In Module 4, I introduced the idea of using a single scale to play over a chord progression, overlaying chord tones on the rectangle and stack as needed to target specific chords. In this module, we’ll explore a different approach: changing the scale to match each chord in the progression. One straightforward version of this is to play a major pentatonic scale over each major chord and a minor pentatonic scale over each minor chord, matching the root of each scale to the corresponding chord root.
This approach works well over many chord progressions, but in this module, we’ll focus on this one:
D - A - Bm - G
In Nashville notation (covered in Module 7), this is a I - V - vi - IV progression, which tells us that the progression is in the key of D major, and that all of the chord tones will fit the D major scale.
With the one-scale-per-chord approach, you would play the D major pentatonic scale over the D chord, the A major pentatonic scale over the A chord, the B minor pentatonic scale over the B minor chord, and the G major pentatonic scale over the G chord. It works in part because each of those four pentatonic scales is a 5-note subset of the 7-note D major scale.
Diatonic chords are chords that are created from an underlying scale, which means that every note in every diatonic chord is in the scale.
The major scale is built out of major second (whole-step) and minor-second (half-step/semitone) intervals.
Memorize this: The sequence of two- and one-fret intervals inside the major scale is an essential building block. It is also worth remembering how the interval names come from the scale degrees of the notes in the major scale:
Since the major scale repeats after seven notes, there are exactly seven different diatonic triads that can be created by starting on a scale degree, taking that note as the root, skipping one scale degree and selecting the next note as the third, and then skipping one more scale degree and selecting the next note as the fifth.
Memorize this: If you start on the first, fourth, or fifth scale degree of the major scale, you will build a major triad. You get a minor triad if you start on the second, third, or sixth scale degree. If you start on the seventh scale degree, you get a diminished triad.
Triad type Scale degree
(major scale)Interval spelling major 1, 4, 5 1 3 5 minor 2, 3, 6 1 b3 5 diminished 7 1 b3 b5
It’s also worth knowing these formulas for seventh chords, but you won’t need them for this course:
| Chord type | Scale degree (major scale) | Interval spelling |
|---|---|---|
| maj7 | 1, 4 | 1 3 5 7 |
| m7 | 2, 3, 6 | 1 b3 5 b7 |
| 7 | 5 | 1 3 5 b7 |
| m7b5 | 7 | 1 b3 b5 b7 |
There are six pentatonic scales hidden inside the major scale. You can build major pentatonic scales starting on the 1st, 4th, or 5th scale degrees of the major scale, and all the notes will come from the original major scale. Similarly, you can build minor pentatonic scales starting on the 2nd, 3rd, and 6th scale degrees.
This is why the one-scale-per-chord approach works so well: most of the music we listen to is built from the major scale or one of its modes, so these scales are right there inside the key.
It is worth understanding that these six scales are actually only three pairs of scales, with each pair sharing the exact same notes.
| Starting scale degree | Pentatonic scale type | Major scale degrees included |
|---|---|---|
| 1 | major | 1 2 3 5 6 |
| 6 | minor | 1 2 3 5 6 |
| 4 | major | 1 2 4 5 6 |
| 2 | minor | 1 2 4 5 6 |
| 5 | major | 2 3 5 6 7 |
| 3 | minor | 2 3 5 6 7 |
Memorize this: Because of the guitar’s tuning, these minor/major pairs of root notes line up on adjacent strings. Here, we use lowercase Roman numerals to indicate minor triads and uppercase numerals to indicate major triads:
We already know that we can play any of the minor/major pairs of scales using the same rectangle or stack shape and changing which note we treat as the root. The surprising and powerful consequence of this relationship is that all we have to do to switch scales on the fly is shift our rectangles and stacks up or down a string. We’ll explore that in sections 5-5 and 5-6.
In this module, your goal is to learn the positions of all of the G notes on the fretboard.
Exercises: Reuse the exercises from previous modules to memorize the positions of all the G notes on the fretboard. Don’t forget to mix things up to constantly challenge your memory.
We will practice changing scales for each chord in the D - A - Bm - G progression introduced earlier.
