Complex sentence: Jun Aoyama was later replaced by Eiji Shimizu on drums in 1981, and pianist Hirotaka Izumi joined the band as their first long term keyboardist/pianist.
Split into simpler sentences: Jun Aoyama was later replaced by Eiji Shimizu on drums in 1981. Pianist Hirotaka Izumi joined the band as the first long term keyboardist/pianist.