E Major
0 - 4 - 7Root + major 3rd + perfect 5th
About E Major
E major is the loudest chord on the guitar. All six strings sound, three of them open, and the lowest note is the open low E — the deepest pitch the instrument has in standard tuning. Nothing else in first position moves as much air.
The notes
E, G♯, B — root, major third, perfect fifth. The open E, B and high E strings already belong to the chord, so only three notes need fretting, and the shape sits in the easiest part of the neck.
Move the G♯ down one fret to G and the chord becomes E minor — two fingers instead of three. That pair is usually the first thing a guitarist learns, precisely because the difference is so small and so audible.
Why this shape matters beyond itself
The E major shape, barred, becomes every major chord on the neck: at the first fret it is F, at the third G, at the fifth A. Learning this one fingering is learning twelve chords, and that is why it is taught before its own key is discussed.
The same is true of E minor, which barred gives every minor chord. Between the two shapes a player covers most of the harmony in popular music without knowing another form.
Where it shows up
E major is the tonic of its own key and the V of A major. In blues and rock it is the home chord more often than any other, because the open low E gives riffs a foundation no other key offers on this instrument.
It is also why so much guitar music sits in E and A: not because those keys suit the human voice, but because they suit the six strings. Singers transpose; guitarists tend not to.