I have often heard young musicians who enjoy jazz music saying that they wish they could play jazz but there is too much to learn with all the theory and millions of scales and complicated chords. Dont you believe it! Sure, there are theorists and teachers out there who possibly try to impress by blinding students with their incredible knowledge and often only succeed in confusing them and scaring them off.
"Anyone can make the simple complicated. The secret is making the complicated simple."
- Charles Mingus
Take note of these words, they are very appropriate.
O.K so how does one learn to play jazz, to improvise over a chord progression? To play the various "standard chord progressions" and to learn to recognise them so that one can play all the jazz standards or perhaps something modern, maybe even your own compositions? I have read many books on the subject and have gone along to a series of lessons with a couple of guitar teachers and I have developed a few opinions of my own on the whole subject of playing jazz guitar.
Now comes the big statement! The whole thing about jazz being highly complicated and some sort of mystery that can only be unravelled with deep knowledge of endless theory is just not true. Jazz essentially, like all music, is basically pretty simple and you should strive to keep it so. Of course you need to have some knowledge, learn to listen, play within your limits, and have confidence in yourself.
First of all, I think all that stuff about modes and all the various fancy scales is overrated and a waste of time quite frankly. I have read many articles relating to or written by some of the guitar greats and they all kept things pretty simple and basically just played over chords. Their choice of passing tones and the phrasing and timing they used is what made the difference. I watched an instructional video of Joe Pass playing a concert and then holding a clinic and he said on there "don't ask me anything about modes 'cos I know nothing about that stuff". And I think he did all right, don't you?
Now having said that, there is nothing wrong with having knowledge about things like the modal system or whatever, on the contrary one can only develop from a foundation of knowledge, but I would have preferred it if the teachers had rather explained how the modes related to the major scale, which I think is far more relevant than just learning the scales in isolation. I mean if you are playing the major scale you are then playing all the modes anyway! To me there is nothing more damaging than learning scales and always playing up and down the scales as it could then become difficult to break away from just playing up and down endlessly without any phrasing (very often at breakneck speed with some players too!). So I think once you have learnt the modes and fancy scales, if you must, put them aside in your mind. Although, naturally one has to have command of the major and minor scales as apart from anything else all chords are built on that basis. Concentrate on learning songs. That's far more important and will benefit you in the long run.
Jazz improvising is basically about playing a melody over chords. So therefore one has to know chords. If you play on the notes of the relevant chord you are using the 1st, 3rd, 5th and 7th notes, so you're using 4 of the 7 notes in a scale. Then using whichever passing tones sound right to you, they will be probably the 2nd, 4th and 6th (more commonly thought of as the 9th, 11th, 13th) plus perhaps some chromatics , and using the phrasing that sounds right to you, then you're well on the way. Try to develop the habit of singing along as you solo, either the phrase or at least the timing. It is a huge help with the whole feel of what youre doing.
Another very important thing is, always think only about the most basic form of the chord when soloing. In other words, simply the major, minor or seventh forms of the chord, accentuating where possible the third and seventh notes of the chord. Don't ever try to think of the altered and extended form of the chords when you're playing a solo. You don't have the time to think about that and in any case the instument playing the harmonic background will be playing all the neccessary alterations and extensions to the chords.
The other thing is, when playing a solo, its all about tension and resolution. Learn which are the tension and resolution chords (the 1, 3 & 6 chords are resolution and can substitute for each other and the 2, 4, 5 & 7 are the tension chords and can substitute for each other), and of course whatever other substitute chords you know (e.g flat 5) which you might like to use. As always be guided by your ear when substituting. The chord you use to play over must not clash with the melody. The 5-1 cadence is the most important thing as it symbolizes tension and resolution and is an integral part of all music. So you can actually reduce all chords into just two categories i.e tension or resolution. The tension chords want to go somewhere, in other words to the resolution chord associated with it. By doing this you simplify the whole approach to constructing a solo.
As I said in the beginning, all of the above is purely my personal opinion of things and I'm sure lots of guitarists will disagree with me on certain or all of the points I have covered. Above all else though, have complete confidence in yourself and good playing to you all.
Music is your own experience and your thoughts...