The Roadworks

It is particularly after dark that you find long stretches of road with all but one lane closed. People are working in the middle of the night in order to minimise disruption. It is a dirty job but somebody has got to do it.

Notes, Chords, Progressions

Progressions

Although the number of chords used in jazz is large, progressions of chords usually make up very predictable sequences. Jazz is much more tightly structured than most people think. In particular, there are a couple of basic building blocks that are so common that all jazz musicians know them. Far and away the most common building block is the 2-5-1 progression (pronounced "two five one"). If you are going to leave this site remembering only a single jazz-related term, then this is the one to go for.

The 2-5-1 derives its name from the scale modes it is built on. Let us call C "one". Which chord do you get if you start at C, and take every second white key on the piano within an octave? C major7, as we have already seen. Now move the C up one white key, call it "two", and repeat the procedure of taking every second white key within an octave. Which chord do you get now? D minor7. Finally, move the C up four white keys, call it "five", and repeat the procedure. Now you have a G7 chord. So by using the white keys only you can construct chords from all of the three main groups: major, minor, and dominant. Consequently, the D minor7 and the G7 are closely related to the C major7 even though they belong to different chord families. This is why the 2-5-1 can be regarded as a single building block.

In Autumn Leaves (mp3, pdf, tef) the melody starts with a 2-5-1 in major. Now compare this extract to the 2-5-1 progression on its own in clean and decorated form. This sound is very characteristic in jazz, and with a bit of practice you will be able to spot it miles away.

There is another kind of 2-5-1 progression that resolves to a minor key but it falls outside our simplified world view since it uses chords that are not strictly within the major-, minor-, and dominant groups. For the record, in D minor it is notated Em7b5-A7b9-Dm7. The b5 note in the first chord becomes the b9 in the dominant chord (never play the natural 9th on this chord!). In Autumn Leaves, the A section also contains such a 2-5-1 in minor.