Question: Hi Albert,
What are the chords that I really, really need to know as an intermediate piano player? Here's my guess: Major, minor, diminished, augmented, major and minor 6th, major and minor dominant 7th, and Major 7th. Not sure about sus chords. What say you? Thanks.Willard Crawford (Llano, California, USA)
Albert's reply: You got it! The only clarifications I'd make are, first, that major and minor 6th refer to intervals (between two notes)—it's better to say "major with added 6th" and "minor with added 6th" when referring to chords.
Secondly, there's no such thing as a "major dominant seventh" or a "minor dominant seventh." A major seventh consists of three major thirds above a root; a minor seventh consists of a minor third, a major third, then another minor third above the root; and a dominant seventh (also called a "major-minor seventh") consists of a major third, a minor third, then another minor third above a root. (In the case of a dominant seventh, the root of the chord is scale degree 5, i.e., the fifth note in the scale.)
The basic triads and sevenths are all contained in the free piano chord charts available from this site. The chart of basic piano chords consists of major, minor, diminished and augmented triads, as well as dominant seventh, diminished seventh, minor seventh and major seventh chords.
The advanced piano chord chart goes further, containing major and minor triads with added sixths, suspended 4 and 2, dominant seventh with suspended 4, minor-major seventh, half-diminished seventh and ninth chords.
With the exception of minor-major sevenths and half-diminished sevenths, all the chords in the advanced piano chord chart can easily be figured out once you have a grasp of basic music theory. For example, "sus4" is a triad with a fourth, rather than third, over the root; the fourth must resolve downward to the third of the chord. "sus2" has a second above the root in place of the third; similarly, the second must resolve to the third of the chord.
Added sixths are very simple—they're nothing but major or minor triads with a sixth above the root. What's interesting about them is that the sixth is not functional—it's merely there for added color and doesn't really need to lead anywhere, unlike functional harmonic tones.
Even the ninth chords in the advanced chord chart are actually simple: They're nothing more than dominant sevenths with an extra major third stacked on top. Like the sixth in added sixth chords, the ninth is generally there for color.
My recommendation is therefore just to learn all the chords in the basic piano chord chart, then to learn the remaining two types of seventh chord (minor-major seventh and half-diminished seventh) once you're very comfortable with the basic chords. From there, once you know the basic chords and your piano scales, the other chords will be self-explanatory and you'll be able to construct them on the fly.