A key signature is a summary of the sharps or flats in a Major or it's relative Natural Minor scale. This series of lessons covers ALL 15 major and relative minor keys with their primary and secondary chords as well as sample common chord progressions.

In musical notation, a key signature is a collection of sharp or flat symbols placed together on the staff. Key signatures are generally written immediately after the clef at the beginning of a line of musical notation, although they can appear in other parts of a score, notably after a double barline.

Although a key signature may be written using any combination of sharp and flat symbols, about a dozen diatonic key signatures are by far the most common, and their use is assumed in much of this article. A piece scored using a single diatonic key signature and no accidentals contains notes of at most seven of the twelve pitch classes, which seven being determined by the particular key signature.

The key of C major-A minor.

Cover the primary and secondary chords and common chord progressions.