Keys / Family of Chords

Keys have been settled upon because the seven basic chords formed from the Major Scale 'sound good or like they belong together.' Consider these the key's 'Family of Chords.' For now, it's not essential to understand any more of exactly how they are formed, so if the above sounds complex just ignore it for now. Each of these chords have simply been assigned a Roman Numeral based on what the root (i.e. starting point or lowest note) of the chord is. Study the table below.

In this manner, the standard blues progression referred to earlier (the 'one, four, five' progression) is expressed as 'I - IV - V.' Thus from the chart above, we can see a typical blues progression in the key of D would consist of playing D, G and A chords (the I, IV and V chords of the key). Likewise, a common jazz progression is the 'ii-V-I Cadence.' Though it sounds complex, a ii-V-I in the key of C is simply Dmin, G then C. Again, simply refer to the chart above.

Prior to the advent of the Chord Wheel, extensive study and memorization was required to have this knowledge at your fingertips. Even then, should a number of months go by without exercising the knowledge the information slips away (as many degreed musicians can attest). Look instead at the legend printed in black and white at the upper-right of the Chord Wheel as well as the corresponding outline printed on the clear disc of the Chord Wheel.

Notice that the inner most circle consists of a given key's 'Major' chords (the I, IV and V) while the middle and outer circle contain the key's 'Minor' chords (the ii, iii, vi and vii). Align the clear disc in such a manner as the small arrow above the box labeled 'KEY' (and 'I chord') is pointing to the 'C' at the top center of the inner circle and colored light yellow. Once properly aligned, you have at your fingertips the key of 'C.'

Now you can plainly see that the 'IV chord' in the key of C is F Major. Should you wish to add a fourth note in the chord (i.e. a 'seventh' degree), the Chord Wheel prompts you to use a F Major 7 chord in this case. In the same manner, note that the 'V chord' (pronounced 'five chord') in the key of C is a G Major or a G7. As we discovered earlier, a G7 is also called a 'G dominant 7' which is a Major chord utilizing a 'seventh' degree that is a half-step/one note flatter than a Major 7th chord. (Once again, if this sounds complex just ignore it.) You may often see the chord referred to as a 'V7.' We know it's a 'major' chord because there is no small 'm' (a musician's abbreviation for 'minor') after the G and because the corresponding Roman numeral 'V' is a capital and not a small case 'v.'