What you're training
A modulation pivots a progression from one key to another, usually through a shared chord followed by a ii-V that tonicizes the new home. Every round here opens the same way — a plain I-IV-I frame in C major — so the only variable is what happens next: does the progression stay in C, or pivot through a pre-dominant and dominant into a different key entirely? Each round ends on a held final chord, so the answer is always audible in where it lands.
Two levels, one skill
Level 1 asks the binary question first: did the progression stay home, or change key? Level 2 raises the bar — every round now modulates, and you name the target: G (the dominant), F (the subdominant), or A minor (the relative minor). Each target uses its own ii-V into the new tonic, so the pull is always audible, not just theoretical.
Go deeper
Where real pieces change key — mined with correlations → surveys real modulations across a corpus of pieces and how often each target shows up. The theory: modulation → covers pivot chords and the ii-V mechanics behind the pull. A cadence that surprises without ever leaving the key → is a related trick, if you want the twist that stays home instead of pivoting away.
Where it fits
Comfortable with secondary dominants and cadence resolution already? Modulation is the next layer — the same dominant pull you already hear, now strong enough to drag the whole progression into a new home. The full drill ladder has everything else.