Did you know that you can play a melody starting on any of the twelve possible notes, while still preserving its melodic and harmonic character?
For example, you can play “Twinkle, Twinkle” starting on the note C…

But you can also play starting on the note G.

or starting on the note Eb…

In fact, you can play “Twinkle, Twinkle” (or any other melody) starting on any of the twelve physical keys on the piano.
Special Note: In this example the very first note just happens to be the key center Do, but this is not necessarily so.
How Many Keys are There?
Since there are twelve possible physical keys on the piano, there are twelve possible physical “keys” in which you can play a piece of music.
But, while there are twelve physical keys, it is possible to write music with no sharps or flats or up to seven sharps or seven flats in the key signature, making at least fifteen keys theoretically possible.
That said, here is “Twinkle, Twinkle” written out in all fifteen theoretical keys…
C# Major…

F# Major…

B Major…

E Major…

A Major…

D Major…

G Major…

C Major…

F Major…

Bb Major…

Eb Major…

Ab Major…

Db Major…

Gb Major…

Cb Major…

Read and play the fifteen scores above and notice that…
- Do always sounds and feels like Do, So always sounds and feels like So, La always sounds and feels like La, and so on… no matter what key you are in!
- When you change keys, all the letter names of the notes change, but the Solfege names remain exactly the same. The letter names change because they are arbitrary, but the Solfege names remain the same because they represent the inherent melodic-harmonic function of each melody note, which remains the same no matter what key you are in.
Understanding these concepts is essential for understanding how scales and melodies work, laying a solid foundation that facilitates ear training, music reading, memorization, and advanced skills such as transposition.