What you're training
The Neapolitan chord — bII — is a major triad built on the flatted 2nd scale degree, almost always heard in first inversion (bII6). In A minor that's Bb–D–F, voiced D–F–Bb from the bass up. Every question in this drill keeps the D–F base identical to the plain diatonic ii°6 (D–F–B) — only the top note moves, a single half step from B down to Bb. That one semitone is the entire lesson: it's the difference between an ordinary diminished pre-dominant and the Neapolitan's signature dark, flat-second color.
Two levels, one skill
Level 1 plays a three-chord pre-dominant–dominant–tonic progression in A minor and asks the binary question: was that pre-dominant the diatonic ii°, or the Neapolitan bII? Level 2 raises the bar — a four-chord progression now has two pre-dominant slots, and exactly one of them is the Neapolitan. You name which position it was in, 2nd or 3rd, so the ear has to catch the flat top note wherever it lands, not just recognize it in a fixed spot.
Go deeper
This drill is Trio 4 of the chromatic-harmony series — the Neapolitan's one-semitone darkening of an ordinary pre-dominant. The theory: Neapolitan sixth chords → covers where the chord comes from and how it's notated. For the real-world payoff, 27 Neapolitans across 18 real pieces — the Moonlight's famous pair — playable → lets you hear every one in context. Another kind of borrowed color — modal mixture → is the other lane of this series, if you want a chord borrowed from the parallel minor instead of one built on a flatted scale degree.
Where it fits
Comfortable with chord quality and cadence resolution already? The Neapolitan is a focused, single-semitone chromaticism — a great next step after borrowed chords. The full drill ladder has everything else.