Chord Numbers
When transposing chords, a similar system can be used. Most of the chords you have been using so far are built on the root notes C, F and G. These correspond with the first, fourth and fifth notes of the C major scale. These three chords are therefore referred to as chords I, IV and V in the key of C. Chord numbers are almost always shown in roman numerals.
The chord numbers remain the same regardless of the chord type. E.g., the chord I shown previously could be a C major, C minor or a C7. It will still be described as chord I as long as it is built on a C root note. To transpose these chords to the key of G, you would simply find the same chord types built on the first, fourth and fifth notes of the G major scale as shown.
This example shows a chord progression using chords I, IV, V as 7ths in the key
Here is the same progression transposed to the key of G.
Here are some more piano parts in the key of G. Try transposing them back to C.
Here is a 12 Bar Blues piano part in the key of G. Once you have learned it, try transposing it to the key of C.
By now you should be getting familiar with transposing between the keys of C and G. The next step is to try a new key, e.g., F. All you need to know are the scale degrees for the F major scale and you are on your way. Playing in all keys is discussed in detail in the book Progressive Funk and R&B Piano Technique.
