One of my favorite bluesmen, Scrapper Blackwell, headlines this course containing some of the greatest acoustic blues guitar pickers.

Blackwell is best known as the sidekick of Leroy Carr, the blues piano player. The combination of the two instruments in the hands of these two masters produced some of the most memorable classics of that time. Carr's 'How long Blues', for example, has become a blues standard included in many musician's repertoires.

His unusual guitar style was probably greatly influenced by piano music, which tends to be richer and more varied music than music produced by the relatively simpler guitar. His chord changes between verses tend to be more complex than is usual in standard blues structures and give his songs an unusual flavor.

Compare Scrapper's version of 'Nobody Knows You When You're Down and Out' with Clapton's version on his unplugged album to see what I mean. Eric's version passes from chord to chord in a progression that we would expect, but Blackwell slips in a chord now and again that just shouldn't be there. Interestingly enough, it doesn't grate. The fact is that we like clichés in our music - it's comfortable, we know where it's going before it gets there and we don't like it if that regular well-known pattern is changed too much.

This then is the heart of Blackwell's genius for me - he changes the regular chord structures, but not enough to spoil our listening pleasure and interest. It actually adds to the interest because it's embedded into the musical cliché we are familiar with.

The rest of the songs featured come from Leroy Carr, Blackwell's musical partner, and also includes:

• Pink Anderson
• Blind Willie McTell
• Willie Walker