Diatonic, Extended, Chromatic, and Borrowed Chords

My previous blog post was about modes and their equivalent in Indian music. If you haven't checked that out yet, it might help set the stage for today, which is all about harmony derived from the melody discussed earlier.

A diatonic triad is just a three-note chord. Your basic major and minor chords are triads. Pretty straightforward. Diatonic simply means from within the scale.

For beginners, it's a question that comes up often: if you're playing all six strings, let's say in an E major chord on guitar, how's it three notes? Well, some of those notes are repeating.

Chords come out of scales - that's an easy way to think about them. Maybe towards the later stages one can argue otherwise, but that is like super advanced stuff. For now, as a beginner, you could live a nice, happy life accepting the fact that chords are derived from scales.

One of the layman's ways of talking about it would be to start, skip, and pick!

So in the case of C major scale (and not the chromatic scale), simply start from C, skip D, pick E, then skip F and pick G. That's right there: C-E-G, a three-note chord.

That's you harmonizing in thirds like a gangsta. Don't be thrown off by that buzz phrase; harmonising basically means to stack up the notes, and 3rds is a reference from Intervals (something you should know if you're reading this). Triads within the C major scale are given below:

Root	Notes	Chord Type
C	C – E – G	Major
D	D – F – A	Minor
E	E – G – B	Minor
F	F – A – C	Major
G	G – B – D	Major
A	A – C – E	Minor
B	B – D – F	Diminished

Why are some major, others minor, and one diminished?

Comes down to the spacing between the notes, the major scale has a built-in pattern (you’ve probably heard this before):

Whole – Whole – Half – Whole – Whole – Whole – Half

(W W H W W W H)

That pattern messes with the “thirds” depending on where you start. Some thirds end up a minor third apart (3 semitones), others are major thirds (4 semitones). And when both intervals shrink, as in the case of B D F — you get a diminished triad.

So yeah, even though we’re simply stacking by skipping notes, the quality of the chord (major, minor, diminished) is baked into the scale itself.

Keep stacking up notes, and soon enough, you'll have landed in the territory of the extended chords. There's a quick stop we ought to make first.

Quadads are four-note chords. The most common ones you'll run into are seventh chords. For example, if you take that same C major triad and stack another third on top, you get B. That gives you C-E-G-B, which is a C major seventh chord. That’s a Quadad.

Needless to say, there are other chords too which fall under this category, for eg, Cadd9 is one.

Yet, primarily 7th chords dominate the category as they have a wide use case. They are often used in mainstream music. Also, there are about 6-7 categories of 7th chords. Among these, there are three essential types: major seventh, minor seventh, and dominant seventh. If you’re playing or writing anything in pop, blues, R&B, or jazz, you’ll find these all over the place.

Each has a distinct feel. Major sevenths are smooth and resolved. Minor sevenths sound a bit moodier. Dominant sevenths carry tension, like a sentence waiting for the final word.

Right beyond the 7th, the extended chord theory comes into play, a recap before that...

You already know 1-3-5 is a triad. Add the seventh, and now you’ve got 1-3-5-7. That’s a seventh chord. To keep extending, you keep adding thirds.

After 7, the next third is the 9. Now, you might ask, how is there a ninth note in a seven-note scale? After the seventh, you cycle back to the octave and keep counting. The 9 is really the 2, one octave higher. In the key of C, that’s D. The 11 is F. The 13 is A.

And that’s the end of the road.

Why don’t we have 15ths or 17ths? Because by the time you hit the 13th, you’ve already used every note in the scale. Extensions loop around. You’re adding color to the chord using scale tones from a higher octave.

When/How Do You Actually Use Extended Chords?

Here's an Extended Chord Theory rulebook to fire up your harmony engine.

• Built by stacking thirds

  Every extension comes from stacking thirds on top of your basic triad. Triad is 1–3–5. Add another third and you get 7. Another third? That’s 9. Then 11. Then 13. That’s it. No 15ths, no 17ths. You’ve already cycled through the scale.

