Transposition

Transposition means moving a piece of music to a different key. Every note shifts by the same interval, so the shape stays identical - the same melody and the same chord relationships, just starting from a different home note. Musicians do this all the time, often to suit a singer's range or to make a part easier to play on a particular instrument.

Why it is easy

Once you know that each major scale produces the same pattern of chord qualities, transposing a progression is quick. Work out the Roman numerals in the original key, then apply them in the new one. Say a song is C - Am - F - G; in C major those are I - vi - IV - V. To move it to G major, find G's diatonic chords and apply the same numerals:

• G major scale: G, A, B, C, D, E, F♯
• I - vi - IV - V in G becomes: G - Em - C - D

So C - Am - F - G in C is exactly G - Em - C - D in G. The numerals carry the structure; only the letters change. This is the same key-relative thinking the Chords in a Key page uses, and it works for any progression in any key.