Now a quick primer on chords for those of you who don't know what they are. Basically, if an instrument plays two notes or more from a scale simultaneously, it's playing a chord. Generally, people think of chords as consisting of three notes, the root note, the third, and the fifth. And in blues we also like to include the flatted seventh note to give it some extra blues character. In the next lecture, I will show you where the chord notes for the chords of the 12 bar blues are on the harmonica.