• Extensions are upper-scale degrees reused

  The 9th is the same as the 2nd. The 11th is the same as the 4th. The 13th is the same as the 6th. They’re just played an octave up, so they don’t clash as badly with the root or 3rd.

• 7th chord first, then extensions

  No skipping. You don’t go from a major triad to a 13th chord. The 13th includes everything: the 7th, the 9th, the 11th — it’s a package deal. You can leave stuff out when voicing it, but theoretically, they’re all in there.

• You can’t have a 9 without a 7

  A chord that says C9 implies it's C–E–G–Bb–D. Not just C–E–G–D. If there's no 7, it's technically an “add9.” Same with 11 and 13. Extensions need a 7 to be extensions — otherwise they're "add" chords.

• Add chords are not extended chords

  Cadd9 is not C9. Add chords skip the 7th. That gives a different feel — more open, less jazzy, often pop.

• Major vs minor vs dominant defines the 7th

  • Major 7th = natural 7

  • Minor 7th = flat 7

  • Dominant 7th = major triad + flat 7 (yes, this is its own thing)

  
  

• The extensions follow the mode of the chord

  • Major 7 chords use major 9, natural 11, and major 13

  • Dominant 7 chords often use flat 7, major 9, natural or sharp 11, and major 13

  • Minor 7 chords take flat 3, flat 7, and usually natural 9, natural 11, and flat 13

  
  

• Don’t stack all the notes in real-world voicings

  In practice, people drop the 5th, double the root, or leave out the 11th. It’s not cheating — it’s survival. Especially on guitar. Keep what matters: 3rd, 7th, and the extension you want to highlight.

• Altered extensions come from altered scales

  Flat 9, sharp 9, sharp 11, flat 13 — They usually come from specific modes like the altered scale (7th mode of melodic minor) or harmonic minor contexts. They’re not random.

• Extensions don’t change the root function

  A C13 is still C. It still resolves like C. You're not reharmonizing — you're decorating.

  
  

• More notes = more tension, not always more clarity

  Just because you can build a 13th chord doesn’t mean it fits everywhere. Use tension when you want complexity. Go simpler when you want space. Listeners don’t always care how many notes you stack — they feel the mood.
  

Well, one biggie you should pick out would be the difference between the extended chords and the added chords.

These regulations need to be grasped while keeping in mind that some of the best musicians don't know the names of the chords they are playing, often.

How to grip so many notes as a guitar player?

In fact, you usually can’t. Your hand can only stretch so far. So what do we do? We simplify.

You keep the core character of the chord. That usually means keeping the third and seventh and adding the extension you want.

The root is often played by the bassist. The fifth is sometimes dropped altogether unless it’s altered. The idea is to get the flavor without needing ten fingers and a second neck.

The flavour... Extended chords are lush because they hold tension. They stretch your ears without snapping the rubber band. But tension’s a social construct, musically speaking. Jazz folks hear a major 7th as “home.”

Rock folks hear it as “what the hell is that?” (Okay, subjective).

Plug in a Cmaj13 through a fuzz pedal and you’ve made a mistake — no matter how technically “correct” the chord is. Because distortion already fills so much sonic space, throwing too many notes in is the same as stuffing five fillings into one momo. You end up with a hot mess.

Jazz is quite accommodating. It is the home ground for extended chords, musicians often play only the extensions, leaving out the root. Also, distortion type dense sound effects aren't part of the genre

On to the Chromatic Chords

Whereas extended chords were about stacking up tones on top of the given triad, Chromatic chords have to do with the very triad modification.

In the cliché key of C major, if a D major chord suddenly pops up, that’s a chromatic chord, breaking out of the diatonic palette for a moment to push the harmony forward.

Another radically different perspective is to consider the scale to be C Lydian, in which case D major would be a perfectly diatonic chord. It's debatable what perspective to go for!

I guess it depends on the crowd you're hanging out with...

Chromatic chords feature one or more non-diatonic (outside the scale) notes, and Bollywood music is all about it.

Lately, I’ve been working through a playlist of nearly eighty Bollywood songs, mostly because I’m getting my chops back in shape to play live again with a Bollywood-style band.

