Recognising Keys by Chord Sequences

Good question with no simple answer at all. Power chords are neither major nor minor. They do exist at interval spacings apart from one another however. If we look at an example and follow through the various options it gives.

Power Chord progression:

| G5 | C5 | E5 | G5 | A5 | B5 | C5 | D5 | G5 |

All chords are power chords.

If we space them out alphabetically:

A - - B - C - - D - - E - - x - - G - - A

  • A → B is a whole tone
  • B → C is a semitone
  • C → D is a whole tone
  • D → E is a whole tone
  • G → A is a whole tone

Using Justin’s guidance from the lesson:

We have four instances of two chords a full tone apart. We have one instance of two chords a semitone apart. All possible options are shown in this grid.

Given there are four potential paths to consider if we start with the chords that are a whole tone apart, it makes sense to limit our options. We will work from the B → C chords being a semitone apart and fix those two chords in one of two possible ways. We can them see what results.

First, we will make the B and C chords fixed as the iii minor and the IV major chords. It must necessarily follow that G is I major, A is ii minor, D is V major and E is vi minor. We do not have a vii diminished chord. These chords are shown in blue on the grid.

The power chord progression above would become:


Second, we will make the B and C chords fixed as the vii diminished and the I major chords. It must necessarily follow that D is ii minor, E is iii minor, G is V major and A is vi minor. There is no IV major. These are shown in yellow on the grid.

The power chord progression above would become:


It may now be a simple case of playing these progressions using the full range of chords and listening carefully to see which sounds best.

I hope that helps.

Foot note:

Many genres that are very power chord centric will have progressions that are non-diatonic and use a range of power chords that are not in the key of the song. Such power chord progressions do then become very tricky to analyse without greater musical context, especially harmonic context such as the vocal melody notes etc. Many lead guitar solos will switch around minor and major pentatonic scales that match the underlying power chord when there is no one obvious key the chords all fit within.


What a really complete and detail answer, Richard. Many thanks. I’ll bookmark it because it will be very handy on my Music Theory journey

Many thanks :blush:

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Hi all

Louie, Louie by The Kingsmen has the chords A, D, Em, D. I figured this was the key of D, with chord progression V → I → II → I.

But on verifying this with Google, it says it’s “A Mixolydian”. Can anyone shed some light on this?

Are both correct? Or have I stumbled upon some advanced theory and should ignore this song?


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The way I understand modes is that they are an offset of another scale. The same notes but you make the root note or start the scale in a different position.

You have worked out that the song fits the D scale. A mixolydian is the 5th degree of the D scale D - E - F - G - A (1,2,3,4,5), which makes A the root or home chord. It uses the chords from the key of D, but starts and ends on A :exploding_head:…. Here endeth my poor knowledge :slightly_smiling_face:

Mixolydian the sound of rock: The Mixolydian Mode | THE SOUND OF ROCK - YouTube

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Hey mate,

When you play the chord progression of Louie Louise, what chord feels like ‘home’ - the one all the other chords seem to move to? For me its definitely A. So the key is A. But what sort of A?
Looking at the other chords, the Em is the one that seems ‘out of place’ diatonically, as E major is the 5 chord in the key of A major. This Em is ‘borrowed’ from the parallel key of Am. Check your circle of fifths and you’ll see its the 5 chord of Am.
So you could say its in A major with a borrowed chord from the parallel key.

You could also look at it by writing out the notes of all the chords in the progression. When you do, you’ll find all the notes of the A major scale, except the 7th note, which, instead of a G#, its a G. So its a b7.
A major scale with a b7 is the mixolydian mode, so A mixolydian.

Cheers, Shane

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Hello @tastysandwich and welcome to the community.

That is a reasonable first analysis.
Note - were that to be the case, the Em would be denoted as ii (lower case for minor and diminished chords).

However, because the chord A is the resolution chord, the home base, it is the tonic here and needs to inform the analysis.

