How do you know in what key a song is written? A guitar playing worship leader loves certain keys because of the chords that are used in that key. But what does the key mean?
If you play a song in the key of C for example. The song is based on the C scale (CDEFGABC) which has no sharps or flats. So every song is based on a scale of 8 consecutive notes . Then every scale has 3 basic chords based on the tones on that scale. The 3 basic chords are the I chord (CEG) and the IV chord (FAC) and the V chord (GBD). Technically you could play any song with these 3 basic chords. The roman numerals refer to the tone of the scale from which you start to build the chord. I=1st tone of scale. IV=4th tone of the scale. V=the 5th tone of the scale.
The following are common keys to play with their scales and chords.
- Key of C based on the C scale (CDEFGABC) and C, F and G chords.
- Key of D based on D scale (DEF#GABC#D) and chords D,G and A
- Key of E based on E scale (EF#G#ABC#D#E) and Chords E,A and B
- Key of F based on F scale (FGABbCDEF) and chords F,Bb,C
- Key of G based on G scale (GABCDEF#G) and chords G,C,D
- Key of A based on A scale (ABC#DEF#G#A) and chords A,D, E
As you can see, the scale determines the number of sharps or flats used and will be reflected in the key signature at the beginning of the piano music. A key signature tells the musician which notes to sharp or flat when playing the song. The music doesn’t have to print every sharp (raise 1/2 step) or flat (lower 1/2 step) within the music.
This also reveals why it’s more difficult for a piano player to play the key of E (with 4 sharps) than a guitar player (who thinks chords not notes) . Guitar players usually avoid flats and piano usually prefers flats to sharps. Thus the constant turmoil in a worship team to stretch players without frustrating them. But then thank goodness there’s always the capo!
For more theory, check these: