Home : Theory and Patterns : Chord Substitution and Reharmonization
Here are the basic chord substitution rules:

1) Substitute vi and/or iii for I
2) Substitute ii for IV
3) Precede any unaltered dominant chord with a minor chord on the root note a fifth above (i.e., precede G7 with dm).  This is called the "ii V" substitution.
4) Precede any chord with the dominant chord a fifth above (i.e., precede G7 with D7).  This is called "back-cycling".
5) When back cycling to a minor chord, the dominant chord should be altered with a #5, b5, #9, or b9 (i.e., precede dm with A7b9)
6) When using a ii V substitution for an altered dominant chord, use a m7b5 chord for the ii substitution (i.e., precede A7b9 with Em7b5).
7) Remove the root note from any 7b9 chord, and what's left is a diminished 7th chord, which you can move up or down 3 consecutive frets (i.e., A7b9 is the same as Bbdim7, C#dim7, Edim7, and Gdim7).
8) Use a tritone (b5) root note substitution for any dominant chord (i.e., replace G7 with Db7).  These chords contain the same 3rd and b7th intervals.
9) Extensions, especially 7ths, 9ths, and 13ths can be added to just about any basic triad or 7th chord (i.e., Cmaj9 can replace Cmaj7).
10) Alterations can most often be added to dominant chords:  #5, b5, b9, #9, sus, etc. (i.e., G7#5 can be played in many cases, instead of G7)

In most song harmonization situations, you typically start with a basic I IV V harmonization of the melody, add some vi ii and iii root note substitutions, backcycle to add new harmonies, add some ii-V and tritone substitutions, and extend/alter the chords in the final progression (the diminished chord is simply a 7b9 extention/alteration).

Jingle Bells:

C            | Em          | Am          | C           | F           | C               | Dm        | G7     |

C            | E7          | Am          | C    C7     | F    Dm     | C    A7         | D7        | G7     |

C     E7     | Am   A7     | Dm   G7     | C    C7     | F    Dm     | C E7 A7         | D7        | G7     |

Cmaj9 E7(b9) | Am7  A7(b9) | Dm7  G7(#5) | Cmaj7 C9    | Fmaj7 Dm9   | Cmaj9 E7 A7(b5) | Dm D7 Ab7 | G7 Db9 |

Happy Birthday:

| C       | G            | G         | C            | C           | F        | C  C  G  | C |

| C Am Dm | G Em A7b9    | Dm G7 Db7 | C Em D7b9    | Gm C7 C#dim | F Dm Db7 | Am D7 G7 | C |

| C Am Dm | G Em7b5 A7b9 | Dm G7 Db7 | C Am7b5 D7b9 | Gm C7 C#dim | F Dm Db7 | Am D7 G7 | C |

| I iii vi | V V7 bIIdim7 | ii V7 V7#5 | I ii V7 | I I7 I7#5 | IV ii iv | iii vi V | I |

Have Yourself a Merry Little Christmas:

C         | G      | C       | G        | C       | F       | C        | F         | G      | C

C     Am  | Dm  G  | Em A7b9 | Dm  G    | Em      | Dm      | Am  C7   | F         | G7     | C

Cmaj7 Am7 | Dm9 G7 | Em7 D#7 | Dm7 Db13 | Em A7b9 | Dm Fdim | Am7 C7#5 | Fmaj7 Dm7 | G#9 G9 | Cmaj9

| Cmaj7 Am7 | Dm9 G7 | Em7 D#7 | Dm7 Db13 | Cma7 Am7 | Dm7     | E7 A7 | D7 G7 |

| Cmaj7 Am7 | Dm9 G7 | Em7 D#7 | Dm7 Db13 | Cma7 Am7 | Dm7  E7 | Am    | C7    |

| Fmaj7 Fm  | Em7 Cdim7 | Dm G7#5 | Em E7b9 | Am B7b9 | Em G7#5 | Em  D7 | G7sus4 Db9 |    

| Cmaj7 Am7 | Dm9 G7 | Em7 D#7 | Dm7 Db13 | Em A7b9 | Dm Fdim | Am7 C7#5 | Fmaj7 Dm7 | G#9 G9 |

| Cmaj9 Am7 | Dm Db7 | C |

Jingle Bells Substitutions:

I                          IV     I        V      V
C    C     C     C         F      C        G      G         I IV V
           Am                 Dm      Am  (Em)              Diatonic Subs

     E7              C7             E7  A7 D7    G7         Back Cycle

                 Gm    Gb7                 (Am)     Db7     ii-V,  Tritone

CM7  E7b9  Am7   Gm9 C9 Gb7   Fmaj9 E7b9 A7                 Extended Chords 
CM9  Fdim7     D7#5        Dm         Am9  D9    G7         (7b9 or dim -> min)
     G#dim7    Ab7

CM7 CM9 | E7b9  Fdim G#dim Bdim | Am7 Ab7 | Gm9  C9(Gb7) | F(add9) Dm7 | CM7 E7b9 Am9 A9 | D9 | G7 Db9 |

Georgia on my Mind:

C           E7          Am         Dm   G7        C    A7    Dm   G7

    Em7(F#7)Bm9   E7 Bb7     A7(b9)   D7   Db7      EmE7  A7#5  Db7 G7#5
        C9                   Bbdim7

Silent Night:

C      C      G7     C       F       C       F6    C     G7     C        C   G7     CM9
   Em  Am  C                   Dm G7   Gm9 C7(D7 G7)Am D7  G7b9 Am F#m7b5  D7  Db7b9
         A7b9 Dm  G7     C7                    Ab7    D#dimG#dim
         Bbdim                                             Bdim

Amazing Grace:

C        F        C     C     G     C       F     C       C  G    C


Copyright 2004-2013 Nick Antonaccio, all rights reserved.