Paul, I'm not an expert but I do tend to play more blues than most here, and by blues I'm including taking a blues(y) approach to tunes that may not necessarily be thought of as blues (ie. Standards, Pop, Rock, etc.). And of course, 'blues' comes in many forms, from the very primative (simplistic?) 'Mississippi Delta blues, to very sophisticated modern variations. There's (obviously ) a world of difference between B.B. King's 'The thrill is gone' and Monk's 'Round Midnight' but I consider them both 'blues'. But I digress. I don't want to get into what defines a particular song or playing style as 'blues', that would be way too subjective. But I think we would all agree that the one thing that all blues forms share is the ability to elicit strong emotions. Towards that end, I think that unless an artist has the ability to 'feel' and project those emotions outside of themselves, it will hard for them to give a convincing blues performance. Certain life experiences can make projecting these emotions (through music) either harder or easier. A look back at it's origins and at some of it's greatest players is a testament to that.

One thing that has not been stressed in this post is the importance of LISTENING. Blues is a case where the emotional is more important than the cerebral; where 'soul' outweighs technical skill or ability. LISTEN; listen intently to the (blues) artists that move you emotionally. Try to figure out WHY they move you like they do. See if you can incorporate those things into your own music and see if you can recreate the same kind of emotional response that they did. In the end, Blues is all about feeling. If you can feel it you can play it; conversely, if you don't or can't feel it, you will be hard pressed to produce a convincing blues performance. Chords are great, improv is great, feelings are great-er.

Just my .02 worth.

chas