Not having an easy-to-use, simple-sounding chord in that seventh spot of the key leaves a big harmonic gap to fill. Obviously, when things are more difficult to use in music, they don't get used as much as the easy stuff. It also doesn't work very well as a rock power chord (“root-5th-root”). Because the viiº chord is diminished, its flatted fifth can be too dissonant or unstable. In many styles of music, use of the viiº chord from the major key is rare. Other times it moves to the IV chord: C-B♭-F-C How the♭VII Chord Works Often, the ♭VII chord moves back to the I chord: C-B♭-C, or F-B♭-C The ♭VII chord appears in chord progressions in many ways. In the key of C major, a ♭VII chord would be B♭ (B♭-D-F) or B♭7 (B♭-D-F-A♭) borrowed from the parallel minor scale of C minor. And, sometimes, it causes heated debates. It is quite common, but it creates a lot of confusion and is easy to analyze incorrectly. While all of the borrowed chord possibilities do get used (including the i, iiº and v), most often you will encounter the minor iv, ♭III, ♭VI, and ♭VII chords borrowed from the parallel minor key.

The last common borrowed chord we will discuss in this lesson block is the ♭VII chord (“flat seven chord”).

B flat seventh chord guitar