Here are four chord positions that all sound like D7
Here are the notes of each inversion:
1st form: F#m7b5 = F# – A – C – E
2nd form: Am6 = A – C – E – F#
3rd form: D9 = C – E – F# – A
4th form: D9 = E – F# – A – C
The above chords all contain the same four notes and function as D7th, but contain no “D” note. In other words, they imply a D7(9th) chord without the root. In the theoretical world of chords, the dominant seventh chord is unique. Of the four notes that comprise a D7th chord (D – F# – A – C), the notes that define its core function are the 3rd (F#) and the 7th (C). The remaining root and the fifth tones, are optional. The distance between F# and C is three two-fret skips called a “tritone” interval. So practically speaking, if you find the F# & C notes all over the banjo fretboard, you will have the core harmony of a D7th chord. Partial chords have interesting possibilities for banjo.
Learning to view the neck in partial chord fragments sets up a kind of visual guide in which identical forms serve to paint many different chords. The five note pentatonic scale and its variations provide a wealth of two and three note positions for improvisation. For more information on this and other topics, check out the “The Key To Five String Banjo”