Why does the iii chord seem to be usually avoided in many styles?

Question

Chord iii in major key is often avoided. This transcends specific styles. Popular music almost never uses chord iii, classical music usually shies away from it even with its large harmonic potential, even some of the most dissonant musical styles have a tendency to circumvent chord iii. Some textbooks even advise you to avoid chord iii at all costs. I've always found this odd. I find chord iii's mediant and leading tone contradiction to have a really beautiful and unique sound in a major key, and I can think of many progressions where that sound would work really well.

Why is chord iii avoided in so many styles?

Answer 1

I'll go a slightly different direction with my answer and say that I think this is a misconception. And frankly, I blame lackluster textbooks for it.

I recall Kostka/Payne's Tonal Harmony in my undergraduate basically saying "this chord is weird, so don't use it." Nothing could be further from the truth! It's incredibly colorful, and it's a great way to harmonize the leading tone in a way that almost masks its function as the leading tone.

The Beatles used the iii chord all the time: "Can't Buy Me Love" begins with a iii chord right on "love," and "I Feel Fine" uses it right on "I'm so glad." (I could keep going, but I won't.) "Puff the Magic Dragon" by Peter, Paul, and Mary uses a iii chord in its chorus. In the classical style it's used rather frequently both in sequences and in chord progressions moving to the IV or vi chord. It's used to great effect in the second movement of Shostakovich's Second Piano Concerto, one of my favorite piano concertos ever, and in Mahler's Second Symphony—one of my favorite symphonies ever!—Mahler uses it to great effect in two different critical brass moments (in the fourth and fifth movements).

True, the iii chord is probably the least used diatonic triad in tonal music, but something has to come last. But I think the musical community is wrong to suggest that it's ever avoided; it brings a wonderful new sound to the harmonic palette!

Answer 2

Just an addendum to the other answers:

The iii chord is central to the so-called royal road progression, which is used in a great deal of Japanese pop music, especially anime.

The royal road progression is IV7 V7 iii7 vi7. Both the iii and the vi serve as substitutes for the I chord, leaving the progression ambiguous in terms of a cadence point.

One example is the song "Star!!", the opening song for The Idolmaster: Cinderella Girls.

In the screenshot below, the Royal Road Progression is highlighted:

(Image Source: "The History of the "Anime Canon" Chord Progression" by Cadence Hira. I highly recommend the entire 30-minute video.)

A list of songs containing this progression can be found on the progression's Wikipedia page: "IV△7–V7–iii7–vi progression"

David Bennett Piano also has a list contained in his YouTube video "Japan's favourite chord progression and why it works".

And there is also Rick Astley's "Never Gonna Give You Up". (No, you're not being Rick-rolled.) It is sometimes cited as an example of the IV V iii VI progression, but it's not.

It's actually ii7 V iii VI. (So, sorry, but here's the video anyway.)

Answer 3

Richard may be correct that Kostka/Payne's Tonal Harmony and probably others say this chord is weird. But is it avoided? Of cours it won't substitute the tonic as homechord and final chord. But it is often used in a turnaround like I vi ii V: I vi ii V -> iii vi ii V ... for continution (avoiding the homechord feeling).

Answer 4

Although Richard's answer is accepted and correct, since he references the attitude in Kostka/Payne's Tonal Harmony, here's what another popular textbook has to say regarding the relative rarity of iii. From Harmony, fifth edition by Piston & DeVoto, Chapter 3 "Harmonic Progression in the Major Mode: Principles of Voice Leading":

The following generalizations are based on observations of usage by composers in common practice. They are not proposed as a set of strict rules to be rigidly adhered to.

(Emphasis mine, to show that this is intended as descriptive, rather than prescriptive.)

I is followed by IV or V, sometimes vi, less often ii or iii.

ii is followed by V, sometimes IV or vi, less often I or iii.

iii is followed by vi, sometimes IV, less often I, ii, or V.

IV is followed by V, sometimes I or ii, less often iii or vi.

V is followed by I, sometimes IV or vi, less often ii or iii.

vi is followed by ii or V, sometimes iii or IV, less often I.

vii° is followed by I or iii, sometimes vi, less often ii, IV, or V.

(Note that Piston & DeVoto do not follow the common convention of lower-case roman numerals for the minor triads; I've adjusted the above quote to avoid confusion about chord quality.)

In 4 of the 7 cases, the iii is in the "less often" column. In one case, it's in the "sometimes" column. Only after the vii° is it among the common choices

This list seems to reinforce the notion that the iii is rare, but not because it's to be avoided, only because it's special.

If this list does suggest anything like avoidance, it would be of the vii°. It never appears following anything in the list. A Stochastic chord progression based on this list would only ever produce a vii° if it started there.

Answer 5

Maybe because it sounds rather like a weak version of I. In the same way that vii sounds like a weak, rootless V7. But is it avoided THAT much? Let it be your secret weapon!

Answer 6

Whereas the vi and ii chords use two of the three minor scales, the scale of the iii chord does not. So it doesn't function well in the circle of fifths cadence. Therefore it's mostly used as a sub for the I.