Triad Chord Analysis

Let's use our knowledge to learn how we can sort out the names of any chord we encounter!

View the full lesson at Triad Chord Analysis | JustinGuitar

Just in case you guys missed this very useful tip (I don’t think it was in the video, but written below the Triad Chord Theory Video.) Copied from the page below:

“My student ReyGuitar (username) suggested a fun way to remember them! The note B is on its own with a # on both 3 and 5. The chords of the DEA (think Drug Enforcement Agency) have a # on the 3rd, and the rest are all naturals! Good one, Rey! :)”

That tip, combined with Fat Cat Gets Drunk At Every Bar mnemonic FCGDAEB, you can figure out which notes on the flat or sharp keys aren’t natural without needing the whole chart of Keys.

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Hey great lesson as always! But I have a BURNING question. You see, I don’t know the major scale notes of sharp scales like A# or D#. I triple-checked the Mr. Cato’s formula and the comments there but I didn’t come across any answers that made sense. I’m 100% sure that FCGDAEB “trick” (although absolutely amazing!) doesn’t cover sharp major scales besides the exceptions of F# and C#. (Justin talks about these in the lesson)

But again, what about other sharp major scales? Like E# major, G# major or D# major for example? Is there a formula or any way to know what the notes of those scales are?

If somebody could help me out with this I’d REALLY appreciate it! As I’m almost 100% confident with all the theory I learned in this amazing course so far. But I couldn’t get my head wrapped around this one.

Thanks a lot!

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Hi my suggestion would be to go with flats rather than sharps, it’s way easier as you can use Mr Kato’s trick and you know how many flats each scale have thanks to the trick. After all they are equivalent tonal wise with sharps :slight_smile:


Thanks man, I didn’t think that they were enharmonic equivalents you’re right!


It is always the simplest answers are the least obvious ones! :grinning_face_with_smiling_eyes:


True dat haha

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I’m confused about A diminished. The formula is 1 b3 b5 then why are the notes A C Eb? Shouldn’t C be flat as well?

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The formula for A major is 1 3 5, or A C# E. So, A dim 1 b3 b5 is A C Eb.


Thanks, I was thinking it was C

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The exercise says to recognize the chord start with the lowest of the three notes. The notes are E, G and B flat. It says E is the lowest note so start there. How do we know that E is lower than B flat? Thank you.

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Hi Mike,
The notes E, G and B make up the E triad chord. E is the root note of that chord. Even if the B-flat note was lower than the E note in the example it would still be an E chord, because it contains the notes E G and B.

Here are the notes I made after watching Justin’s lesson. Hopefully they don’t confuse you even more!

Determining a Triad from its Notes

The most common triad letter groups are ACE, BDF, CEG, DFA, EGB, FAC & GBD. In the real world, the notes you have may not be in the order 1-3-5 (inverted or jumbled triads), so you need to know the letter groups if you want to determine a triad from its notes. Work out which one of the above groups the three notes belong to and put the notes in the correct order (1-3-5). Then use the appropriate major scale to determine whether the chord is a major, minor, augmented or diminished triad.

For example:

You see the notes E, G, and Bb in a chord, and you want to know the name of that chord. Start by comparing the notes to the major scale of the lowest note. You have EGB so it’s the E major scale (E F# G# A B C# D# E).

  • · E is the root note.
  • · The G is a 3rd of some kind. In the E major scale, the 3rd note is G#. In our chord we have G, so the note has been flattened, making it a b 3.
  • · The last note is the 5th. In the E major scale, it’d be B, but as it’s a Bb , it’s a b 5.

You’ve got 1, b 3 and b 5, which is a diminished chord (E dim).


Hello @StratManMike and welcome to the community.

You ask …

I’m not being awkward here … just trying to help you see the wood and the trees.
You know that E is the lowest note because the question / example states that it is. You do not need to second guess anything here.
I hope that helps.
Cheers :smiley:
| Richard_close2u | JustinGuitar Official Guide, Approved Teacher & Moderator

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But how would I know that in the real world when I’m trying to determine the chord without being told it in a lesson? I appreciate your somewhat glib response but TBH it doesn’t really help.

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Hi jacksprat,

That’s a very helpful tip. Thank you.

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In the real world, you should know which notes are in the chord, but how you do this depends on the circumstances.

If you are analysing a chord you know the fingering for, then you know which the notes are based on where the chord is fretted (or not) on each string. The note on the lowest string played will be the lowest note in the chord.

That doesn’t necessarily mean it is the root note. You have to look at all the notes in a chord to understand what the chord is and, therefore, what the root note is.

If you are transcribing, then you will be trying to listen and understand which notes are in it (perhaps by finding those notes on the guitar or a piano). In that case your ears should tell you which is the lowest note.

Again, that might not be the root note.




Have you encountered any slash chords already? They are like this in the sense that their lowest note is not the root note. Take the open C chord for example. If you fret the G note on the 6th string with your pinky in addition, you get a C/G chord which means it’s also a C chord (it has the notes C, E and G) but G is its lowest note.

You may want to check this lesson out:


Hi Mike, I’m sorry that it came across as glib and unhelpful. You have had further help from @Majik and @Jozsef

I am unsure if you still need clarification on anything. If you do then please ask. I am unsure currently what you are trying to find out and understandd however so won’t muddy the waters by adding in anything just now.
Cheers :slight_smile:

| Richard_close2u | JustinGuitar Official Guide, Approved Teacher & Moderator

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What is the difference between DIATONIC TRIAD & TRIAD ?

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Hi Saloni Diatonic mean in or part of a scale or Key. So diatonic triads would all belong to the same scale. The word Triad means 3 or 3 notes so any chord that contains only 3 notes are Triads.

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