So, now that you're hooked, what about the actual reality?
The twelve bars refers to a musical term called measure, measures are informally referred to as bars, which is how the notation looks. It looks like vertical bars, and with the twelve bar blues progression, there are twelve. When you marvel at your favorite blues artist and how they do all that wonderful stuff, just remember that it is simplicity itself, and it is only one layer atop the other that gives the depth style and rhythm that you hear.

The progression part is the chord changes, and the blues part is the style. There are only three chords in blues and they are called seventh chords. The blues chords are A7, B7, and E7, and again, all the fancy stuff that you love so much is only technique and personal style in combination with those three basic chords. The actual blues style is to sing a line, and then repeat it, followed by additional lyrics that tell the story.

The first line has that all too familiar, “Woke up this mornin' start followed by the situation, Like “Woke up this morning”, and I couldn't feel my head. Said I woke up this mornin', and I couldn't feel my head”. Then the next line describes why he is this way – “I know I lived through last night, and that's why I feel half dead”. The pattern is repeated in the second verse.

As far as the playing goes, there are as many styles out there as stars in the sky, but what you are listening to is called a riff. A riff is a certain way of playing that sets this player apart from the others. A riff can also be called a lick. This is what the artist has learned from others on the way up, and eventually made his own. It is best not to try to figure out the fancy playing, and why it is this way or that, it is always best just to allow yourself to feel, as all the greats have.

It is easy to get lost in all the technical jargon of dominant sevenths and tonics, to sub-dominants, etc. The best advice is to either mentor with someone who knows, learning as you go, or take lessons from a qualified instructor. It is crucial that you get off on the right foot. If you don't. Then it is easier and easier time to lose interest, and eventually give it up, because you start to think that being good is for someone else, but not for you.

So, remember to keep it simple, that's what the blues is all about and that's where you'll get your enjoyment.