TABLE OF CONTENT (Click to jump) |
Greetings, everyone! Rodrigo here again.
Today, we're exploring major & minor keys, where you'll learn all about the origins of every scale, mode, arpeggio, and chord we've talked about in past posts. I’ll also be answering some of the most common questions students make about this topic. If you're new here, this is the 11th post in a 15-part series where I've broken down everything a musician needs to know, from basic intervals to major and minor keys. You can easily catch up on the previous posts by clicking their titles below. And to my regular readers, thanks so much for your continued support! As always, I'll keep adding new posts every month, and I'll be updating the store section soon with some cool new stuff. If you haven't already, bookmark this blog and drop a comment below with any topics you'd like me to cover in the future.
Thank you all!
Rodrigo
List of posts:
Simples Intervals -> Compound Intervals -> Triads -> Drop-2 Chords -> Drop-3 Chords -> Shell Chords & Extensions -> Triads & Extensions -> Chord Melody -> Guitar Arpeggios -> Guitar Scales -> Major Keys -> Minor Keys -> Harmonic Minor Keys -> Melodic Minor Keys
WHAT'S THE "KEY" OF A SONG?
The ‘key’ of a song refers to its most stable note, the one that all other notes naturally want to resolve to.
Student: What? I don’t get it. Could you give me an example?
Rodrigo: Absolutely!
To answer your question, let me share the most important lesson you'll learn in your whole musical journey: music is all about tension and resolution. Let’s take the C major scale as an example since most people, whether musicians or not, are familiar with its notes. The notes in the C major scale are C, D, E, F, G, A, and B. In music theory, each note in the scale is referred to by its degree: 1st degree (C), 2nd degree (D), 3rd degree (E), 4th degree (F), 5th degree (G), 6th degree (A), 7th degree (B). If you continue up the scale after B, you arrive back at C, and the pattern of notes repeats.
C, D, E, F, G, A, B, C, D, E, F, G, A, B, and so on...
Now, if you're creating a melody or improvising a solo in the key of C, you’ll find that when you play the note C and let it ring out, it feels settled, like it doesn’t need to move anywhere. If you have a guitar, try playing a C major chord and singing a C note. Pay attention to the feeling it gives you (this is essential for developing your ears). If you have a piano, play the C major chord with your left hand and the C note with your right hand.
Next, let’s explore the sensation given by other notes. Try singing or playing the 2nd degree (D) over the same C major chord. You’ll notice that D wants to return and resolve to C.
Now, let’s try the 3rd degree (E). Sing or play E over the C major chord, and notice how E creates a pull, wanting to step down the scale to resolve to C.
Next, sing or play the 4th degree (F) and feel how it, too, seeks to resolve back to C.
Resolution can also happen upward! If you sing or play the 6th degree (A), you’ll notice that this note tends to move upward to resolve to C as well.
Rodrigo: Did you notice that when we finally arrive at C, it feels like the melody or musical phrase has come to a conclusion?
Student: Yes! I can hear that!
Rodrigo: That’s exactly what defines the key of a song, and it’s why nearly all songs—99.99% of them—end on their key center. If you’re trying to identify the key of a song and can’t rely on your knowledge of key signatures, a good rule of thumb is that the final note of the melody is usually the key. This also applies when learning a song by ear: listen for the last note of the melody and find it on your instrument. This happens because the end of a song is where the melody and all the tension created by it have to be resolved.
Student: But will that always work?
Rodrigo: Not 100% of the time. Sometimes, a composer can intentionally end a song on a different note to create tension or an unfinished feeling. But as I mentioned, in the vast majority of cases—99.99%—this principle holds true. It’s a solid foundation for developing your ear!
Student: Awesome! I think I get it now!
Rodrigo: There are lots of ways to figure out a song's key besides this, and each of the next topics will build on that. Make sure to pay attention to the end of each topic, as I'll highlight something important related to it.
MAJOR KEYS
The term 'major key' refers to all chords derived from the major scale, also called the natural major scale.
