(Music Sales America). These pocket-sized swatch-packs are great for quick reference at home or on the go. Each Notecracker contains 70 handy reference cards, printed on both sides for quick access to chord diagrams, general music theory, jokes, quotes or snippets of musical trivia. Notecracker Blues Harmonica teaches you the techniques you need to begin to play the C Harmonica and how to use these techniques to play the blues. Presented on easy-to-read cards with clear diagrams and a simple tablature method, you'll quickly learn to play classic blues tunes in the style of Sonny Boy Williamson I, Sonny Terry, Little Walter and other blues harp greats.