This slip jig is a five part-er in the key of D mixolydian. That means the complete list of chord options will be D major, E minor, F# diminished, G major, A minor, B minor and C major. As slip jigs contain bars of nine quavers (8th beats for American viewers) and those are subdivided into groups of three, this means that there are three potential chord slots per bar.
Compared to the other three “celtic” modes, the mixolydian is a bit less definite about HAVING to go from chord V to chord I to finish sections, and this tune is really rather vague in terms of which chords are outlined in the melody of which bars. For this reason my basic chord choices for this one might seem a bit unorthodox.
In the A part I have switched to a C chord for the last three quavers of the first bar. This is because the melody plays a long C note for the whole of this section. I have stuck with the C until resolving to D at the end of the second bar.
The B part actually ignores the first rule and follows the dominant G in the melody at the end of the second bar. It is common in mixolydian to end a section on chord IV- you can experiment with this with other mixolydian tunes.
The C, D and E parts exhibit a similar disregard for the first rule of folk tunes (chord V goes on every sixth foot tap) and so I have more or less followed the main dominant note in each three quaver section (aka three potential chords per bar), trying to keep the rate of harmonic change fairly slow to make life easy.
In this version I have broken up long sections of chords using substitutions. In many cases I have substituted major chords for their related minors (the chords whose roots are two below their own in the key scale, eg Am replaces C, Bm replaces D, Em replaces G etc), or minor chords for their related majors (the same but in reverse- C replaces Bm, D replaces Bm, G replaces Em etc).
I also use the first inversion of chord I to link to chord IV. In the B part for example I play D – D/F# – G. D/F# is a D major chord, inverted so that the lowest pitched note in the chord is its major 3rd, F#. This sets up a nice walking bassline, D – F# – G and links the D up to the G for a more fluid sounding chord progression.
In this version I have taken an approach I like to play with in order to discover new chords. I have picked a note from the key scale, in this case E, the second note in the scale of D mixolydian, and left it ringing in pretty much every single chord in the tune. In this instance its easy to do by leaving the top E string unfretted. I have also kept my third (ring) finger on the D on the third fret of the B string as much as possible, as a handy pivot about which to change at speed. Again this gives some interesting and unusual jazzy chords, shown below.
In the third bar of the B part I link C major down to its related minor A minor by using the chord below the target minor chord in its first inversion. This is a very common trick to link a major chord to its related minor. In this instance I play a C (with extra notes) followed by G in the first inversion (aka G/B) and finally A minor.
At the end of the B part I have used a very cheeky F major 7 chord. This is borrowed from the dorian or aeolian modes and really shouldn’t be in a mixolydian tune at all… However as there is no F# note in this bar, the minor third note relative to the key centre D (F) doesn’t clash with anything and putting this chord at the end of the tune gives the progression a kind of blues-y throwaway feel which I really love in mixolydian tunes. You can experiment with this in other mixolydian tunes, but use it sparingly! If your ears tell you it doesn’t sound right then try it somewhere else.
The other substitutions in this version are standard tetrad additions- D mixolydian contains the same notes, and therefore the same potential tetrads as G major:
G major 7
A minor 7
B minor 7
C major 7
E minor 7
F# ½ diminished (rarely used in folk music- we’ll replace it with chord V in the first inversion, aka D/F#)
As we are in D mixolydian, the correct order would be:
E minor 7
F# ½ diminished or D/F#
G major 7
A minor 7
B minor 7
C (dominant) 7
Notice that in any mode other than ionian the VII chord ALWAYS becomes a dominant- in this instance our C major 7 from the key of G major has become a C7 in D mixolydian.
Please note that the “D/F#” shown below has the E string left in for continuity, so strictly speaking it should be called “D add 9/F#”. If you leave the E string in the B minor as shown below then it’s really a Bm11. Either that or a Bm7 would be fine, as adding extra notes from the key scale to a chord just gives you a jazzier sounding version of the same chord.