I’d highly recommend digging into the music of Shankar-Ehsaan-Loy. With Ehsaan Noorani as a core part of the trio, you’ve got a guitarist fluent in jazz, blues, and rock, bringing in those western chops, but adapting them beautifully to fit the cinematic and melodic demands of Bollywood.

Their discography is a perfect crash course. Needless to say, Chromatic chords are everywhere, or if you'd like to think the other way around, it's mostly modal music.

Out of the monstrous playlist I came across only two tracks using extended chords (Jazz-style grips). Main Kya Karoon (by Pritam) from the movie Barfi and Khwabon Ke Parindey (by Shankar-Ehsaan-Loy) from the movie ZNMD.

The rest of the tracks were diatonically quite contained within the first six modes of the major scale. Worth mentioning though, regional grooves were often featured. The rhythm section for these tracks was rarely ever only drums.

Several rhythmic elements were bundled to create a strong groove and thus when starting out, guitarists often struggle justifying these dense grooves with 8th note strumming.

When I said “six modes” earlier, I meant it. That wasn’t a slip. I intentionally left out Locrian.

Locrian is the weird cousin nobody knows what to do with. It shows up at the family reunion, brings something confusing to the table, and leaves early. And in most practical music, whether it’s Bollywood, pop, rock, or even jazz, it’s barely used.

There’s a whole other direction we haven’t really zoomed in on yet. And that’s dyads.

If triads are three-note chords, dyads are the stripped-down version: just two notes.

And rock and metal is where they shine!

Let’s call out the most famous dyad of all time — the power chord:

Root + Fifth (e.g. E and B)

It’s not technically a major or minor chord. Why? Because there's no third, which is the note that usually decides if a chord is happy (major) or sad (minor). This ambiguity is exactly what makes power chords perfect for distortion-heavy music. They don't clash with the overtone chaos that comes with cranking up the gain.

In fact, in metal and hard rock, the more harmonically "neutral" your chords are, the more room there is for aggression.

And here's the fun part—while they’re harmonically simple, dyads can still hint at modal flavor, chromatic tension, and even complex harmony just by what they're paired with.

You might not be "voicing" a C7♯9 on the fretboard, but the movement of dyads, or their placement against a bassline, can imply way more than what’s physically being played.

Let’s zoom out for a second.

• Jazz is where you see full-blown extended chords — 9ths, 11ths, 13ths, often stacked and altered for maximum complexity.

• Pop sometimes dips into 7ths or add9s for color, but generally keeps the harmony clean and digestible.

• Blues lives on dominant 7ths but also uses dyads in lead/rhythm interplay.

  
  

• Metal and Rock lean heavily on dyads, not out of limitation but by design—especially when drop tunings, fast riffs, and distorted tones come into play.

  
  

• Prog, fusion, and cinematic scores go all over the place—sometimes dyadic and riff-driven, sometimes full-on orchestral extended chords.

  
  

• Bollywood utilizes chromatic chords often due to heavy modal interplay.

Say you're hanging out in C major. Everything's happy, sunlit, diatonic.

Then suddenly — bam! You drop in an A♭ major chord. It’s not in C major. It shouldn't work. But it does. That’s a borrowed chord. You just reached into the parallel minor (C minor in this case) and yanked out something darker.

The term for this is modal mixture: borrowing chords from the parallel mode to add emotional depth or surprise.

Where most borrowed chords in a major key come from:

Borrowed From	Examples in C Major	Emotional Effect
C minor	A♭, E♭, Ddim	Darker, dramatic
C Phrygian	D♭, B♭m	Cinematic, tense
C Dorian	A minor with ♯6 (A–C–F♯)	Quirky, jazzy

Radiohead is a band that comes to mind here.

Chromatic chords push against diatonic expectations, while borrowed chords bend them as two notes from the triad are being altered, as compared to one note being altered in chromatic chords discussed earlier.

If you struggled with the last sentence, head back to the previous post about modes.

Say Bye!

Anubhav Kulshreshtha

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