The Other Pentatonic Diagonal

In all of my previous lessons on the pentatonic scale, I missed one potentially useful way of navigating the fretboard. This brief PDF lesson is my attempt to address my oversight.

The other pentatonic diagonal

When I originally released the video “The ONLY pentatonic scale lesson you will EVER need (yes, really)” on YouTube, I honestly meant those words in the thumbnail image. At the time, that video captured all of my insights into the pentatonic scale. There’s a lot of powerful stuff in there, but, of course, there’s always more to the story.

In the original video, I demonstrated how rectangle and stack shapes can be alternated vertically to recreate the five standard pentatonic fingering patterns, and I explained how stacks connect diagonally to form highly useful pathways. I also showed two ways to think about horizontal movement.

But I missed some valuable insights. I didn’t discuss diagonal rectangle pathways, which turned out to be quite useful for playing three-octave arpeggio and scale patterns. I didn’t present what I now consider to be the best methods for navigating horizontally (namely, this one-string method and this two-string method).

With those extensions, I thought I had covered all of the valuable approaches, but I still managed to miss one (and there are probably still more to discover).

Pilotage vs dead reckoning

There are two basic types of navigation. Pilotage is navigation using visible landmarks. Finding a position on the fretboard using fret markers is an example of pilotage. Memorizing the notes of the fretboard enables you to use pilotage to play scales anywhere on the fretboard. You find a root, place a rectangle or stack around it, and fill in additional scale notes as needed (and you can play almost any scale with this approach).

The second basic type of navigation is dead reckoning, in which you determine your position by reference to a known starting point. Shifting from a stack to a neighboring rectangle without referring to fret markers is an example of dead reckoning. Pentatonic gear shifts are another example—using one scale’s position to find the position of a related scale.

Dead reckoning is much faster than pilotage, so it’s valuable to have multiple strategies for doing dead reckoning on the fretboard. The missing diagonal is another dead reckoning strategy to add to your toolkit.

This missing diagonal

In previous lessons, I have covered vertical, horizontal, and diagonal navigation using rectangles and stacks, but I only covered diagonal moves that go toward higher strings and the bridge (or, conversely, toward lower strings and the nut). In my diagrams, these are oriented like a forward slash (/). These are the moves most commonly used by professional players, so they were the most obvious ones to teach.

But it’s also pretty easy to use the other diagonal (toward higher strings and the nut). On an all-fourths fretboard, you can shift up one octave by moving up three strings and down three frets. Conversely, you can shift down an octave by moving down three strings and up three frets.

For the stack, the resulting diagonal pattern looks like this:

The key relationship to remember is the major third (one string up, one fret down) between the corners of the stacks.

This reverse stack diagonal shows up in three different ways on a standard-tuning fretboard. These examples are in G major pentatonic (or, equivalently, E minor pentatonic). As always, watch out for the effect of the warp:

These relationships are relatively easy to play, although it can sometimes be helpful to add one of the invisible trapezoids that fit between vertically stacked rectangles and stacks, like this:

or this:

For completeness’s sake, it’s worth noting that there is a similar diagonal for rectangles:

This one is less useful in practice because of the two-string gap between rectangles. As with the stack, this pattern shows up in three ways on a standard-tuning fretboard:

When trying to navigate rectangles this way, I found it’s easiest to visualize the missing stacks as connectors, so I don’t tend to use it in practice.

Conclusion

In my opinion, it’s worth learning the reverse stack diagonal. They’re pretty easy to connect smoothly, and they allow you to go up an octave without moving toward the bridge. This comes in handy, especially on acoustic guitars where access to the upper frets is limited.

To get the patterns under your fingers, I recommend practicing playing up and down the pentatonic scale in threes. Here’s an example that ascends the E minor pentatonic scale (using the fingerings from the first G major stack diagram shown earlier):

And here’s a descending example based on the third G major stack diagram shown above:

When playing these, pay close attention to the sequence of positions used to navigate the jump from one stack to another. Since the two neighboring stacks share one note, you always have a choice when playing that note. I think the fingerings shown in the examples are the easiest to play, but if you find another fingering you like better, go for it!