3.2 Types of Seventh Chords and Chord Notation (Part 2)

This article is a continuation from the first half of Section 3.2.

3.2.5 Minor Major Seventh

Now, for the second half of seventh chords, we start with a rather complicated name. Minor, and yet major?

This is a seventh chord created by adding a minor triad to a note a major 7th above the root.

It is read as "C minor major seventh," but it is easier to understand if you interpret it by filling in the implied parts, like "C minor (triad plus) major seventh". The first "minor" applies to the triad part, and the latter "major" applies to the seventh.

It can also be viewed as an augmented triad built on the minor 3rd above the root.

As for notation, writing mmaj7 after the root note name is technically official, but since the 'm's are adjacent, it is hard to read (and they have opposite meanings, minor and major), so personally, I recommend writing it as "m△7" or "-△7" instead of mmaj7. You may also write "mM7", but in this case, be sure to write the lowercase and uppercase letters clearly and carefully.

The pronunciation is, as mentioned earlier, "C minor major seventh." It is long, but since omitting any more would change the meaning, it cannot be shortened. In Japanese music theory, there is no special name for this chord (though some people call it a minor-third major-seventh chord).

This chord is formed when you build a seventh chord using the tonic as the root in a harmonic minor scale or melodic minor scale. Its basic nature is the same as a minor triad, but the augmented 5th interval created by the 3rd and 7th notes produces a unique tension, resulting in a rather harsh-sounding chord.

As usual, I will show a few other examples.

3.2.6 Diminished Seventh

This is a diminished triad with a note a diminished 7th above the root added to it. The name of the 7th note is the name of the seventh chord itself (diminished 7th chord). Strictly speaking, in English it is the past participle "diminished," but in Japan, people generally don't worry about that and call it a diminished seventh. In Japanese music theory, it is called a diminished seventh chord.

It can also be thought of as a chord created by simply stacking minor 3rds three times.

As for notation, writing dim7 after the root note is official, but as mentioned with triads, sometimes it is written simply as dim to mean dim7. Writing a small circle and a 7 means the same thing. In any case, please note that in this chord, the 7 does not mean the default minor 7th, but rather a diminished 7th.

By the way, as we learned in the section on intervals, a diminished 7th is enharmonically equivalent to a major 6th. In actual sheet music, it is actually more common for the 7th note of a diminished seventh to be written as a major 6th rather than a diminished 7th (in the example of Cdim7 below, the notation on the left is easier to read, isn't it?).

When you build a seventh chord using the 7th note of the harmonic minor scale as the root, you get this chord. Its characteristics are not much different from a diminished triad.

Another characteristic of this chord is that if you ignore the root and focus only on the chord tones, you can say that "there are only three types of diminished sevenths". For example, the chord tones of Cdim7, E♭dim7, G♭dim7, and Adim7 are all the same (C, E♭, G♭, A), with only the root being different. If you consider these as one type, you can see that there are only three types in total, as shown below.

3.2.7 Minor Seventh Flat Fifth / Half-Diminished

This is a diminished triad with a minor 7th added from the root. It can also be viewed as a minor triad placed a minor third above the root.

This seventh chord has two names, which is a bit confusing, but you need to understand both.

The first name is "minor 7th flat 5th chord," which is named this way because it means "a minor seventh with the 5th note lowered by a half step".

The other name is "half-diminished 7th chord," which means a "chord that is only half-diminished." This "half-diminished" means that "the 5th note is lowered to a diminished interval, but the 7th note is not a diminished interval (it remains a minor interval)".

In Japanese music theory, it is called the leading-tone seventh chord, or the diminished-fifth minor-seventh chord.

As for notation, it is common to write "m7(-5) after the root note name" to express the meaning of minor seventh flat fifth. Writing "m7(♭5)" means exactly the same thing. Also, based on the half-diminished concept, sometimes a symbol like ∅, which is a small circle with a slash through it, is written to represent diminished.

There are quite a few people (in my experience) who cannot read this ∅, but since it is a simple and convenient notation, I would like to see it become more widespread. iReal Pro also uses ∅. It is also much easier to read as "C half-diminished." Well, if you want to say "C minor seventh flat fifth" every time, I won't stop you...

