Gree Inc. (3632), Japan’s second-largest social-network game operator, rose to the highest level in more than a week in Tokyo trading after the company said it will form an alliance with Dentsu Inc. (4324)

Gree rose 2.1 percent to 2,240 yen at close on the Tokyo Stock Exchange, the highest level since March 13. Dentsu gained 1.2 percent to 2,631 yen, the biggest advance since March 9.

Dentsu, Japan’s biggest advertising company, will help promote Gree worldwide and collaborate on aspects of business including content acquisition and “potential investments,” the Tokyo-based Internet company said in a statement today.

Gree, which has more than 190 million users, released the “Zombie Jombie,” the first social game developed at its U.S. studio, the company said on March 16. Gree acquired OpenFeint Inc., the Burlingame, California-based online-games network, for $104 million last year.

To contact the reporter on this story: Naoko Fujimura in Tokyo at nfujimura@bloomberg.net

To contact the editor responsible for this story: Michael Tighe at mtighe4@bloomberg.net