MAJOR SCALE FORMULA
Now that you know what a song's key is, the next step is to determine whether the key is major or minor. This depends on the third degree of the scale. Let's use the C major scale as an example (C, D, E, F, G, A, B) to break down the major scale formula and figure out the chords it generates.
The 12 notes in Western music are all separated by a semitone (or half-step):
C - Db - D - Eb - E - F - Gb - G - Ab - A - Bb - B - C
A semitone is the smallest distance between two notes. On your guitar, this means moving from one fret to the very next one on the same string. For example, if you play C on the 3rd fret of the A string, Db is on the 4th fret, D on the 5th, Eb on the 6th, and so on. Remember, two semitones equal one whole-tone (or whole-step), which means you would move two frets to cover a whole-tone. So, C and D are separated by a whole tone, just like D and E.
Now, let's look at the intervals between the notes of the C major scale:
C - whole tone - D - whole tone - E - semitone - F - whole tone - G - whole tone - A - whole tone - B - semitone - C.
The major scale formula is mostly made up of whole tones, with two exceptions: between the 3rd and 4th degrees, and between the 7th degree and the octave (where the scale starts repeating). These semitones occur because in the Western Music System there's no note between E and F, or between B and C.
So, the major scale formula is:
1st degree - wt - 2nd degree - wt - 3rd degree - st - 4th degree - wt - 5th degree - wt - 6th degree - wt - 7th degree - st - Octave.
st = semitone
wt = whole tone
What defines a major scale is the distance between the 1st and 3rd degrees. If they're separated by 2 whole-tones, it's a major scale. If there's 1 whole-tone and 1 semitone, it's a minor scale (which we'll cover next).
Before we move on, make sure you understand how to find the notes for any major scale. Try writing them down, then compare your results with the answers below. Just follow the scale formula starting from the key center.
CHART OF MAJOR SCALES |
P.S. If any of these terms are unclear, take a moment to revisit the posts I wrote on Intervals and the formation of Triads and 7th-chords.
P.S. 2 - You might have noticed that I used flats (b) for some keys and sharps (#) for others. As long as you got the correct answers, don't worry about it for now. You'll learn when to use each one when we get to the cycle of fourths and fifths.
Student: I’m following!
Rodrigo: Cool!
CHORDS FROM THE MAJOR KEYS (TRIADS)
Triads are the simplest form of chords, made up of three notes: the root (1st degree), third, and fifth. We’ve covered this before, but here’s a quick refresher:
Major triads are formed by the root, a major 3rd, and a perfect 5th (e.g., C major = C, E, G).
The root is the note that defines the chord's origin (C).
The major 3rd is 2 whole tones above the root (E).
The perfect 5th is 3 whole tones and 1 semitone from the root (G).
Minor triads consist of the root, a minor 3rd, and a perfect 5th (e.g., C minor = C, Eb, G).
The minor 3rd is 1 whole tone and 1 semitone from the root (Eb).
The perfect 5th is 3 whole tones and 1 semitone from the root (G).
Diminished triads are made up of the root, a minor 3rd, and a diminished 5th (e.g., C diminished = C, Eb, Gb).
The diminished 5th is 3 whole tones from the root (Gb).
That’s all you need for now! Back to the C major scale: C - whole tone - D - whole tone - E - semitone - F - whole tone - G - whole tone - A - whole tone - B - semitone - C.
Each of these notes will form a type of triad, and there's a simple method to find the notes for each one. To build a triad, start with the root note, skip the next note to find the 3rd, then skip another note to find the 5th. For example, to find the notes in the C triad, start with C (root), skip D to reach E (3rd), and skip F to reach G (5th). Once you’ve identified the notes, measure their distances from the root to determine the type of triad. Since E is 2 whole tones from C, it forms a major 3rd, and since G is 3 whole tones and 1 semitone from C, it forms a perfect 5th. Together, these form a major triad, so the first chord in the C major scale is C major.
Let's apply the same process to the second degree of the scale. Now, consider D as the root of the new triad. Skip the next note (E) to find F (3rd), then skip G to find A (5th). Measure the distances: F is 1 whole tone and 1 semitone from D, making it a minor 3rd, and A is 3 whole tones and 1 semitone from D, making it a perfect 5th. This forms a minor triad, meaning the second chord in the C major scale is D minor.
