The most basic chord in music is the Triad – or three-note chord.  In practice, we don’t actually call them triads – instead, we reference triads as simply major or minor chords – examples:  C  Dmi  Emi F  G  Ami.  There are times when two-note chord fragments are useful for keeping multi-instrument arrangements clean sounding.  Otherwise, the Triad reigns king in the world of music due to its clean, strong sound and versatility.

Chords come from scales.  For this study, we’ll be using the diatonic major scale, since we are all familiar with its structure by now.  To find the notes of any triad, we simply extract every other note from a scale.  The first chord in the C scale is the C chord (of course!), whose three notes are C   E   G:

1                3          5
C       D        E  F       G       A      B  C

We chose C, skipped the 2nd note D, chose the third note E, skipped the 4th note F, and chose the 5th note G. (every other note)

So, we chose the first, third, and fifth note, which is exactly how we refer to these notes.  Another name for the first note is the “Root”.  The third note is called the 3rd.  And the fifth note is called (you guessed it) the 5th.  So, we have Root, 3rd, and 5th as our chord note names, in this case C E G.

The interval between each note in a Triad is called a 3rd – since they are three notes apart from each other.  So, a triad is comprised of two 3rd intervals joined together, in this case C to E is our first 3rd interval, while E to G is our second 3rd interval.

Earlier we learned that half-step intervals are also called minor 2nds – they are two alpha names apart (E to F)  Another name for whole-step intervals is major 2nd – also two alpha names apart, but in this case the interval is a whole-step (C toD ).

Notice that the C to E third interval is comprised of two whole steps.  Another name for two whole steps is major 3rd:

1           3
C     D     E =  Root to third
  1      1    =  two whole steps = major 3rd interval.

Looking at the 2nd third interval in a triad, we see that E to G is comprised of a half-step joined with a whole step, or 1 ½ steps total.  This interval is refereed to as a minor 3rd:

3          5
E   F      G =  third to fifth
 1/2    1    =  1/2 + 1 step = minor 3rd interval.

Joining them both together we get:

1       3       5   =  Root, 3rd, 5th
C       E       G   =  C major triad
    2       1½      =  Major triad structure

So, a major triad is comprised of a major 3rd joined with a minor 3rd, the structure being 2 plus 1 ½.

The first chord in all diatonic major keys is a major triad – in this case C major triad, otherwise known simply as C, since protocol says all triads are major unless indicated otherwise.

Now see what happens if we begin on D (2nd note in the key of C)

       1          3             5
C      D      E   F      G      A      B   C

Again, we chose every other note, this time resulting in D F A, the root, 3rd, and 5th.

In this case, the first 3rd interval is a minor 3rd:

1          3
D      E   F  =  Root to third
    1    ½    =  1 + 1/2 steps = minor 3rd interval

While the second 3rd interval in our chord is major:

3             5
F      G      A =  third to fifth
    1      1    =  1 + 1 steps = major 3rd interval

Join both of these 3rds together and we get:

1        3        5   =  Root, 3rd, 5th
D        F        A   =  D minor triad

  1 1/2       1       =  minor triad structure

So, a minor triad structure is the opposite of a major triad structure:

2   +  1 ½  =  major triad structure  (C)

1 ½  +  2    =  minor triad structure  (Dmi)

Note the distance from the Root to 5th is the same in both cases (3 ½ steps), it is only the 3rd note of the chord that changes from major to minor.  Or, you can change a C major into a C minor by lowering its 3rd by a half-step:

C     E G  =  C major

C     Eb G  =  C minor

Conversely, you can change a minor chord into a major by raising its 3rd by a half step:

D     F A  =  D minor

D     F# A =  D major

The third determines a chord’s tonality or “quality”, while the root and 5th only determines its pitch.

If I played just C and G together and asked you what chord I was playing, you do not yet have enough information to answer the question – since C and G (root and 5th) appear in both C major and C minor.  It is the 3rd that determines the type of chord.

So far we’ve taken the first two notes of the C diatonic major scale ( C D), and made them into chords (C and Dmi).  Every diationic scale has seven chords, since each note can become the root of a chord.  So, we have five more chords left in our C diatonic major scale to extract.  We will do just that in our next blog.

Also, so far, we have learned a couple of new intervals.  Here are the intervals we have learned up to this point, with their distances on a guitar neck:

Interval    Steps    Frets    Example
Minor 2nd     ½        1       C - Db
Major 2nd     1        2       C - D
Minor 3rd     1 ½      3       C - Eb
Major 3rd     2        4       C - E
Perfect 5th   3 ½      7       C – G

Congratulations! You are well on your way to learning chord theory that will lead to an understanding of every chord in music!  A very small percentage of musicians I know understand even these basic chord concepts – by far the most important discussed up to this point.  I encourage you to go over this information until it is solid, and as always do not hesitate to ask any question.

Until next time, I remain,

Musically yours,

Al