A.B.C-Z is a four-member Japanese boy band under Starto Entertainment. The group was originally called A.B.C. (Acrobat Boys Club), but during the summer concert "Summary 2008" it was announced that Hashimoto Ryôsuke would join them and so they became A.B.C.-Z. Current members: 橋本良亮//Hashimoto Ryôsuke (1993.07.15) 塚田僚一//Tsukada Ryôichi (1986.12.10) 戸塚祥太//Totsuka Shota (1986.11.13) 五関晃一//Goseki Koichi (1985.06.17) Former member: 河合郁人//Kawai Fumito (1987.10.20)