For the 3rd degree, it'll form E minor. E (root), G (minor third), B (perfect fifth):
For the 4th degree, it'll form F major. F (root), A (major third), C (perfect fifth):
For the 5th degree, it'll form G major. G (root), B (major third), D (perfect fifth):
For the 6th degree, it'll form A minor. A (root), C (minor third), E (perfect fifth):
For the 7th degree, it'll form B diminished. B (root), D (minor third), F (diminished fifth):
And by following this process for all seven degrees, we found the following triads:
C - Dm - Em- F - G - Am - Bdim
When referring to chords, we'll use the Roman Numerals system to simplify it, so we can make it into a formula. The triads in a harmonic minor key are represented as:
I - IIm - IIIm - IV - V - VIm - VIIdim
The good news is that this formula is universal and works for all keys. In any major key, the first chord will always be major, the second minor, the third minor, the fourth major, the fifth major, the sixth minor, and the seventh diminished. It’s important to memorize this formula, just as you did with the major scale.
Since we’ve already identified the notes for all 12 major scales, we can now apply this chord formula to find all the chords generated by each one. You’ll end up with the following results:
CHART OF MAJOR KEYS [TRIADS] |
CHORDS FROM THE MAJOR KEYS (7TH-CHORDS)
Seventh chords are like the triads we've been working on, but with an extra note added—the 7th—by skipping one more note after the 5th. But first, here's a quick review of the most important seventh chords you should know:
Major triad with a major 7th becomes a maj7 chord (e.g., Cmaj7= C, E, G, B).
The major seventh is 5 whole tones and 1 semitone from the root (B).
Major triad with a minor 7th becomes a dominant 7 chord (e.g., C7= C, E, G, Bb).
The minor seventh is 5 whole tones from the root (Bb).
Minor triad with a minor 7th becomes a min7 chord (e.g., Cm7 = C, Eb, G, Bb).
Diminished triad with a minor 7th becomes a min7(b5) chord (e.g., Cm7(b5) = C, Eb, Gb, Bb).
Since the process is just like what we did with triads, we'll move a bit quicker. We already have the triads, so all that's left is to find the 7th by skipping one more note after the 5th. Once you find it, measure the distance from the 7th to the root.
For the 1st degree, it'll form Cmaj7. C (root), E (major third), G (perfect fifth), B (major 7th):
For the 2nd degree, it'll form Dm7. D (root), F (minor third), A (perfect fifth), C (minor 7th):
For the 3rd degree, it'll form Em7. E (root), G (minor third), B (perfect fifth), D (minor 7th):
For the 4th degree, it'll form Fmaj7. F (root), A (major third), C (perfect fifth), E (major 7th):
For the 5th degree, it'll form G7. G (root), B (major third), D (perfect fifth), F (minor 7th):
For the 6th degree, it'll form Am7. A (root), C (minor third), E (perfect fifth), G (minor 7th):
For the 7th degree, it'll form Bm7(b5). B (root), D (minor third), F (diminished fifth), A (minor 7th):
And by following this process for all seven notes, we found the following 7th-chords:
Cmaj7 - Dm7 - Em7 - Fmaj7 - G7 - Am7 - Bm7(b5)
Which, in the Roman Numerals, will be:
Imaj7 - IIm7 - IIIm7 - IVmaj7 - V7 - VIm7 - VIIm7(b5)
And the same order of 7th-chords we'll be applied to all the other keys as you can check in the following chart. So far, you have to memorize three things: the major scale formula, the triads formula, and the 7th-chords formula.
CHART OF MAJOR KEYS [7TH-CHORDS] |
Student: Okay, I have these seven single notes, seven triads, and seven 7th chords. What should I do with them?
Rodrigo: These notes and chords are the building blocks for composing in the key of C major. You’ll use the single notes—C, D, E, F, G, A, and B—to create your melody, and the triads and 7th chords derived from these notes to make the chord progressions for your song. Of course, this is an example using the C major scale, you still have 11 more keys to explore.
