What key is Opus One in?

D major is one of guitar's most resonant keys. The open D string acts as a droning root, and the open A string provides the fifth. This gives D-based strumming a wide, ringing quality that flatpicks and fingerpicks love. D is a beginner-level key on guitar because the open D and A strings provide a powerful bass foundation, and the open high E is the 2nd scale degree adding brightness. Beginners will find this key approachable since most chords use open voicings with minimal stretching.

Voice Leading

The bass line moves through D to G (ascending perfect fourth), G to E (descending minor third), E to E (ascending unison), E to A (ascending perfect fourth), A to A# (ascending half step), A# to F (descending perfect fourth), F to D (descending minor third), D to G (ascending perfect fourth), G to C (ascending perfect fourth), C to F (ascending perfect fourth), F to D (descending minor third), D to C (descending whole step), C to G# (descending major third), G# to F (descending minor third), F to A# (ascending perfect fourth), A# to D# (ascending perfect fourth), D# to G# (ascending perfect fourth), G# to A (ascending half step). A half-step bass movement creates a strong leading-tone pull that demands resolution. The root motion by larger intervals (fourths and fifths) gives each chord change a strong, decisive character. When the progression loops, the bass returns from A to D by perfect fourth.

Scales for Improvisation

D major pentatonic works because every note is either a chord tone or a safe passing tone — there are no avoid notes. For soloing, this means you can play freely without clashing. Over dominant seventh chords, D Mixolydian adds the flat seventh for an authentic blues-rock edge.

swing2/2 · 29 bars · Form: AABA

Chords: Re, Sol9, Mi9, Mim7, La9, La♯9, Fa, Rem7, Solm7, Do7♭9, Fa6, Re7♯5, Do9♯5, Sol♯, Fam7, La♯m7, Re♯7♭9, Sol♯6, La13.

Scales for Improvisation Re bebop, Re bebop major.