He learned piano, and was taught to play ukulele and ki ho'alu (traditional slack key guitar styles) by his grandfather and his Uncle Pete Hauʻoli.
The result, in 1958, was Kwan's first Tradewinds single, the original instrumental "ʻOpihi Moemoe," which would become his signature piece and a standard tune in the slack key repertory.
Other tracks featuring Kwan as soloist or sideman were released on two early-1960s Tradewinds compilations, Party Songs Hawaiian Style, Volumes 1 and 2.
There was some loosening of this attitude in the 1960s, and by the 1970s the old secrecy was rapidly disappearing, and in 1975 Kwan was the first player to publish the tunings he used on a recording, on the sleeve notes to The Old Way, which also included a transcription of the new version of "ʻOpihi Moemoe" that was on the album.
In 1980, Kwan and collaborator Dennis Ladd followed Keola Beamer, who in 1973 had published the first how-to book for the tradition (First Method for Hawaiian Slack Key Guitar) by producing Slack Key Instruction Book, which presents ten of Kwan's compositions and arrangements in a range of tunings, in standard notation and tablature, with performance notes and photographs of correct left-hand positions for the chords.