The musical alphabet consists of 12 notes: A, A♯/B♭, B, C, C♯/D♭, D, D♯/E♭, E, F, F♯/G♭, G, G♯/A♭. These notes repeat in a cycle on the guitar fretboard, which is essentially a linear piano keyboard. Each fret represents a half-step (semitone) change in pitch. Starting from the open strings (E, A, D, G, B, E), moving one fret up raises the note by one semitone, and this pattern continues across all six strings. Understanding this layout is key to mastering scales, chords, and improvisation on the guitar.