A seventh chord contains a 1 - 3 - 5 just like a major chord, but also includes a flatted 7 note. So that would make it a 4-note chord. But you can also get the 7th sound from a 3-note chord by leaving out the 5, and just use the 1 - 3 - 7b. These are moveable for the C-A-G-E-D chords, so these chords can be formed all over the fretboard.
Task for this week is to learn the 7th chords from the 7th chord charts in the blues materials.
