This short module adds no new scales. Instead, it fills in two skills that the geometry of Module 3 let us postpone: finding notes by name, and reading the interval of any note at a glance. Together with the rectangle and stack, these form a complete navigation system, and everything in Module 5 builds on all three. The last lesson puts that system to work before we move on, pulling triad and seventh-chord arpeggios out of the same shapes.
Almost nothing in Module 3 required knowing the name of a single note. You started from a root location you already knew and used the geometry to find everything else. I call this dead reckoning, after the old navigation term, and it stays in your toolkit for the rest of the course.
There is a complementary approach that opens up a different kind of freedom: knowing specific notes by name well enough to jump directly to them, anywhere on the neck, without navigating from somewhere else first. I call that landmark navigation.
The good news is that you don't need all twelve notes to start using it. In most playing situations, there is only one note you actually need to find by name: the tonal center. Once that's under your fingers, the shapes you already know take care of everything else — including all the scales we haven't covered yet.
On a standard 22-fret guitar, there are twelve places to play almost any given note — two on each string. These positions aren't random. They form a repeating skeleton that works its way across the neck, and the skeleton is identical for every note. Only the starting position changes. It also repeats at the 12th fret, so once you know six positions, you know all twelve.
Memorize this: Every note's positions form the same repeating skeleton, which repeats itself starting at the 12th fret. Learn the skeleton once, and each new note is just a new starting position.
We've been working with this pattern all along. Every diagonal pathway and every in-position form in Module 3 was anchored to a specific root location inside its skeleton. Now we're going to learn to find those locations on demand.
The plan is simple: learn one note at a time. One well-learned note gives you immediate, practical benefit, and you don't need to master the entire fretboard before moving on. I suggest starting with A, then E, then D — those three cover the roots you'll meet most often in guitar-based music. From there, work through the other natural notes: G, B, C, and F. Save the sharps and flats for later.
While you're bootstrapping, you can find nearby notes by counting up the chromatic scale from a note you know. To find C# from A, count up four half steps: A#, B, C, C#. This adds extra steps, so you won't rely on it forever, but it's a good way to get started, and once you've found one location of your target note, the skeleton takes care of the rest.
For each note you work on, use several different practice approaches. That's what builds real recall rather than just recognition.
Exercise 4-1: The skeleton walk. Find the lowest instance of your chosen note on the fretboard and use the skeleton shape to work your way up, hitting every position as you go. Then reverse it — start high and come back down. This is the most direct way to learn the pattern.
Exercise 4-2: Combine note-finding with your scale work. Find any instance of the note you're practicing, build a rectangle or stack on it, and play through a scale exercise. Then slide to a different instance of the same root and do it again. This attaches the note-learning to something musical instead of a pure memory drill.
Exercise 4-3: Randomize. Pick a random position on the fretboard. Moving your hand as little as possible, find the nearest instance of your target note toward the nut, and then the nearest one toward the bridge. This is the hardest of the three, and it's the closest thing to what you'll actually need in a real playing situation. When you can do this reliably, you've really learned that note.
Practice one note per session and keep it focused. Rotation is fine; you don't have to spend a week on A before touching E. But don't try to do everything at once.
Knowing where the notes are is half the job. The other half is knowing what they are: the interval each nearby note represents relative to the tonal center. Once you can read those intervals on the fly, every chord voicing tells you what it's made of, and every scale in the rest of the course ties back to elements you already know.
We covered the interval naming system back in 2-1, so here is just the quick version. An interval is a distance measured in semitones, one semitone per fret, and each of the twelve distances has a name taken from the major scale. In shorthand, it's the numbers 1 through 7, and every number has a flat neighbor one fret below it, except for the root and the 4.
The rectangle and stack make identifying intervals easy. We already know how to connect the shapes across the entire fretboard, so if we learn the interval names in and around the shapes themselves, we can find the interval of any location on the neck.
Start with what you already know from Module 3. The roots live in fixed positions in the minor and major shapes. There's a 5 inside every pentatonic shape, always one string below the root. The major shapes contain a 3, and the minor shapes a ♭3. From there, the two scales diverge: the major pentatonic adds the 2 and the 6, and the minor pentatonic adds the 4 and the ♭7.
Memorize this: The interval of every note inside the minor and major rectangles and stacks. I don't usually recommend memorization, but this is well worth it.
Once you know the interval of every note inside the shapes, you can extend outward. All you need is the order of intervals in the chromatic scale. You know where the ♭3 lives in the minor rectangle; one fret higher is the 3, and one fret lower is the 2. You don't need a separate diagram for those, and you don't need to memorize them separately — you can infer them from the points you already know. Build outward from each known location, and you get a complete neighborhood containing all twelve intervals.
This is how you go from knowing five pentatonic intervals to being able to read any note on the fretboard in context. As an example, say I'm playing an A major barre chord at the 5th fret, and I want to know the interval of the note on the G string, treating A as the tonal center. I know there's an A at the 5th fret of the low E string, so I can place a major pentatonic stack there, build up through the rectangle above it into the next stack, and read the note directly: it's the 3.
I could just as well have used minor pentatonic shapes — the ♭3 is one semitone below the note in question, so counting up one gets me the same answer. Or I could have started from a different A entirely. No matter which path you take, you will always get the same answer.
