The open chords
Chords
are the most important thing to concentrate on. It's much more
important to know the chord than the note. Chords set the rules.
There are several qualities we can ascribe to chords. The two
main qualities are Major and minor.
Here are the open chords, so called I guess because they take
advantage of the open strings.
Majors first: Don't play X string
Chords are named after their Root note, also
known as the Tonic or the One (1). It's important to realize that
all of the chords
above have the same quality — MAJOR — even if they
all look different. Without having to go into details at this stage,
they are made up of the same ingredients, namely the first (1),
third (3) and fifth (5) notes of their scale. The tuning of the
guitar (and the fact that the strings end at the nut) make for
the difference in appearance.
Here are the open minors:
Once again, it's important to understand that all
minor chords have the same quality -- MINOR.
Compare these to their MAJOR counterparts above and you'll notice
that only one
note has changed: the treble note has been lowered one fret.
It happens to be the third (3). So you could say that minor
chords are really just majors with a flat (3).
As all major keys consist of 3 major chords, 3 minors and a
half diminished (you don't have to worry about it for a long
time), you'll have to be familiar with both forms, and you should
(eventually) be able to move between them all smoothly and accurately.
Some chord progressions  | 
