E Minor
m
0 - 3 - 7Root + minor 3rd + perfect 5th
About E Minor
E minor is the first chord most guitarists ever play, and the reason is physical: two fingers, no barre, all six strings ringing. It is the only common minor chord where the guitar's open tuning does most of the work — the low E, the B and the high E are already the notes you need.
The notes
E, G, B — root, minor third, perfect fifth. On a guitar in standard tuning three of the six strings already sound two of those notes, which is why the shape needs so little. Fret the A string at the second and the D string at the second, and every remaining string is either E, G or B.
Compare it with E major, where a third finger raises G to G♯. That one finger is the whole difference between the two chords, and moving it back and forth is the cheapest way to hear what minor actually means.
Why it sounds full when other minors sound thin
Four of the six strings are open, so the chord keeps ringing after the pick leaves. Open strings also spread the notes over a wider range than a barre chord can — the lowest E and the highest E are two octaves apart, and the ear reads that spacing as depth rather than volume.
This is also why E minor is a common key for guitar songs that need to sound large with no arrangement. The instrument is loudest and most resonant here, and no other minor key gets that for free.
Where it shows up
E minor is the tonic of its own key, the vi of G major and the ii of D major. All three are guitar keys, so the chord turns up constantly — Em–C–G–D is probably the single most played progression on the instrument.
It is also the usual first stop when a song modulates downward in mood: a chorus in G that drops to E minor for the bridge is asking for exactly the darkening this chord gives without changing a single sharp or flat.