1-3 · Fretboard Knowledge: The "Warp," Octaves, and the Minor Pentatonic Stack

Get the fretboard knowledge that makes the rest of the module click. You'll learn the movable octave shape (two strings and two frets up), then the "warp" — the dividing line between the G and B strings where standard tuning narrows to four frets, shifting any pattern that crosses it one fret toward the bridge. That sets up the minor pentatonic "stack": the compact six-note shape, well worth memorizing, that you'll picture and play all over the neck, with its root the higher note on the middle string.

If we start on any note on the E or A string and play a note that is two strings and two frets higher, that note is separated from the first note by exactly an octave.

This same shape works over most of the fretboard because most strings are separated by the equivalent of five frets. So, (2 strings) x (5 frets/string) = 10 frets, and then we add two more frets to make 12 for a full octave.

However, the G and B strings are only separated by four frets, and that difference warps the shape of any geometric pattern that crosses it. We can visualize this as an imaginary line that sits between the G and B strings:

The name warp comes from Jon Finn’s book Advanced Modern Rock Guitar Improvisation. He calls it the “warp refraction threshold,” but I shorten it to the warp.

Importantly, this octave move works just as well in reverse, to go down an octave.

The stack shape sits on three adjacent strings, each with two notes separated by two frets. Depending on which strings it sits on, it can look “normal” or appear in one of two different warped shapes:

The stack is the most powerful way to learn to play the pentatonic scale. There are five notes in the scale—four of them occur once in the pattern, and one occurs twice (the lowest and highest notes are an octave apart). When this shape represents the minor pentatonic scale, the root is the higher note on the middle string.