A major scale, scale degrees and its chords:
1, 2, 3, 4, 5, 6, 7 → A, B, C#, D, E, F#, G# → A, Bm, C#m, D, E, F#m, G#dim
If you know about chord construction and how stacking thirds from the major scale builds the triads you will know where those chords come from and their constituent notes.
A → A, C#, E
Bm → B, D, F#
C#m, C#, E, G#
D → D, F#, A
E → E, G#, B
F#m → F#, A, C#
G#dim → G#, B, F#

What we perform this process in reverse from the given chords of the progression in Louie Louie?

A → A, C#, E
D → D, F#, A
Em → E, G, B

We can fill chords in three of the seven spaces and due to the Em chord need to change G# for G (the 7th scale degree becomes b7th - shown in bold).

1, 2, 3, 4, 5, 6, b7 ← A, B, C#, D, E, F#, G ← A, --, --, D, Em, --, –

By stacking thirds we could compelte the remaining chords if wanted.

1, 2, 3, 4, 5, 6, b7 ← A, B, C#, D, E, F#, G ← A, Bm, C#dim, D, Em, F#m, G

Bm → B, D, F# (as above)
C#dim → C#, E, G
F#m → F#, A, C# (as above)
G → G, B, D

The three chords can be seen as coming from a scale that is not A major. They derive from a scale whose root is A but whose 7th scale degree is the note G, a b7. That scale is A mixolydian. The progression is a I, IV, v, IV in A mixolydian.

@sclay also mentions that the Em could be viewed as a borrowed chord. That is also a valid view though in terms of any melodic analysis and any thoughts of playing lead lines over the progression, it too would point towards an emphasis on the b7 note G.

If and when you do work through more theory and have covered Justin’s lessons on modes, the circle of fifths etc you may find useful complementary and supplementary reading here:

That is often how they are taught - “it’s the major scale but starting on a different note”. I think that particular approach to teaching and learning modes does a disservice to being able to understand, hear and use modes for musical creativity. Modes are scales (with unique intervals and chords) in their own right. Hence I wrote such a large topic in seven parts.

I hope that helps.

Cheers :smiley:

| Richard_close2u | JustinGuitar Official Guide, Approved Teacher & Moderator

I did wonder, why nobody else was mentioning it and taught each mode as a same as xyz with a flat 7th or whatever. I thought I was a genius when I realised the A minor scale was the C major scale just starting from a different place :roll_eyes::rofl:

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I joined a theory group on Facebook recently, and all they ever seem to do is argue back and forth about what modes are. Wont be a member much longer methinks.
Like @Richard_close2u explained, modes are essentially scales, derived the major scale, as is everything else.
That " major scale starting on a different note" view is a pattern recognition thing, and has little musical value in my view.

Grateful I was taught the right way by Justin, and knowlegeable folk like Richard and others here.
Proof again that all the good sauce is right here at Justin Guitar!

Cheers, Shane


Great summary Shane.
It is a short cut route to trying to teach people who know one or more major scale patterns that they then must, necessarily and logically, know all of the scale patterns for every mode of the major scale. It is kind of true in terms of finger placement. But with huge caveats and drawbacks. Muscle memory and familiarity of starting on and ending on certain notes and emphasising certain notes can make a player subconsciously get pulled back to major scale playing, away from modal playing. The intervals and the colour notes are all different in modal play.


So many reactions on this topic, but it looks like nobody has the same problem as I have.
I have no problem with the theory and 10/10 with the quiz, but I can’t imagine that I will ever in my life hear two majors chords one tone apart or two minors or even harder: a minor, a semitone followed by a minor.
So I can say, my brain functions good, but my ears don’t and this makes me insecure at this moment!
When I listen too music I hear all the details, but not the structure. The blues progression is the only progression I recognize. Even when I know I’m listening to an 1, 5, 6, 4 progression I don’t recognize it.
I can make my own progressions (often using power chords) by playing what sounds good to me. And I love music and playing guitar very, very much. Say 1 hour a day. Active for almost 4 years now.
Last thing to say: I don’t really like learning songs, I love much more making my own melodies, riffs, etc.
People with the same experience and “fear” here? Any advice? I guess ear training and repeating the progressions a lot?

