Ok, Allow me to take this a step further. My "Book" shows me "5" shapes for Minor Pentatonic, 5 shapes for Major Pentonic, 5 shapes for Minor Blues, 5 shapes for Major Blues & etc. Each shape is shown with its own ROOT. The Root is in or ON a different note in each shape and yet I'm told that each shape is moveable. But it mentions no LIMITS on where the shape can be moved or cannot. Shape ONE on MINOR shows the ROOT on the 6th string and again on the 4th and again on the 1st string, shape two on MINOR Penta shows the ROOT on 4th string and the 2nd string. Shape 3 etc. Then I'm told that I can move any (or one) shape up and down the fretboard as long as I start on the ROOT of the scale on either the 6th or 5th string. OK, I jump on over to SHAPE 2 MINOR PENTA and lo and behold the ROOT is pictured on the 4th string. What do I do about the BLACK dots on strings 6 and 5? Confused? I am totally. If it's movable why do I need 5 shapes? Thanks for your patience. Nick
I think I might see where you are confused. Let me see if I can explain.
Each shape is moveable. What that means is that you can move a given shape up or down the fret board so the first position or first note played (the root note) starts on a different pitched root. If the root note is first played on the 6th string and you have 22 frets - you can play a given shape in 15 or so different places on the fretboard (depending on how many frets the shape spans and in which direction from the root the shape goes next). Each different starting point is a different root for a different scale (A B C D E F G plus sharp or flat roots).
The fret you start on tells you the root (and accordingly which scale A B C etc. you are playing). So using shapes that start with a root note played on the 6th string (Low E String = fattest string) as an example - if you start the shape on the fifth fret of the low E string, the root note is A and the scale is the A something scale (A Major Pentatonic, A Minor, A Blues etc.).
If you MOVE that shape to the 7th fret and play it exactly the same way (same shape only moved) - you will be playing the B something scale (because you are now starting on B making B the root note). So the name of the scale you are playing with a given shape will change each time you move it to start on a different fret. Got it?
So why are there 5 different shapes?
First - let me explain why the root note occurs in several different places in each shape in each scale. All scales start on the root note and if played in ascending order - can be and usually are, carried to the root one octave higher. For scale shapes starting on the 6th string (low E) each shape can span up to three octaves meaning the root note may appear 3 times in the shape.
Now for the reason you need 5 shapes. The guitar is different from a keyboard instrument such as a piano in that there are many different places on the guitar fretboard that you can play the exact same note at the same pitch (on a different string). On a piano, there is only one place to play any given pitch. Also on guitar, every time you move 12 frets on any given string (up or down) you play the same note - except in a different octave.
So there are multiple places on the fretboard where you can play an A for example. Depending on where you play the A - if you use that as a starting point to play an A Minor Pentatonic scale (for example), you will usually have at least two different directions you could go to get from A to the next note in the scale (C if playing A Minor Pentatonic).
So if you start on 6th string 5th fret A - you can go to the next note C by playing it on the 5th string 3rd fret. From there there you will go to the D on the 5th string 5th fret and so on. Let's call that shape one. Alternatively you could start in the same place (6th string 5th fret A) and go to the next note C by playing it on the 6th string 8th fret. If you start in that direction you will be playing a different shape (you might call it shape 2). You might choose shape 2 if you wanted to ascend the scale to reach some higher notes in your solo.
So what about the other shapes? Why 5? If you start your A Minor Pentatonic scale on the A found on the 12th fret of the 5th string (A string) you may find it easier to play the scale from there with one of the other five shapes.
You don't have to learn all five shapes in the beginning! You might want to start by learning the two most common shapes for each type scale. Then you will be able to move either of those shapes to play the corresponding scale (Major Pentatonic/Minor Pentatonic/Whatever) in whatever key fits the song you are playing along with - by moving that moveable shape to start on a different fret and thus starting with a different root and thereby making it a different scale (ie. A something scale, B something scale, etc. depending on where you choose to play the root of the shape).
Later you can learn another shape and then another to give yourself more options and more versatility. Regardless of where you start to play a particular scale on the guitar, the actual notes of the scale are the same. But because there is usually more than one place to play each of the notes, certain shapes are more practical given certain starting points and desired ending points.
So the shape that is most appropriate or easiest to play (for normal folks with normal length fingers) will depend on where you start to play the scale and where you want to go from the starting point. Where you start, will depend on how you want the notes you plan to play to fit in with the song or piece and what type of feel you want to impart.
I hope this will help you understand movable scale shapes better.
Have fun as you improve your guitar playing skills. It's a lifelong journey - enjoy every minute of it!