Yass is often defined as a new music style, but it is rather a compilation of many styles, such as jazz, improvised music, techno, punk rock, and folk.
This term appeared in late 1980 and was used to define a new stream in Polish music, which had been raised in Gdańsk and Bydgoszcz. The author's name was Tymon Tymański, a double-bass and guitar player from Gdansk, who wanted to stress a novelty of the new style.