The music did not develop a mainland audience during the Hawaiian music craze of the early 20th century, during which Hawaiian music came to be identified outside the Islands with the steel guitar and the ukulele. Slack key remained private and family entertainment, and it was not even recorded until 1946–47, when Gabby Pahinui cut a series of records that brought the tradition into public view. During the 1960s and particularly during the Hawaiian Cultural Renaissance of the 1970s, slack key experienced a surge in popularity and came to be seen as one of the most genuine expressions of Hawaiian spirit, principally thanks to Gabby Pahinui, Atta Isaacs, Leonard Kwan, Sonny Chillingworth, Raymond Kāne, and the more modern styles of younger players such as Keola Beamer, his brother Kapono Beamer, Peter Moon, and Haunani Apoliona. During this period, luthiers such as the Guitar and Lute Workshop in Honolulu specialized in the development and manufacture of guitars custom made to order for slack-key performance.