Built at 2 AM,
because the tool didn't exist.

Every jazz teacher eventually says it: "Take it through all 12 keys." Every student nods — and then practices C major for another week.

Not because they don't understand the voicing. Because there was no tool that made drilling all 12 keys fast, measurable, and actually engaging.

Chord Trainer is that tool. MIDI-validated, timed per chord, weakness analysis built in. It works at 2 AM when no class is running.