# Im6 chord in a minor II-V-I

In a minor II-V-I progression, we usually have a IIm7(b5) chord followed by a V7(b9,b13) chord, resolving into Im7. I always thought the diminished 5th in the II chord (also the minor 9th in the V7 chord, same note) was like a "hint" that a minor chord was coming, since it corresponds to the minor 6th of the I chord. That would be F in A minor/C major.

If you analyze the progression from a relative major standpoint:

``````VIIm7(b5) _ V7/VI(b9,b13) -> VIm7
``````

In a major harmony, the VIm7 is related to the Aeolian mode and should have a minor 6th, right?

However, it came to my attention that some standards, like Autumn Leaves and Caravan (no II here, but a long time spent on V7b9), have this chord written and played as Im6 sometimes, with a major 6th instead. Is there a particular reason for this?

Edit: Is this a chord substitution? Some substitutions are based in harmonic concepts, like the tritone substitution. Does this major 6th thing have such an underlying concept?

• Which chord is Im6 in Autumn Leaves? I've seen many different music sheets for the song, but never once seen a m6 chord there; it isn't on the real book either. Ι've never seen any major 6th chord either there. But if you saw a I6, it is a common substitution for Imaj7 Mar 7, 2015 at 0:00
• Em6 in G major versions, last chord of it's A section. Please note that it's Im6 in minor harmony (VIm6 in a major key like Autumn Leaves). youtube.com/watch?v=KoxY_xPmJXg Mar 7, 2015 at 0:06
• So, your question is why is there a C in the E minor chord? Mar 7, 2015 at 0:10
• A minor 6th chord is spelled 1 b3 5 6 which with a root of E is E G B C#. It's like any other substitution in Jazz it's function is similar, but the flavor is different.
– Dom
Mar 7, 2015 at 0:20
• I don't understand the downvote. This is a very relevant question. Mar 7, 2015 at 11:06

You are right that in minor the minor sixth of the key is part of the II chord, and it is a tension (b9) that is very often used on the V chord. However, it is not a valid tension on the I chord, because the minor sixth is an avoid note on that chord (basically because it is a half step above a basic chord tone, the 5). In this blog post you can read more about avoid notes.

On the other hand, the major sixth is a valid tension on the I chord in minor. A minor 6 chord always contains the major sixth. It comes from the melodic minor scale. The I chord in minor comes in three basic flavors: Im6 (with a major 6th), Im7 (with a minor 7th), and Im maj7 (with a major 7th). The corresponding chord scales are melodic minor (for Im6 and Im maj7), and dorian (for Im7).

• The linked blog post is an outstanding resource. It might be worth mentioning that a `I min6` chord doesn't require melodic minor. Dorian can also be used over a `I min6` chord. Jun 11, 2017 at 23:11
• @jdjazz: Thanks! ( I wrote that post :) And indeed, of course a minor 6th chord doesn't require anything, it's just that melodic minor is the most common and most natural choice, because it has no avoid notes when played over a m6 chord. Dorian contains all chord tones as well, but its 7th degree is an avoid note over that chord because it is a half step above the 6th. Melodic minor and dorian relate to a m6 chord a bit like Dorian and Aeolian to a m7 chord: both are possible but one is more natural because of the lack of an avoid note. Jun 12, 2017 at 7:44

I think the answer to your overarching question is: there's no requirement that the `ii` chord or the `V` chord share the same scale/chord tones as the `i` chord. The `ii-V-i` progression will still sound good even whether or not a common scale is used across all three chords.

For example, it's not uncommon to play a Locrian ♯2 scale over the `ii` chord, an altered scale over the `V` chord, and then a melodic minor scale over the `i` chord. If you take a `ii-V-i` in `G min`, this would be equivalent to playing these chords and scales, respectively:

`| Aø7 | D7alt | Gmin | Gmin |`

`| C melodic minor | E♭ melodic minor | G melodic minor | G melodic minor |`

There are plenty of notes that aren't shared across these three scales, but those scales nonetheless sound good over the ii-V-i.

That said, there might be reasons for choosing to play Aeolian vs. Dorian vs. melodic minor over the `i` chord. Matt L. mentions one possible reason for choosing dorian over Aeolian--because Dorian has fewer avoid tones. On the other hand, one might choose Aeolian for continuity with the `V alt` chord, as you suggest in your original post. Another factor one could consider when choosing a scale is the melody--if the melody uses a ♭6th over the `i min` chord, then maybe the solos should too. But there is no prescribed scale and the soloist often has freedom to choose which to use. So the Aeolian can be a great sound even despite its ♭6 avoid tone, but there's no rule that Aeolian is required over the `i min` chord to create continuity with the `iiø` or `V7alt` chords.

A couple notes:

A `i min6` chord is extremely common on Autumn Leaves, in large part thanks to Miles Davis, who in bar 7 plays the natural 6th in the melody instead of the root. (This link starts after the intro, and the natural 6th is heard at 1:06.)

Playing `i min6` instead of `i min7` doesn't qualify as a substitution because we're playing the same chord, just with different alterations.