Student: So, are these the only chords I can use? Just these seven triads and seven 7th-chords?
Rodrigo: Not exactly, but these are the essential chords that define the key. They're known as diatonic chords because they're all derived from the original scale. While you can add non-diatonic chords to have more options, you’ll need to return to the diatonic chords to maintain the sense of the key. Otherwise, the song might lose its tonal center and not make sense.
Further in this conversation, you'll learn about other categories of chords like secondary dominants, substitute V7 chords, IIm7-related chords, and modal interchange. These chords offer more options for your compositions but are commonly used to lead back to the diatonic chords.
Student: Got it! What about minor keys?
Rodrigo: Hold on, there’s one more thing. You can also add tensions—like 9ths, 11ths, and 13ths—to these chords to enrich your harmony!
CHORD EXTENSIONS (TENSIONS)
Since we used four notes of the scales to form the core of our 7th-chords, we can now add the remaining three notes from the scale to embellish the sound of each chord even more. These 'extra notes' will be referred to as tensions or extensions.
Student: So, can I use all seven notes to play any of these chords? What would be the difference if they all contain the same notes?
Rodrigo: That's actually an excellent question! First of all, as a guitarist, playing all seven notes simultaneously would be quite challenging, though there are exceptions. Secondly, once you've established the basic triad or 7th-chord, you don't need to include every tension at once—you can experiment with different combinations or even use just one. It all depends on what sounds good to your personal taste.
Moreover, as a rule of thumb, the notes that form the core of the chord are usually played in the lower register, while tensions are typically added in the higher register. This distinction between the lower and upper structure helps differentiate chords not just by the order of the notes but also by the unique sound they produce when tensions are added.
If you need to see examples of how to add tensions to chords, check my posts on Triads & Extensions or Shell Chords & Extensions.
Student: I'll check it out right now!
Just a quick review on tensions:
If the tension is 1 semitone above the root, we'll call it a minor 9th (b9)
If the tension is 1 whole tone above the root, we'll call it a major 9th (9)
If the tension is 1 whole tone and 1 semitone above the root, we'll call it an augmented 9th (#9)
If the tension is 2 whole tones and 1 semitone above the root, we'll call it a perfect 11th (11)
If the tension is 3 whole tones above the root, we'll call it an augmented 11th (#11)
If the tension is 4 whole tones above the root, we'll call it a minor 13th (b13)
If the tension is 4 whole tones and 1 semitone above the root, we'll call it a major 13th (13)
If you've already read the articles I mentioned earlier, you're familiar with the concept of avoided notes. But in case in haven't, here's another quick refresher:
Even though we'll find a different type of 9th, 11th, and 13th, to each chord of the key, it doesn't mean that all of them can be added to the chord since they might alter the chord's quality or function. As a rule of thumb, any tensions that's located 1 semitone above any chord-tone (notes that form the chord) is considered to be avoided. Which means that we can't let that note ring out simultaneously with the chord.
We consider the perfect 11th an avoided note for major, dominant, and augmented chords (C, C(#5), C(b5) Cmaj7, C7, Cmaj7(b5), Cmaj7(#5), C7(b5), C7(#5)) because it creates a dissonance with the major 3rd that can alter the character of the chord.
We consider the minor 13th an avoided note for major and minor chords (Cm, Cm7, Cm(maj7), and the major chords cited above) because it creates a dissonance with the perfect 5th that can alter the character of the chord.
We consider the minor 9th an avoided note for major, minor, diminished, and augmented chords too, because it creates a dissonance with the root that can alter the character of the chord.
The only exception to the two last rules above is the dominant chords (e.g., C7, C7(b5), C7(#5)), because its function is to create tension to then be resolved in a tonic-function chord. Then, minor 9th as well as the minor 13ths are welcome, but the perfect 11th remains avoided.
With that in mind, I'll apply the same approach to all seven degrees of the scale and give you the results directly. All you need to do is calculate the interval between each (ext.) tension and the root note.
