What a triad is · From Zero to Mozart

A triad is three notes stacked in thirds: a bottom note (the root), a third above it, and a fifth above the root. Stack two thirds and you have one. It's the atom of harmony — nearly every chord in tonal music is a triad, or a triad with something added.

See it — the snowman

60 bpm

The G major triad — G, B, D — written in close position: three noteheads on one stem, all on lines, a little snowman. Then the same three notes one at a time. Root to 5th is a perfect 5th; the two thirds inside give it its flavour. (On the violin you'd spread this out to play it — see below.)

You've met this chord before — Stage 3's Reading double stops and chords printed exactly this stack and called it "a G major chord." Now you know why it's a G major chord: it's a triad built on G, and the third inside it (G up to B) is a major third.

Block or broken

The same three notes can be a chord (all at once, stacked on one stem) or an arpeggio (one after another — you'll get a whole movement on those). Same notes, same triad, different surface:

66 bpm

The G triad rolled as a chord (open G, open D, B on the A string — a playable voicing), then spread out as an arpeggio. Your ear hears 'G major' either way.

Try it

Try

Build the G major triad note by note, low to high: open G, then B on the G string (high 2), then D (open D string). Hold each note in your ear before you add the next. Then play them as a fast roll, bottom to top, on one bow. That rolled shape is how a violinist plays a chord.

The usual mistake

Reading a stack of noteheads as a fast run of separate notes. The tell is on the page: notes side by side and beamed happen one after another; notes stacked on one stem happen together. (Stage 2 and Stage 3 both hammered this — it's the single most common misreading of string music.)