T2ya, born Tetsuya Hashinaga (橋長 哲也, Hashinaga Tetsuya) on May 14, is a Japanese songwriter and keyboardist from Gunma Prefecture. In 1990s, he supported the agency Rising Production, which later renamed to Vision Factory. He wrote both the music and the lyrics of Olivia Lufkin's "I.L.Y. (Yokubō)" and "Re-act." He also composed Mika Nakashima's "One Survive."In addition, T2ya wrote Aya Ueto's "Pureness," "Kizuna," "Hello" and "Personal."