Open chords
The open chords (a.k.a. open-position chords or "cowboy chords") are the most common chords in several styles. They are known as open chords because some of the strings are played without a finger placed on them, opposite to the closed-position chords which doesn't involve any open strings. Another definition is that they span more than one octave, contrary to closed chords (this is more in the context of voicings and piano however).
Some common examples:C
D6
Em
Fmaj7
G
Gmaj7
Am7
A7
All these chords are open, meaning that one or several strings is played loose and not fretted. The chords are suitable for many styles, among some are contemporary pop and singer-songwriter. See progressions further down the page.
C open chords
C
Cm
Cmaj7
C7
C6
C13
Chord note structure
Here is information about which notes each chord consists of and also without duplicates. Observe that you sometimes strum more strings than the numbers of the notes of the chord you are playing, and this is because some notes are played twice (or trice in rare occasions), but in different octaves.
D open chords
D
Dm
Dmaj7
Dm7
D7
D6
Dm6
Dm9
D13
Comments
All these chords are open, meaning that one or several strings is played open without any fingers pressing down. The chords are suitable for many styles, among some are contemporary pop and singer-songwriter. Notice that D13 include fingerings on the fourth and fifth fret.
E open chords
E
Em
Emaj7
Em7
E7
E6
Em6
Emaj9
Em9
Comments
All these chords are open, meaning that one or several strings is played without loose strings and not fretted.
F open chords
F
Fmaj7
F7
F11
G open chords
G
Gm
Gmaj7
Gm7
G7
G6
Gm6
Gmaj9
Comments
All these chords are in open position, meaning that one or several strings is played without any fingers pressing down. Observe that Gm and Gm7 are more common to play as barre chords and that Gm7 is an inversion (Gm7/Bb). An alternative fingering for G major that also is common is 320033, in which the less open ringing strings gives a more percussive sound.
A open chords
A
Am
Amaj7
Am7
A7
A6
Am6
Amaj9
Am9
Comments
Some of the F chords are not the standard, but are chosen here to qualify as open chords. Many prefer to play some of the F chords as barre chords instead.
F minor is not included since no proper open position version are available. The same thing with Fm7, Fm6, F6 and some other F chords.
F6 is commonly played as XX3231 (with the 5th omitted), but one alternative as an open chord is 100211.
Chord progressions
Some suggestion of possible progressions using the chords illustrated on the page:
C – Fmaj7 – G – C
G – D6 – Em – A7 – G
Em – C – G – Am7
Comments
Open chords refer to the way a chord is constructed, by including open strings and is often used to describe a chord that is not a barre chord. There is no accurate term to otherwise describe a chord that is not open and not a barre chord (closed chord as a term in this case is somewhat problematic).
An open chord can be a C or it can be a C7 or it can be a Cadd9. You can in most cases play a certain chord as a barre or as an open chord, the difference is the sound (and the shape of course).
Open chords work very well on a steel-string acoustic guitar or an electric guitar with clean sound from the amplifier. The tones ring out nice and have a pleasant crispy sound.
The drawback with open chords is that some of them has quite difficult fingerings. From the link list above you can choose from notes C - D - E - F - G - A - B whereas C# (or Db), D#, F#, G# and A# are missing. This is because these chords in many cases doesn't have natural fingerings in the standard tuning and because of that often is played as barre chords or with a capo.
The next step after you have learned the common open chords is learning other kinds of chords to put in your chord progressions, such as barre chords and voicings. This can in many ways enrich your sound and give new methods to your guitar playing. It's not about knowing all the chords that exist, but to expand your knowledge and increase the ways you can approach your guitar, either you are playing songs of other's or creating your own.
If you want to know more about the theory regarding chords, read What is a chord?