Why Do Jazz Pianists Use Modes?

Is this you?:

"I know what modes are. But why should I care, as a jazz pianist?"

If so, you're not alone. (I recently had two people ask me about this over just two days). Unfortunately, a lot of resources such as textbooks and videos don't necessarily go into this. They'll talk about the "what" of modes without talking about the "why." That can leave you questioning whether you have just wasted your time learning about a sort of obscure "exercise" that would only be of real interest to music theorists.

Well, I'm here to say: nope! Not true! Modes are hugely important for jazz! Here's why: using modes keeps us in the proper key, and it allows us to properly emphasize the strong notes (when we want to).

Let's dig deeper. When we play over some chord, in some key, it's good for us to be able to do two things:

1. We should be able to strongly "project" the chord when we want to, by emphasizing the chord tones. (Example: over a D minor chord in C major, we emphasize D, F, and A).

2. We should also be able to strongly "project" what key we're actually in, by filling in the "other notes" (the non-chord tones), according to what key we're actually in. (Example: over the D minor chord in C major, we fill in the chord tones with the other notes from C major: E, G, B, and C).

Now, let's look at two common approaches to playing over chords. You'll see that each approach gets you only halfway there; it meets one of the goals above, but not the other.

1. Just play over the chord, emphasizing the chord tones. What it solves: you're strongly projecting the chord, by emphasizing chord tones! The problem it leaves: what about the non-chord tones? You're left either arpeggiating chord tones only (which can sound awkward or unnatural after a while), or hunting and pecking for non-chord tones by ear, which can weaken the sense of what key you are in.

2. Just play in whatever key you're in! (In this case, just think about the C major scale, while you're playing over that D minor chord). What it solves: it gives you the correct non-chord tones! And that gives you a strong grounding into the key. The problem it leaves: it doesn't set you up properly to emphasize the chord tones. In fact, you'll very possibly de-emphasize the chord tones (D, F, and A), and emphasize non-chord tones instead (C, E, and G).

I've known some people who use one of the above approaches. Perhaps you have been there yourself. For example, maybe you've always just sort of approached a chord by arpeggiating the chord tones. That gives you a strong sound, but you might sometimes get lost, searching for the "in-between" notes.

Now, let's use modes! In this case, we'll use the D dorian scale over that D minor chord.

1. We're strongly projecting the chord! We're likely to emphasize the correct chord tones (D, F, A), because we're thinking of this as a type of D scale, and not as a type of C scale.

2. We're strongly projecting the key! That's because the D dorian scale contains those notes that come from the key of C major.

What you should do about all this:

This is the tough part. You need to learn your modes at the piano. You should eventually learn all seven of them, in all twelve keys. This is a huge undertaking, but think about the payoff: if you knew all your modes in all twelve keys, and if you knew what roman numeral chord you were on at any given time, you'd have a great foundation for playing over it! This is well-worth the effort, and there are logical ways to step through this process. It's something that I have helped guide many of my students through. Be patient with yourself, work on one mode at a time, and carefully observe the relationship between the mode and its corresponding place in the key. You've got this!