Music theory chord chart

In my own time, I decided to create a chord chart that helps bridge the gap between theorists (who use Roman numeral analysis) and contemporary musicians (who use chord names).

Below are my result, with a bit of color-coding to make make things clearer.




So what does it all mean? Well, here are some guidelines for starters:

• Keys on the left-hand side, with logical chords in that row.
• Functions are written across the top row, with corresponding chords in the columns.
• Light gray chords are unique to major; dark gray to natural minor. But that doesn't have to stop you from borrowing chords from the other mode.
• In general, for those of you who didn't know, chord progressions tend to follow a pattern of tonic - ... - dominant - tonic, with other chords interspersed. "Predominant" chords can prepare a dominant chord, and others can precede a predominant.
• Pay attention to the indicated color, which generally match the name of the function. Some intermediary chords have a different color, and that's because depending on their usage, they fall under either category (to the left or right).
• In general, chords within the same category can be substituted with another, regardless of accidentals (chord alteration from the norm).
• That slash notation (i.e. X/Y) are secondary dominants, noted for convenience. What that means is that the indicated chord (call it "Z") functions as a dominant "X" of (i.e. prepares or expects) the chord "Y". So if you used that "Z" chord, the next chord you expect is "Y". But as I mentioned in that last point, instead of "Y" you could use another chord in Y's category.

Some other helpful hints and observations:

• Seventh chords weren't considered, but generally they serve the function of the triad on which you're stacking that seventh.
• The chords "vi" and "bVI" are orange (not yellow) because they can be substituted for the tonic on occasion in what's referred to as a "deceptive cadence".
• Just because a chord has funky symbols like flat signs or slashes, doesn't mean you should shy away from it. They actually sound pretty cool and can really add flavor to your music.

And now for my own comments. It's theory related, so feel free to skip the rest:

• Common practice / classical theory is a bit more rigid than contemporary music (primarily using only the notes within the key with subtle alterations). I think this chart helps show how "foreign" chords (i.e. beyond the key) connect to other chords.
• I didn't realize that the "bII" chord can also be a dominant ("tritone substitution"). Usually it appears in first inversion (i.e. with the third in the bass) as the "neapolitan".
• The "bVII" isn't used much functionally in old-school music theory, but I've heard enough examples of it as a dominant. Oh, and speaking of the dominant, just because something's called a dominant doesn't mean it has to be the penultimate chord. Have a ball.
• I tried to figure out a way to fit "bV" (or any chord built on the tritone), but I couldn't find it. I also wasn't sure where to fit the minor "v", but I guess it would be a dominant.

Note: This isn't an exhaustive chart, by any means. Just a basic guide to how to easily use chords. I hope someone out there finds this useful. Perhaps a person not as versed in theory but still eager to compose.