This tune doesn’t have any strong chord IV sections in the A part, so in the simple version I have simply stuck to the “folk formula”- chord V on every seventh foot tap, resolving to chord I at the end of each section. The B part’s third and fourth bar very clearly outline a G major chord. The notes of the melody here are G A B D B A, G A B D B D. The notes of a G major chord are G, B and D. NB- when picking chords to accompany a tune, the most important notes to listen to for chord choices are the ones on the dominant beats which I have written in bold text. In the interests of simplicity for the beginner guitarist I have used E minor instead of G major- this is valid as E minor is G’s related minor, so the two chords can be used interchangeably. Aside from these two bars, the B part also follows the standard formula.
In the A part of the tune I have switched A minor to F major. This is actually a chord borrowed from the aeolian mode. In the key of A dorian, the F chord should be an F# diminished as in A dorian’s related ionian mode, G ionian. However if we were in A aeolian the 6th chord would be F major. A minor chord can always be substituted for either the chord which is two above it in the scale (its related major chord) or that which is two below it in the scale (another chord with which it shares two notes in common). In this instance I have used the chord two below as it would be in the aeolian mode instead of as it would be in the dorian mode. The reason that this nifty trick works is because there is only one note different between the dorian scale and the aeolian one. Compared to a major scale, the dorian mode has a flattened 3rd and flattened 7th while the aeolian has a flattened 3rd, flattened 6th and flattened 7th. It is this flattened 6th which gives the aeolian mode its darker character than the dorian. By borrowing the F chord from A aeolian, your accompaniment will give the tune a darker flavour than it would have had if you had used the F#dim (or a substitute thereof) which you would expect in the dorian mode. You can get away with this in the third bar of the Cliffs of Moher because there is no 6th note in the melody anywhere in this bar. This is a common feature of Irish melodies, that in minor (dorian or aeolian) tunes, the 6th note rarely appears, meaning that you can often use the chords of either the dorian or the aeolian mode, or a combination of both, for artistic effect. You can find out more about this technique in my free video on the subject here.
In the B part I have followed the G chord outlined in the second bar, and then replaced it with its related minor (Em) in the third. I have substituted an F (again, borrowed from the aeolian mode) for the A minor in bars 5 and 6. Bars 7 also outlines the notes of a G chord, so I’ve added one in.
In this version, I wanted to go for a “gypsy jazz” flavour, so I have begun with the “Django chord”, aka an A minor add 13 (I’ve notated it as Am13 on the video to save space- the difference between an actual Am13 chord and this Am add 13 chord is that Am13 should contain the flattened 7th note, G, as well as the root, ♭3rd, 5th and 13th, but this chord does not).
I have replaced the F majors throughout with F major 7. This F chord is borrowed from the mode of A aeolian. A aeolian is related to C ionian and therefore has the same chords as that mode. In C ionian, F would be chord IV and therefore if you wanted to play a tetrad (jazzy 7 chord) for it, it would have to be F major 7- hence that is the chord which I have used in this context.
Once you have descended into jazz land, any chord which resolves down a fifth can be replaced with a dominant or altered dominant chord. For this reason I have replaced my chord Vs in this version with an E7#5 chord. This is a really classy chord V and, due to its flattened seventh and altered chord tone, the #5th, very much sounds like it wants to resolve back to chord I immediately afterwards (resolving down a fifth, from V to I).
When the A part repeats, I have made a change to the chords for contrast. In the 5th bar of the A part repeat I have borrowed the D minor chord from A aeolian (acceptable as there is no 6th note of the A dorian scale in this bar of the melody) and played an ascending aeolian chord run from the Dm7 – Em7 – Fmaj7 before ending the section with my altered dominant V – I.
For the B part I have used a more traditionally dorian set of chords. Whenever you are playing in any mode other than ionian, chord VII becomes a dominant chord (9, 11 or 13). For this reason I have used G13 in the third and fourth bars. I also like G13 and Am add 13 together as they are particularly easy chord shapes to switch between at speed.
The D9 chord used in bars 7 and 8 gives the section a characteristically dorian feel. Recall that A dorian contains the same chords as G ionian, meaning that the IV chord in the dorian mode is equivalent to the V chord in the aeolian mode, and therefore has to be a dominant 7 type tetrad. For this reason my inclusion of a D9 here provides a very clear jazzy dorian vibe.
When the B part repeats, the tune contains a section in bars 5-6 of the repeat which is basically a descending scale from the 5th (E) down to the second (B), punctuated with E notes (E – E D E E, C E E B E E). I have sought to replicate this descending figure in my chords by descending from Fmaj7 to Em7. The next bar is an ascending scale and includes the 6th note of the A dorian scale, F#. For this reason I have played D/F# in my chords for this bar. As that sets up an ascending bassline from E – F#, it seemed right to use G13 instead of an Em or E7 type chord for the last chord V section. This continues the upward motion in the bass and then takes me back to my root note, E – F# – G – A.