Chord progressions or chord sequences - combinations of chords that forms an harmonic interval.

Chord harmonization

Major triad chord harmonization in the major keys -i.e. what chords are diatonic to each of the twelve major keys?

Key I ii iii IV V vi viiº
C major C Dm Em F G Am Bdim
F major F Gm Am Bb C Dm Edim
Bb major Bb Cm Dm Eb F Gm Adim
Eb major Eb Fm Gm Ab Bb Cm Ddim
Ab major Ab Bbm Cm Db Eb Fm Gdim
Db major Db Ebm Fm Gb Ab Bbm Cdim
Gb major Gb Abm Bbm B Db Ebm Fdim
B major B C#m D#m E F# G#m A#dim
E major E F#m G#m A B C#m D#dim
A major A Bm C#m D E F#m G#dim
D major D Em F#m G A Bm C#dim
G major G Am Bm C D Em F#dim
Major Minors Majors Minors
Lower case roman numerals signifies minor chord degree. Uppercase roman numerals signifies major

In a chord progression the chords share some notes. And the notes they share are usually taken from a single scale.

Take the chord progression C Major - F Major - G Major.

The notes of C Major chord: C,E,G

The notes of F Major chord: F,A,C

The notes of G Major chord: G,B,D

In a chord progression C Major - F Major - G Major, the chords can be built from the
C Major Scale:

     C Major    C Major 
     Scale      Scale      C Major    F Major  G major 
  0  EADGBE     000000     0||0|0     ||||||   ||000| 
  1  F|||RF     0|||R0     ||||R|     R|||0R   |||||| 
  2  |BEA||     |000||     ||0|||     |||0||   |0|||| 
  3  GRF|DG     0R0|00     |R||||     |0R|||   R||||R 
  4  |||B||     |||0||     ECEGCE     FCFACF   GBDGBG 
  5  ADGCEA     000R00 
  6  ||||F|     ||||0| 
  7  BEAD|B     0000|0 
  8  RF||GR     R0||0R 
  9  ||BE||     ||00|| 
  10 DGRFAD     00R000 
  11 ||||||     |||||| 
                       

How to find chords progession.

The circle of fifth (of fourths counter clockwise) is very useful tool to find chord progressions.

Common chords progession

3 Chord Progression

The I-IV-V - a.k.a the 3 Chord Progression - must be the most commonly used chord sequence in rock and blues, country, and soul.

Examples:

G-C-D (G Major - C Major - D Major) or G-C-D7

A-D-E or A-D-E7. The seventh chord increases the tension.

C-F-G or C-F-G7

E-A-B or E-A-B7

D-G-A or D-G-A7

F-Bb-C or F-Bb-C7

“GGG CC DDD CC”

“GGGG GGGG CCCC GGGG DDDD CCCC GGGG”

“DDD CCC GGG GGG”.

I-IV-V7

E-A-B7

ii-V-I

A ii-V-I in the key of G would look like this: / Am7 / D7 / Gmaj7 / Gmaj7 /

With simplified chords (no fifth), this progression could be playd like this:

    ii     V    I               ii     V    I 
   Am7    D7  Gmaj7            Am7    D7   Gmaj7 
 |-------------------|       |-------------------| 
 |-------------------|       |----5----5----3----| 
 |----5----5----4----|       |----5----5----4----| 
 |----5----4----4----|       |----5----4----4----| 
 |---------5---------|       |---------5---------| 
 |----5---------3----|       |----5---------3----| 
                             With the 5th included. 

Another example of a ii-V-I in the key of C: / Dm7 / G7 / Cmaj7 / Cmaj7 /

    ii     V  V     I 
   Dm7    G7  G7  Cmaj7 
 |---------7------------| 
 |----6----6--3----5----| 
 |----5----7--4----4----| 
 |----7----5--3----5----| 
 |----5------------3----| 
 |------------3---------| 

With b5 chord substitution of the V chord.

     ii    V    I             ii    V     I       
     Am7  Ab7  Gmaj7          Dm7   Db7  Cmaj7    
 |-------------------|    |--------------------|  
 |-------------------|    |----6----6-----5----|  
 |----5----5----4----|    |----5----4-----4----|  
 |----5----4----4----|    |----7----6-----5----|  
 |-------------------|    |----5----4-----3----|  
 |----5----4----3----|    |--------------------|  

Or even more simplfied, without the bass

    ii    V   I     
   Am7   Ab7 Gmaj7  
 |--------------------| 
 |--------------------| 
 |---5----5----4------| 
 |---5----4----4------| 
 |--------------------| 
 |--------------------| 

You can subtitute the ii chord with other minor chords, the dominant chord with any other dominant, and the major with any other dominant, if its' a voicing that suits the melody.

      ii     V      I      
     Am11  Ab7b5  Gmaj6/9    
 |------------------------| 
 |----3-----3------4------| 
 |----5-----5------3------| 
 |----5-----4------3------| 
 |------------------------| 
 |----5-----4------3------| 

2-5-1-6

A7-D7-GMaj7-E7

I-iii-IV-V

Adding a minor to the I-IV-V progression.

C-Am-F-G
G-Em-C-D

See also