Exercise 1: Position your fingers anywhere on the fretboard and find a D note under them. Play the D note. Then visualize a D major pentatonic rectangle or stack that fits under your fingers. If the D note is under your index finger, use a stack; if it’s under your ring finger, use a rectangle. Then visualize how rectangles and stacks alternate vertically around it to create one of the five standard pentatonic forms. Then play some notes from that pattern. Keeping your hand in the same position, do the same thing with an A note and the A major pentatonic scale. Then do it again with a B note and the B minor pentatonic scale. Finally, do it with a G note and the G major pentatonic scale.
That’s one of the most challenging exercises in the module, but it’s really good practice for quickly finding root notes and constructing pentatonic scales around them.
Memorize this: The six pentatonic scales you need to play over most diatonic chord progressions are easily accessed by shifting a neutral-position scale (corresponding to the vi or I chord) up one string to play over a ii or IV chord or down one string to play over a iii or V chord.
For our example progression, the D chord is I, A is V, Bm is vi, and G is IV. That means that we can play both the D major and B minor pentatonic scales in the neutral position, and we will shift down a string to play the A major pentatonic scale and up a string to play the G major pentatonic scale.
In the key of D major, these are our shifts:
| Shift position | Minor chord/scale | Major chord/scale |
|---|---|---|
| shifted up | ii (Em) | IV (G) |
| neutral | vi (Bm) | I (D) |
| shifted down | iii (F#m) | V (A) |
Exercise 2: Shift a single rectangle through the progression. For each position, play the root of the chord/scale and then play all four of the notes in the shape. Start on any D note on the B or G string and visualize the appropriate rectangle or stack that falls under your fingers. Play the root and then the other notes of the shape. Shift the shape down one string set for the A chord and do the same. Shift back to neutral for the B minor chord and play the B root followed by the other notes of the shape. Finally, shift up a string set for the G chord, play the G and then the other notes.
Exercise 3: Repeat Exercise 2 using the stack shape.
Exercise 4: For each D note on the B and G strings, repeat Exercises 2 and 3.
Exercise 5: Repeat the process of the previous exercises, but only play notes on a single pair of strings. While you do this, visualize the rectangles and stacks shifting under your fingers as you change chords. Note that the root of the chord may not always fall on those two strings. In those cases, feel free to play the root on an adjacent string.
Exercise 6: Repeat the process of the previous exercises, starting on any D note and playing through the full six-string pentatonic pattern for each chord, emphasizing the roots as you go.
For any of these exercises, you can increase the level of difficulty by playing in time along with a metronome or backing track.
The difficulty step the line above describes: shift shapes in time with this click, and raise the tempo as the moves smooth out.
The goal of this section is to get comfortable applying the scale-shifting approach introduced in this module to improvising over a common chord progression.
Exercise 1: Choose a single D major rectangle that falls on the middle four strings of the guitar. In time with the backing track, practice creating a brief phrase on each chord, shifting the rectangle up or down as required and emphasizing one appropriate major or minor triad target note in each phrase. Don’t forget that you can bend the highest note of the rectangle up a whole step to reach the missing fifth pentatonic note.
Exercise 2: Repeat Exercise 1 using the stack shape. Your starting D root should be on the B or G string so that the full stack is always available, even when you shift.
Exercise 3: Expand from using a single rectangle or stack to using full six-string pentatonic patterns, staying in one position and shifting them up and down as you create short phrases for each chord. As this becomes more comfortable, begin to create phrases that smoothly transition from one chord to another. While doing this, practice emphasizing a chord tone on each chord transition and experiment with anticipating the chord change slightly.
Exercise 4: Expand from Exercise 3 and allow yourself to move around the fretboard using diagonal pathways and single-string navigation. This is a big step, but you have all the necessary tools to accomplish it.
I - V - vi - IV in D
D · 88 BPM · 4 chords · 21.8s loop
Here, the fretboard shifts to each chord's pentatonic scale as it arrives — neutral for D and Bm (I and vi), down a string set for A (V), up one for G (IV) — so your hand stays in one position. Drag across two chords to loop just that change, and feel free to slow down the tempo when you're starting out.