Il gatto sul G. (Ｇ線上の猫, G Senjō no Neko, translated as "Cat on a G") is a Japanese manga series by Tooko Miyagi.
Originally serialized in Taiyo Tosyo Anthology Craft on a quarterly basis in 1999 in Japan, the first volume was published by Taiyo Tosho Co., Ltd. in 2002.
The story of Il gatto sul G revolves around a talented, but strange, violinist named Riya Narukawa who collapses in front of Atsushi Ikeda's door with bloodied hands.
Music may be an escape for many people, but it traps, cages, and controls Riya.
In fact, the young, privileged musician endures struggles with a certain upperclassman who won't leave him alone and especially with himself—his other self.