For the 1st degree, the tensions are the major 9th, perfect 11th, and major 13th. However, since the perfect 11th is an avoided note in major chords, you can only add the major 9th and major 13th. The possible chords for the 1st degree include C, Cmaj7, C(9), Cmaj7(9), C(13), Cmaj7(13), C(9,13), and Cmaj7(9,13). I've used both triads and 7th chords in these examples.
For the 2nd degree, the tensions are the major 9th, perfect 11th, and major 13th. Then, the possible chords for the 2nd degree include D, Dm7, D(9), Dm7(9), Dm(11), Dm7(11), Dm(13), Dm7(13), Dm(9,11), Dm7(9,13), Dm(11,13), Dm7(11,13), Dm(9,11,13), and Dm7(9,11,13). All the tensions are available, no avoided notes.
For the 3rd degree, the tensions are the minor 9th, perfect 11th, and minor 13th. However, since the minor 9th and the minor 13th are avoided notes for minor chords, you can only add the perfect 11th.Then, the possible chords for the 3rd degree include E, Em7, Em(11), and Em7(11).
For the 4th degree, the tensions are the major 9th, augmented 11th, and major 13th. Then, the possible chords for the 4th degree include F, Fmaj7, F(9), Fmaj7(9), F(#11), Fmaj7(#11), F(13), Fmaj7(13), F(9,#11), Fmaj7(9,#11), F(9,13), Fmaj7(#11,13), F(9,#11,13), and Fmaj7(9,#11,13). All the tensions are available, no avoided notes.
For the 5th degree, the tensions are the major 9th, perfect 11th, and major 13th. However, since the perfect 11th is an avoided note in dominant chords, you can only add the major 9th and major 13th. The possible chords for the 5th degree include, G, G7, G(9), G7(9), G(13), G7(13), G(9,13), and G7(9,13).
For the 6th degree, the tensions are the major 9th, perfect 11th, and minor 13th. However, since the minor 13th is an avoided note in minor chords, you can only add the major 9th and perfect 11th. The possible chords for the 6th degree include Am, Am7, Am(9), Am7(9), Am(11), Am7(11), Am(9,11), and Am7(9,11).
For the 7th degree, the tensions are the minor 9th, perfect 11th, and minor 13th. However, since the minor 9th is an avoided note for diminished chords, you can only add the perfect 11th and the minor 13th (yes, the minor 13 is available for diminished and half-diminished chords). The possible chords for the 7th degree include Bdim, Bm7(b5), Bdim(11), Bm7(b5)add11, Bdim(b13), Bm7(b5)addb13, Bdim(11,b13), and Bm7(b5)add11,b13.
Student: I have a question about improvisation, which is also related to the previous post about scales.
Rodrigo: Sure! Go ahead.
Student: You mentioned several scales and modes that can be used for improvisation over different chords. For example, I remember reading that for any maj7 chord, I could use the Ionian mode, Lydian mode, or Lydian #2. Each of these modes adds different tensions to the maj7 chord, so I’m wondering—depending on the context, is there a 'better' scale or mode to use?
Rodrigo: The reason all these modes work is that, in modern improvisation— and by 'modern' I mean since the era of Charlie Parker—we approach each chord individually, rather than viewing it as part of a specific key. You could call it 'modal improvisation,' but the main idea is that if the scale or mode contains the chord tones of the given chord, it will work!
THE CYCLE OF FOURTHS & FIFTHS
I'm writing this section because a lot of students ask me about the cycle of fourths and fifths and what they're used for. So, here’s a quick and straightforward answer: the cycles of fourths and fifths are essentially ways to organize the different major and minor keys based on the number of accidentals (flats (b) and sharps (#)) they contain.
If you compare the image below, which shows the cycle of fourths, to the chart of major scales, you'll see that the C major scale has no flats, F major has 1 flat, Bb major has 2 flats, Eb major has 3 flats, and so on—just follow the direction of the arrows.
Student: And why is it called the cycle of fourths?