So, for my part, I recommend writing "∅" and reading it as "half-diminished". However, when writing sheet music yourself, if there is a risk that the reader cannot read ∅, it is kinder to write it as "m7(♭5)".

Now, regarding the characteristics of this chord, when you build a seventh chord using the 2nd note of the natural minor scale or the harmonic minor scale as the root, you get this chord.

Because this chord has a subdominant function in minor key songs, it appears frequently in minor key songs.

However, the same seventh chord is naturally formed even if you use the 7th note (leading tone) of the major scale as the root (the name "leading-toneseventh chord" is derived from this), so it is not rare for it to appear in major keys as well.

Finally, here are a few examples.

3.2.8 Major Seventh Sharp Fifth

This is an augmented triad with a major 7th added above the root. It is called a major 7th sharp 5th chord because it is a major seventh chord with the fifth raised by a half step. It can also be viewed as a major triad built on the major third above the root. There is no specific name for it in Japanese music theory.

As for notation, it is common to write the major seventh chord first, and then add C△7(♯5) followed by (+5) or (♯5). It is also understood if you write Caug△7.

As for how to read it, there is no specific abbreviation, so although it is a mouthful, it is best to say "C major seventh sharp fifth." You can also say "C augmented major seventh" and it will be understood.

This chord can be created by building a seventh chord using the third note of the harmonic minor scale or melodic minor scale as the root. It might be the most stylish-sounding of all the seventh chords.

With this, we have learned all seven types of seventh chords. Great work!

3.2.9 Chords with a Modified Fifth in a Dominant Seventh

For those of you thinking, "Wait, there's more?" I am very sorry. There are two more. Actually, in a dominant seventh chord, it is permissible to raise or lower the fifth by a half step. This appears frequently, especially in jazz music. Let's take a look at these chords as well.

First, let's consider why the modification of the fifth is permitted in a dominant seventh chord. As a review, a dominant seventh chord has a strong property of wanting to resolve a perfect fifth below (that is, dominant motion).

As shown in the score example above, the reasons for this property are:
1. When the root is viewed as the dominant note of the key, it has the power to resolve to the tonic a perfect fifth below.
2. At this time, the third note becomes the leading tone of the key, so it has the power to resolve to the tonic a half step above.
3. The diminished fifth (tritone) formed by the third and seventh notes is unstable, so it has the power to resolve.
...These are the three reasons. Take a good look at these three reasons again. Do you notice anything?

Yes, the fifth note of the dominant seventh (the D note in the case of G7) is not involved in any of these three reasons. In other words, even if the fifth is omitted, the function of the dominant seventh is not lost at all (the fifth is often omitted in actual performance as well).

If it's okay to omit it, then what if we shift it by a half step instead of omitting it? These chords were born from that idea. In fact, even if you shift the fifth by a half step, the function of the chord as a dominant seventh does not change. However, it certainly has a more stylish sound than a regular dominant seventh.

Now, let's take a brief look at each one.

3.2.9.1 Dominant Seventh Sharp Fifth

A seventh chord with the fifth of a dominant seventh raised by a half step is called a dominant seventh sharp fifth. I think some people also call it an augmented seventh. The notation methods are 7(♯5), 7(+5), aug7, and so on.

(Characteristics) It has a brighter sound than a standard dominant seventh. It pairs well with a special scale called the whole-tone scale.

3.2.9.2 Dominant Seventh Flat Fifth

A seventh chord with the fifth lowered by a half step is called a dominant seventh flat fifth. Notation methods include 7(♭5), 7(-5), and so on.

(Characteristics) Since both the root to the fifth and the third to the seventh form a diminished fifth (tritone), this is a chord with a very strong sense of instability. It is a chord that pairs well with the altered scale and the half-whole diminished scale (often called 'com-dim' in Japan).

Next Time Preview

Well, we have now learned all four types of triads and the seven plus two additional types of seventh chords. You have done a great job! However, this is not actually the end. Rome wasn't built in a day, and neither are chords.

All the chords we have learned so far were created by stacking thirds from the root two or three times. However, in reality, chords can be created in other ways as well. What if we stack something other than thirds? What if we stack thirds four, five, or six times?

Next time, we will actually learn about these kinds of chords. From here on, things will get even more complex. But that is precisely why it is important to organize and understand them one by one. Let's take it slow!

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