Complex sentence: Kishidan is a six-member rock group with a nostalgic retro flair, wearing Japanese school boy uniforms extended in the style of yankees and biker gangs of bygone Japanese eras, that were common from the early 50's to the late' 90s.
Split into simpler sentences: Kishidan is a six-member rock group with a nostalgic retro flair, wearing Japanese school boy uniforms extended in the style of yankees and biker gangs of bygone Japanese eras. Kishidan represent the memory of biker bad boys of Japan that were common from the early 50's to the late' 90s.