On the modern five-string instrument, banjo chords and their shapes are dependent upon the tuning the player is in. The most common tuning in contemporary playing is open-G (gDGBD), which allows the player to easily embellish a chord progression and play lead breaks and solo’s, whilst retaining the tone of the root note (in this case, G), usually as a pulse.
Like the guitar, there are several different tunings for the instrument, so the fingerings for banjo chords vary from one to another; however, where the guitar is primarily more of a chordal instrument (where chords are strummed), the banjo is most often used to pick out individual notes in arpeggios that compliment the strummed chords. This is simply due to the respective tonality of the instruments – with the banjo being more twangy and piercing. This is not to say banjo chords can’t be strummed. In fact a gently strummed banjo can lend a subtle and beguiling dynamic to a slower piece.
When used in bluegrass (a very common genre for which the banjo is utilized) banjo chords make frequent use of the minor seventh note, and in turn the dominant seventh chord to relay the unmistakable, Appalachian-roots element they provide. When employed in traditional Irish and country music (the banjo is a mainstay of both) banjo chords will tend to be more fundamental, but still adding a unique, irreplaceable flavour.
It would be tempting to think of the banjo as a kind of intermediary between the ukulele and the guitar; after all, it’s in the middle of both when it comes to size and number of strings. However, this isn’t quite accurate, the reason being that the ukulele is played, almost exclusively, via strumming thus its tuning as far more akin to that of a guitar, and ukulele chords are derivations of guitar chords. Banjo chords, and the instrument itself, happen to share a similar appearance to the guitar and ukulele, but it’s really a different beast, and requires a different approach (in terms of musicality) when played. Understanding banjo chords, is essential to this.