Forgive me for selective editing but I think it will highlight the response I feel compelled to give.

I have to start with my mantra: learn songs, learn songs, learn songs.
The reasons I keep repeating that are manifold.
The most relevant here is that it is ear training.
If you learn many, many songs you are training your ear to hear, to know, to be familiar with, to recognise and anticipate chord progressions and fundamental patterns that occur across all musical genres. From pop to country to rock to indie to folk - the same recurring harmonic movements will be found. Whether that be a V (or V7) chord resolving to a tonic chord, or an ascending minor ii chord to minor ii chord to a IV chord or a ubiquitous I, vi, IV, V (think doo-wop and soul ballads) or the famous Axis of Awesome 4-chord progression I, IV, vi, V. Or it could simply be that you begin to recognise a very familiar move such as D → Dsus4 → D - Dsus2 → D.

Learn songs and you will learn to recognise these movements. And you will begin to recognise, or at least be able to figure out fairly quickly, two major chords one tone aprt, two minor chords one tone apart etc.


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Thank you Richard for your reaction! I guess I have to start learning songs now! :grinning: About a week ago I started ear training with chords so I hope to improve that way. It starts with chords and then uses real music. I think this will help me, and to be honest, I’m really enjoying it. It’s a quiz you play and I’m not bad at all at the easy and medium levels!

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Exams man that thing :woozy_face::woozy_face::confounded::confounded::cold_sweat::cold_sweat::cold_sweat:, it was deep :disappointed_relieved::disappointed_relieved::disappointed_relieved::disappointed_relieved:

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Super cool lesson. I practiced this with a bunch of songs, and one that tripped me up for a second was the song Too Much Of A Good Thing by The Sons. I noticed there was a C and aa D, and said, “Aha! Two major chords a tone apart - must be G major!” However, I noticed F major was prominently featured in the song as well - how can it be G major then? When I looked at all the chords again, I noticed the D major that originally tipped me off only appears in one tiny section, so I pretended it wasn’t there and viola, we have C major. Am I correct in saying that this song is indeed in C major, and that the D major is a key change that sort of outros the chorus?

@ChrisAbeGuitar You are correct all the chords except the D are in the key of C the D is the 5 of 5.
Meaning the 5th of C is G and the 5th of G is D
The tip for the key of C is the F and G are major.

@stitch The 5 of 5 makes a lot of sense, hoping to learn a little more about that thinking in the coming lessons.

I am having a very difficult time identifying chord progression patterns in songs and what chords are being played. i have no problem with everything else, but i my ear cant seem to know which chords are which, if it’s ascending or descending, and sometimes i can’t even tell if a chord is a minor or major chord due to multiple instruments being played. i have practiced, written, and memorized everything justin has covered up to this lesson, but with this i really can’t get my head around this. Someone please help me on what to do, i love playing guitar and have been for playing for 3 years.

I have tidied up the posts about Too Much Of A Good Thing to remove the typos and responses to them.

Here is a slightly different analysis.
The intro and verse simply bounces back and forward between C and Em but it feels tense, unresolved, looping around with no place to settle.
Then, when the chorus arrives - do you hear how satisfying that G chord is? They have arrived at the tonic. The key of G but until the chorus the tonic chord has been avoided with a two-chord vamp that tricks us. The solo and bridge use F and in the key of G that is a bVII chord, a commonly borrowed chord.

Robbie, you can train your ear and Justin has Ear Training courses to help develop this essential skill.

one of the most important things you can do is familiarise your ear and your expectations of chord movements is by following my mantra - learn songs, learn songs, learn songs. By learning songs you are exposing your ears to many, many ways that chords are used in combination. The combinations are limitless but there are a handful of very commonly used patterns that you will encounter across all genres - so learn and and all songs whether it is your taste or not.

thank you for the advice.