Complex sentence: After he returned to Japan, he released a string of hits such as "Aoi Sanmyaku" and "Nagasaki no Kane", which were composed by Ryoichi Hattori and Yuji Koseki respectively.
Split into simpler sentences: After he returned to Japan, he released a string of hits such as "Aoi Sanmyaku" and "Nagasaki no Kane". The songs were composed by Ryoichi Hattori and Yuji Koseki respectively.