It's hard to explain..but For me its more then just memorizing exactly what the charts read, ...I cant explain it but although I can read charts especially when playing with a band,....but as a solo I never need them. If this makes any sense, for me I can just hear the music in my head and my fingers just know what chords to play in the song in turn that let's me sync my vocals & lyrics all together effortlessly to perform a song,....hope I'm making this understandable?