Tech Search

I... n the deal, Yahoo Japan would use Google's search engine and advertising platform. Microsoft argues that the combination of the first- and second-biggest search advertising platform will give Google 98 percent of the online advertising platform, which would lock out any new competition.

A spokesman said Microsoft plans to present evidence showing that the deal is even more anti-competitive than Google's proposed advertising partnership with Yahoo in 2008, which the Justice Department rejected.

"Google's plan would cement its position as essentially the sole provider of search results in Japan for years to come," Dave Heiner, Microsoft's deputy general counsel, said in a blog earlier this week.

Google said it consulted Japan's Fair Trade Commission about the deal and any antitrust implications and that regulators did not object to the partnership.

The Redmond, Wash.-based software company has been trying to break into the search advertising market, and has teamed up with Yahoo on a global partnership for search and advertising to better compete against Google's dominance in many global markets. Google has about 65 percent of the search market in the United States.

The deal between Google and Yahoo Japan won't complicate Yahoo's deal with Microsoft except in Japan, according to Yahoo.

Yahoo owns 35 percent of Yahoo Japan, which is majority-held by Softbank.

"We remain confident in our transition plans for the search alliance, are driving innovation in the user experience around search on the Yahoo network, and continue to be committed to our alliance with Microsoft," Yahoo said in a statement.