This is a very dark sounding slip jig in E aeolian. That means the chords available are E minor, F# diminished, G major, A minor, B minor, C major and D. This is because aeolian is the sixth mode, and therefore E aeolian contains the same chord options as G ionian (major) would. You can find out more about this in my first book, Backing Guitar Techniques for Traditional Celtic Music.
In the A part I have used only chords I (Em) and V (Bm). In a slip jig you can have up to three chords per bar, one chord for each block of three quavers (“8th beats” for Americans). You usually end the second bar with chord V and always end the fourth bar and multiples thereof with chord V going back to chord I. This is exactly what I have done here.
In the B part, I have replaced the B minor with its related major. This is a little easier to play and in my opinion sounds nicer in context. You can always replace a minor chord with its related major, the chord whose root is two notes above its own in the key scale. In this case we are starting from B, and two notes up the key scale of E aeolian we find D. Therefore we can replace B minor with D major.
In this version I have replaced the B minor at the end of the second bar with a D major. This works because D is B minor’s related major chord. I have played the D in the first inversion, with the F# note (the chord’s major 3rd) at the bottom. This sounds nicer than a normal D chord, because it is getting rid of the big jump in the bass notes. In order to understand this, think about an E minor and a D chord as two separate piles of notes, which create little melodies between themselves. Going from an E minor chord, which contains a low E note on the bottom string of the guitar, all the way up to the D string which is the lowest note in a standard D chord, is a huge leap for the ear. If you invert the D chord so that its lowest note is the F# on the bottom string’s second fret then you have made the jump a lot smaller. This will “glue” your chord progression together nicely. You can play D/F# with a standard D major shape- just loop your thumb round the back to that it depresses the second fret on the bottom string as shown below.
In bar four of the A part I have replaced an E minor with a G. G is Em’s related major (E – F# – G) so this is a valid substitution. It also follows the melody, which contains the notes “G – A B E D E – -”.
In the B part I have used D’s first inversion again in bar two. In the third bar, I have substituted C for E minor. This works because any chord can be substituted either for the chord whose root note is two above it OR two below it within the key scale. In this case our key scale, E aeolian, can make the chords E minor, F# diminished, G major, A minor, B minor, C major and D major. This means our E minor can be substituted to either G major or C major.
In the fourth bar of the B part I have flagrantly disregarded my own rule about chord V! Ending a section on chord IV gives it a deliberately unfinished feel, as if it’s day-dreaming about something that might happen down the line somewhere. In this context I thought it sounded rather nice- you can experiment with this in any tune in any mode. The second time through the A part however I do not end on chord IV as the tune would sound unfinished if I did so. Instead I go from chord V (Bm) back to chord I as usual.
In this version I have more or less just converted each chord from the previous version into the relevant kind of tetrad. E aeolian contains the same notes as G ionian would. The list of tetrads available in G ionian would be:
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#)
The same list applies to E aeolian.
In the B part I have used a C major 9 chord. So long as you have started out with the right kind of tetrad, adding further notes from the key scale to any given chord will just make it sound jazzier. In this case I have taken a C major 7 chord (containing the notes C, E, G and B, the 1st, 3rd, 5th and 7th notes of a C major scale) and added the 9th note as well, aka D. This works fine because a D note appears in the E aeolian scale so will not clash with the tune.