What is "hagaw"

Hagaw, also known as Asocjacja Hagaw, is a Polish traditional jazz band, formed as a quintet at the Klub Stodoła in Warsaw in 1964 by Andrzej Jastrzębski, and named from the initials of the first names of its founding members. The original lineup consisted of Jastrzębski, Grzegorz Brudko, Henryk Kowalski, Wiesław Papliński and Andrzej Bielecki. The lineup has since changed many times.