3. They have the consonant notes of the major and minor scales;
4. The layout of the pentatonic scales on the guitar will form the backbone or skeleton over which everything else will either lie on top of, or relate to.
This last one is critical. It tells you that the rest of the stuff you learn is going to have scale fingerings that will relate right back to the fingerings in the pentatonic scale. KNOW THESE!!
The pentatonic scales, as the name implies, are five-tone scales. There are many different five-tone scales from all over the globe, but the scale we're concerned with here is Western in origin. The cool thing about the following scale is that it's like two scales in one. They are very similar to the traditional Major (Ionian) and Minor (Aeolian) scales that we hear and use every day. The difference is that the traditional Major and Minor scales have seven (7) notes per octave, and the pentatonic scales have five. Also, it can be both a major scale and a minor scale depending on how it's used. Now, uptight music theorists will tell you that the pentatonic scale is neither major nor minor, and they are correct, but it can also be both!!
If you look at the A minor/C major pentatonic scale (this means that this pentatonic scale can be played with either a minor or major emphasis), and looks at the A Minor (Aeolian) scale or the C Major (Ionian) scale to compare we see that two notes are missing from these scales in their pentatonic counterpart:
First you need to know that both A Minor (Aeolian) and C Major (Ionian) are related to one another. A Minor is the relative minor to C Major and C Major is the relative major to A Minor. This means that they both have the exact same notes in them. The difference is that A Minor starts on A, and C Major starts on C.
A Minor (Aeolian): A – B – C – D – E – F – G – A
C Major (Ionian): C – D – E – F – G – A – B – C
See how nicely they line up? They're really just the same group of notes with different starting points. This gives them such a different sound. **Heads up: when scales are relative to one another they share the same key signature as well.
Now back to the pentatonic scale.
A Minor (Aeolian):ABCDEFGA
A minor Pentatonic:A--CDE--GA
C Major (Ionian):CDEFGABC
C major Pentatonic:CDE--GA--C
Okay, notice that the B and F are missing in these pentatonic versions of the major and minor scales. It's removing these two notes that creates the pentatonic scale. When one is first learning to improvise, it's those two scale positions that cause the most frustration. You see, B and F are only one fret away from two of the strongest in notes in both C Major and A Minor. B is right next to C, and F is right next to E. These two notes help make the chord built off the root note in either scale. The notes B and F are only strong in very specific cases in the keys of C Major and A Minor, so when you land on them at the “wrong” time, they will sound BAD!! One has to be more familiar with how the scales function to make B and F work whenever they want to. Since I'm assuming that you're just starting out, I will assume that you're not so familiar and that the extra notes will cause you frustration. I had a very hard time with those two notes myself until I became more accomplished.
I chose these roots because if you look at the Circle of Fifths, one will see that C Major and its relative, A Minor, have no accidentals in their key signatures. This makes it easier to grasp the structure and use of the pentatonic scales (and other scales for that matter).
Good luck to you and your future guitar adventures!