Rodrigo: It’s called that because the interval between the root of each key is a perfect fourth. From C to F is a perfect 4th, from F to Bb is a perfect 4th, from Bb to Eb is a perfect 4th, and so on. The term "cycle" comes from the fact that if you keep following this sequence of fourths, you eventually circle back to C.
Student: What about its application?
Rodrigo: Honestly, there isn’t much.
Student: No application? What do you mean?
Rodrigo: Exactly that! You can use it to memorize how many accidentals are in each key, and it might help with remembering the chords too. But in terms of actually applying it to a song, there’s not much to it.
Student: Why didn’t you list the number of flats for the keys after Gb in the image?
Rodrigo: Good question! There’s a reason for that. Technically, I could write all the keys, scales, and chords using only flats. But after Gb, we’d have so many flats—and eventually double flats (like Dbb, Ebb, etc.)—that it’s easier to switch to sharps (#) instead.
Student: Oh! So that’s when we use the cycle of fifths?
Rodrigo: Exactly! The cycle of fifths is just like the cycle of fourths, but in reverse. From C to G is a perfect 5th, from G to D is a perfect 5th, from D to A is a perfect 5th, and so on. This happens because perfect 4ths and perfect 5ths are complementary intervals. If you've been following along from the start, you probably already know this.
Student: Oh, wait! Earlier, I noticed the charts were in a strange order—is that because of the cycles?
Rodrigo: That’s right! All the charts are organized according to the cycle of fourths. But after Gb, I started using sharps instead of flats for the reasons I just explained.
To sum it all up: when writing in the keys of F, Bb, Eb, Ab, Db, and Gb, we use flats (b). When writing in the keys of G, D, A, E, and B, we use sharps (#).
Student: Now it all makes sense!
KEY SIGNATURES
The term "key signature" refers to the collection of accidentals (flats and sharps) indicated at the beginning of a piece of music, placed between the clef and the time signature on a lead sheet. As we discussed earlier, each major key is defined by a specific number of accidentals, which can be either flats (♭) or sharps (♯). By matching the accidentals in the key signature with those in each major scale, we can easily identify the key of a piece.
Here’s a quick reference:
No flats or sharps: C major
1 flat: F major
2 flats: B♭ major
3 flats: E♭ major
4 flats: A♭ major
5 flats: D♭ major
6 flats: G♭ major
1 sharp: G major
2 sharps: D major
3 sharps: A major
4 sharps: E major
5 sharps: B major
READ! |
P.S. An important concept called "Relative Keys" will be discussed in the next post when we explore minor keys. In brief, each key signature corresponds to both a major key and a minor key that share the same notes, accidentals, and chords. To accurately determine the key, it's helpful to check the final note of the melody and see if it aligns with the key signature. If it does, great! If not, stay tuned for the next post to learn more!
Student: I just remembered—didn’t you say you wanted to mention something about each topic?
Rodrigo: Yes, you’re right! I wanted to emphasize that there are many ways to identify the key of a song, whether you have the sheet music or are learning by ear. As I mentioned before, the most reliable method is to pay attention to where the melody resolves, especially at the end of the song, as the notes usually gravitate back to the key center. If you have access to the key signature, it becomes much easier since it narrows down the possibilities to one major or one minor key. Additionally, as you become more familiar with the chords that define each key, it will guide you in identifying the correct key. For example, if a song includes a Bbmaj7 chord, you know it’s not in the key of C or G major. Certain chords are unique to specific keys, and the more you practice, the faster you’ll be able to recognize them!
HOW TO PRACTICE MAJOR KEYS?
The whole point of talking about major and minor keys is to pull together everything you've learned from the previous posts. If this is your first time here, you can still use what you learned in this post to start writing songs, building chord progressions, creating melodies, and even making your own solos. But I highly recommend checking out the earlier posts too—they're packed with different ways to play the chords and scales I mentioned here, and they'll help you get comfortable playing all over the fretboard.
We’re not done with this topic yet! In the next few posts, we’ll cover minor scales, Greek modes, harmonic functions, harmonic rhythm, and some of the most common chord progressions. So, stick around, bookmark this blog, and I’ll catch you later!
All my best,
Rodrigo Moreira
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