 Originally Kenji Kawai and Yoko Kanno were asked by Production I.G.  to do the music, but both of them refused because their scheduling  conflicts. Since Mamoru Oshii is a great fan of Hans Zimmer, he  asked the German composer who also couldnt accept the offer, but  recommended his friend Mark Mancina and Zimmer stayed as music  producer and also wrote some themes for the series.