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A few days ago in an interview, Phil Harrison expressed his disappointment with Sony Japan as he had earlier on tried to promote party games like Rock Band and Sing Star, but the Japanese division informed him that in Japan, no one plays in party groups. Then comes the Wii, and it sells very well. The resignation could be due to the interview. Sony Computer Entertainment may not have been happy with what Phil had said in the interview and maybe he felt that he should resign.