The Half-Diminished 7th Sound

Built upward, the half-diminished 7th is a minor 3rd, then a minor 3rd, then a major 3rd — 4 tones in all. In a drill it arrives in a key you did not choose, so the only thing left to listen to is that shape.

Near missesdiminished triad, minor 7th and diminished 7th — each one is this chord with a single tone moved, which is why a wrong answer here is almost never random.

Same notes, different name. Played without a root in the bass, this is the exact pitch-class set of the minor 6th chord — not a near miss but a genuine tie. Rounds that hide the root never put the two in the same answer list, because a question with two right answers teaches nothing.

It sits in the edge tier — the shapes whose difficulty is that they refuse to name a root.