Tags: Genre, Music Genre, Topical Concept.
Avant-garde progressive rock (also called avant-prog and experimental prog) is a style appeared in the late 1960s as the extension of two separate prog rock sub-styles A host of groups and artists mainly from the USA but also from Europe and Japan started to write mostly short instrumental pieces that focused on complexity and stripped down instrumentation while avoiding the pomposity and stage props of the big progressive rock acts.