Japan's largest agency group Dentsu (global ranking number 5) is to join forces with its rival Asatsu-DK, currently ranked third in Japan and tenth worldwide).

Together the duo plan a major joint venture, launching October and focusing on content and "cross-media creative" -- a melding that will exploit digital TV, the internet, cellphones and other electronic media.

The deal effectively outflanks Japan's second largest ad network, Hakuhodo DY Holdings (world number 8), in the battle for agency supremacy in what many see as the next 'killer' media market.

Data sourced from: AdAgeGlobal.com; additional content by WARC staff