In the Guitar Chords for Beginners page, all of the chords belong in the Key of G Major. A chord key is a musical term for a group of chords based on their position in a major scale.
You can use these beginner chords together to play chord progressions that are used in many songs in all styles of music.
The Key of G Major begins with the G Major chord as the I chord. This is the chord where the chord progression will typically begin or end on, making it a chord of rest.
The C Major chord is the 4th chord in the key of G Major. The IV chord of a chord progression can build slight tension betweem it and the I chord.
The D Major chord is the 5th chord in the key of G Major and is used to build more tension than the IV chord of the progression and can lead back to the I chord, a chord of rest.
Playing the G Major, C Major and D Major chords together in a chord progression:
G C D e|--3--3--3--3--|--0--0--0--0--|--2--2--2--2--|--2--2--2--2--| B|--0--0--0--0--|--1--1--1--1--|--3--3--3--3--|--3--3--3--3--| G|--0--0--0--0--|--0--0--0--0--|--2--2--2--2--|--2--2--2--2--| D|--0--0--0--0--|--2--2--2--2--|--0--0--0--0--|--0--0--0--0--| A|--2--2--2--2--|--3--3--3--3--|--------------|--------------| E|--3--3--3--3--|--------------|--------------|--------------|
The 6th chord in the key of G Major is the E minor chord. Adding this chord to the chord I - IV - V progression creates a very popular chord progression in music.
G E C D e|--3--3--3--3--|--0--0--0--0--|--0--0--0--0--|--2--2--2--2--| B|--0--0--0--0--|--0--0--0--0--|--1--1--1--1--|--3--3--3--3--| G|--0--0--0--0--|--0--0--0--0--|--0--0--0--0--|--2--2--2--2--| D|--0--0--0--0--|--2--2--2--2--|--2--2--2--2--|--0--0--0--0--| A|--2--2--2--2--|--2--2--2--2--|--3--3--3--3--|--------------| E|--3--3--3--3--|--0--0--0--0--|--------------|--------------|