Ojousama Kumikyoku - Sweet Concert [NTSC-J] [SLPM-66726]
Ojousama Kumikyoku (お嬢様組曲). Protagonists name is Kaoru, it is a name used for girls normally, he has no idea why his parents decided to name him like that. And just because of that when he was changing schools he gets enrolled to a girls high school by mistake. When the girls find out, he becomes the object for them all to fight over.