It is easier to understand musical key signatures when you know how to use the key signature chart. The chart is actually a collection of all the key signatures used in music sheets. There is a wide variety of charts available that illustrates musical key signatures but they all have the same function. They only differ in appearance. All you have to do is choose which one is the most applicable for your piano lessons.
We have learned that key signatures are the collection of sharps and flats used in every music sheet which usually appears in between the clef and the time signature. Therefore, the key signature chart shows us all of the different possible collection of sharps and flats with regards to the major and minor key. The only time these sharps and flats are not played is when a natural symbol appears before the note that falls on the line or space these sharps and flats are embedded on.
Unlike accidentals, which are the sharps and flats placed before a note, key signatures indicate all of the major and minor key to be played in flats and sharps throughout the music sheet. This means that a B-flat in a key signature implicates that all B’s should be played in a lowered pitch, without having to add any accidentals in every B-flat chord key.
Look at the key signature chart below, you will notice that only C major and (am) a minor are the only keys that do not have any sharps or flats in their key signature. All other major and minor keys have flats and sharps in their key signatures. Major keys appear on the treble clef and their relative minor keys appear on the bass clef. Both of these major and minor keys interrelate with one another in the key signature chart.
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Another way of illustrating the key signature chart is through the popular “Circle of the Fifths.” You will see the relationship of every major and minor keys here and it is often easier to memorize which sharp major and minor keys interrelate with other flat major and minor keys.