation of the business, which was previously split between Initiative and MindShare.
A MindShare spokesperson said the business represented less than 10% of its revenue in Japan.
Nippon Lever puts its accounts up for review every three years. Initiative, which uses Hakuhodo as its media-buying partner, picks up a number of new brands in the consolidation, including Dove, Lux and Ponds.
There was no change in the creative accounts, which remain with Ogilvy & Mather, J Walter Thompson and Hakuhodo:Lintas.
The two media agencies are also fighting it out for Unilever's £25m business in Thailand.
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