Major or minor? · From Zero to Mozart

The single most useful thing your ear can do with harmony: hear a chord and know major or minor. It's a fast, binary call, and once it's automatic you can follow the mood of a piece as it plays.

The 3rd decides — so listen to the 3rd

Stage 4's the-four-triad-qualities showed you that major and minor differ by exactly one note: the middle one, the 3rd, a half step apart. Bright versus shaded, hopeful versus sad — that whole difference is that one note.

So don't try to take in the whole chord. Find the 3rd and sing it. Against the root: a major 3rd is the bright, open one; a minor 3rd is the closer, darker one. With practice you skip the singing and just know — but the 3rd is always where the answer lives.

54 bpm

Four rolled chords, each voiced root–5th–3rd (so the 3rd is the top note). For each: is it major or minor? Sing the top note against the bottom one if you need to — that's the 3rd, and it decides. Reveal to check. (Answers: major, minor, minor, major.)

Then the other two

Diminished (both thirds minor — tense, wants out) and augmented (both thirds major — floating, weightless) are rarer and you'll place them by their instability rather than by bright/dark. Drill those with the-four-triad-qualities; for now, the major/minor snap judgement is the one to make automatic.

Try it

Try

Play any two open strings a fifth apart — say D and A. That's a root and a 5th, no 3rd, no quality. Now add F♯ (high 2 on the D string) with your ear only — major. Slide it down to F natural — minor. Flip back and forth. You're hearing the exact half-step move that decides every major/minor call.

The usual mistake

Trying to judge the chord as a whole blur of sound. It's too much at once. Isolate the 3rd — that's the diagnostic note — and the call gets easy. The other mistake: confusing a plain open fifth (no 3rd) with major because it sounds "bright and stable." No 3rd means no quality yet; wait for the note that colours it.