Why? Because the guitar is a horizontal grid. By limiting yourself to one string, you destroy position-playing habits. You are forced to listen to intervals rather than finger shapes. You learn where every note truly is. Goodrick argues that until you can navigate fluidly on one string, you don't really know the fretboard.
Goodrick's pages also taught a different kind of mapmaking: modal pathways that looped and intersected, voice-leading tricks that turned static harmony into moving architecture. But these were not tricks to dazzle; they were tools for subtlety. He began to hear his instrument less as a tool for displaying skill and more as a conversation partner. He learned to ask questions with a bend in a note, to answer with silence, to let a harmonic choice imply a history rather than state it outright. mick goodrick the advancing guitaristpdf