Chord quality

Major, minor, or stranger

Chord-quality ear training is about hearing the character of a chord — bright, dark, or somewhere in between — in a single strum.

The drills

major vs minor  the first split
add 7ths        maj7, dom7, min7
sus chords      sus4 and sus2, the "waiting" sound
diminished      the tense little stack

Why it matters

Transcribing and jamming both come down to recognizing chords fast. This is the fastest route there.