One thing I really recommend is taking chord voicings you already know and working out what intervals they contain. For any major chord shape, you'll find only roots, 3s, and 5s; for any minor voicing, roots, ♭3s, and 5s. Seventh chords add one more note. Here's a movable seventh-chord voicing I like, with the root on the B string:
Exercise 4-4: Take a few chord voicings you already use, find the root inside each one, and work out the interval of every other note by building rectangles and stacks around the root. The chord names you've been using will start to make a lot more sense once you can see what's actually inside them.
You now have the third leg of the system. You know the rectangle and stack shapes, you know how to find roots by name, and you know how to identify any interval relative to those roots. Before Module 5 puts all three together on the major scale and its modes, 4-3 gives them a first job: reading chord tones straight out of the shapes.
So far the rectangle and stack have done one job: playing pentatonic scales. Later modules build a wide variety of other scales on top of them. They also give you arpeggios, without requiring you to learn any new shapes.
An arpeggio is the notes of a chord played one at a time. In 4-2 you learned to read the interval of every note in and around the rectangle and stack, so you already know where the chord tones are. The only work left is picking them out.
A minor triad consists of the root, the ♭3, and the 5, and all three live inside the minor shapes. In the minor stack, the root is the upper note on the middle string, the 5 sits directly below it on the same fret, and the ♭3 is on the top string, two frets toward the nut. In the minor rectangle, the root is the lower note on the upper string, the 5 is again directly below it, and the ♭3 is the other note on the upper string.
A major triad is the root, the 3, and the 5. These are the same shapes with a different root, exactly as in 3-8. In the major stack, the root is the lower note on the top string, the 5 is directly below it, and the 3 is on the bottom string at the upper fret. In the major rectangle, the root is the highest note, the 5 is directly below it, and the 3 is the other note on the lower string.
Memorize this: Triad locations in the minor rectangle and stack, and in the major rectangle and stack. In 4-2 I asked you to memorize the interval of every note inside the shapes, and this is the reason why.
You already know how to build an in-position shape by alternating rectangles and stacks. If you can do that, you can already play a two-octave arpeggio. You just skip the notes that aren't in the chord.
As you play these, don't think about an arpeggio shape. Think rectangle, stack, rectangle, and read the chord tones out of each one. Because you can build an in-position shape from any root on any string, this works from any root anywhere on the neck. When a shape crosses the warp, the chord tones shift with it, the same way the whole shape does.
Back in 3-5 we followed stacks diagonally. Every stack spans one octave, so a new stack starts where the old one ends, and for arpeggios that means every stack gives you one octave of the chord. In every stack, it is the same three notes in the same three places: 5, root, ♭3 for the minor triad, or 3, 5, root for the major. Slide up to the next stack and do it again.
Notice how the warp lands inside the top stack. The B and E string notes shift up a fret, and the chord tones come along for the ride. The second stack pathway, through the bottom of Form 3, the middle of Form 4, and the top of Form 5, works exactly the same way.
The rectangle pathway works too, with a bonus. Playing the scale along rectangles meant adding a connecting 4 between them, because a rectangle doesn't quite span an octave. The triad doesn't need it. Three of the four rectangle notes are chord tones, and the next rectangle picks up exactly an octave higher.
Everything so far has been triads, but the method works for most chords.1 If you can name the intervals, you can find the notes.
Take a dominant seventh: a major triad plus a ♭7. In 4-2 we found a ♭7 inside a seventh-chord voicing by going one fret above the 6, and the same move works here. In the major shapes, the 6 is one of the notes we've been skipping, and the ♭7 is one fret above it. That is one note outside the shape, so it's a little more to keep track of, but it's a small step on top of what you already know.
A minor seventh is a minor triad plus a ♭7, and the ♭7 is already inside the minor shapes, so you never have to leave the pentatonic. Diminished and augmented triads are one fret away as well: move the minor triad's 5 down a fret for diminished, or the major triad's 5 up a fret for augmented. Module 7 builds all of these chords properly, from the scale up. For now, the point is that any chord you can spell, you can play across the neck this way.
Exercise 4-5: Pick one chord, A minor or C major to begin with, and set up a drone on its root. Find every location of that root on the neck (there are twelve on a 22-fret guitar), build the in-position shape around each one, and play the two-octave arpeggio up and down. Don't skip the awkward positions. Where the rectangles and stacks sit across the warp or at the edge of the fretboard is exactly where the practice is needed.
Exercise 4-6: Pick a diagonal pathway and run the same arpeggio from the bottom of the neck to the top, stacks first and then rectangles. Start slowly, and say the interval names as you play them if that helps. The goal is to see the chord tones inside the shape, not to get through it quickly.
Exercise 4-7: When the triads feel steady, add the ♭7 and do the same thing with C7 or Am7.
Drone on the root. Change the chord to C for the major triad, and to C7 or Am7 for Exercise 4-7.
A2 · C3 ♭3
As always, treat these as starting points. Change the chord, change the pathway, change the direction, and make up your own variations.
The rectangle and stack show you what is inside a scale, and that includes its chords. You can find the roots by name, read the intervals around them, and pull chords out of the shapes. Module 5 applies all of that to the major scale and its modes.