The 2 5 1 Progression
Once you know how to play over scale tone 7th chords, the next step is to improvise over chord progressions which contain these chord types. One of the most common progressions used in Jazz is the 2 5 1 progression.
As the name implies, this progression begins on the second chord in the key (2m7), progresses to the fifth (57) and then progresses to the chord which the key is named from ( 1maj7). A good way to become familiar with this (or any) progression is to have a friend play the chords on keyboard or guitar, or use a play-along CD and play the arpeggios of the chords over the backing. The example below shows this procedure in the key of C. Learn it in this key and then transpose it to all the other keys.
Once you are comfortable running through the arpeggios against the chords, try improvising with the arpeggios as shown here. Once again, learn this example and then transpose it to all keys. As stated earlier, this process is essential if you wish to become a good player. You should now be doing it as a matter of course with everything you learn.
Don’t forget to run through the appropriate modes for the progression and then improvising with them. This example demonstrates a line derived from the D Dorian, G Mixolydian and C Ionian modes, being conscious of chord tones at each change.
1 Becomes 2
There are many Jazz standards where a 2 5 1 progression is followed by another 2 5 1 progression in a key whose i chord is a tone (major 2nd) lower. In this situation, chord 1Maj7 of the first key becomes chord 2min7 of the next key.
This means that if you are improvising over the progression, all you have to do is change the chord from a Major 7th to a minor 7th by lowering the 3rd and 7th degrees a semitone. Here is an example.
To help you become more familiar with this type of change, it is a good idea to practice alternating between a Maj7 and a min7 chord on the same root note with arpeggios, modes, and improvised lines as shown below.
Once you are comfortable alternating between the two chord types, the next step is to repeat the process through all the keys. Try progressing down a semitone until you reach the same note an octave lower, then go up by semitones, then around the key cycle both ways, up and down in major 2nds, minor 3rds and major 3rds.
5 Becomes 2
Another common situation is where you have a 2 5 progression which does not progress to 1, but in the next bar, the 57 chord becomes 2 min7 of the next key. In this case, all you have to do is lower the 3rd of the chord by a semitone to change from a dominant 7th to a minor 7th. Here is an example.
As with the change between the Major 7 and minor 7 chords, practice alternating between a Dominant 7 and a min7 chord on the same root note with arpeggios, modes, and improvised lines as shown here.
As always, the next step is to repeat the process through all the keys. Try progressing down a semitone until you reach the same note an octave lower, then go up by semitones, then around the key cycle both ways, up and down in major 2nds, minor 3rds and major 3rds.
It is also common for 2 5 1 progressions to occur over two bars rather than four. As with the four bar version, practice running through the arpeggios and modes and then improvising with them. Remember to do this in all keys. When you find a pattern you like, play it around the cycle without stopping as shown here. Then play it around the cycle in the other direction, then up and down chromatically through the keys and up and down through various interval cycles.
