3-7 · Horizontal Pentatonic Movement 2: Two-String Shapes and Melodic Sequences

Single-string playing gives you long-range mobility, but you only ever have two notes under your fingers. Two adjacent strings double that, and four notes is enough for real melodic sequences while keeping the neck just as easy to travel.

Put the minor pentatonic scale on any pair of adjacent strings, and you get five distinct box shapes. Each holds four notes, they appear in a fixed order, and together they tile the entire fretboard. Nothing here is new; it is the same geometry viewed a different way.

Take the D and G strings, which sit clear of the warp. The familiar three-fret rectangle is there. On either side of it are halves of stacks: the lower half of a stack below it, and the upper half of another above it. That leaves two shapes we haven't met, which I call the lower and upper trapezoids. In the in-position patterns, they are what sit in the transitions between rectangles and stacks.

Finding the root is easy. It is still the lower note on the upper string of the rectangle, and that same note is the highest note in the lower stack. The other root sits inside the upper stack, and is also the lowest note in the lower trapezoid. Taking each string on its own, both are the upper note of the isolated two-fret span, exactly as we would expect.

Across the warp, you get the same five shapes with the geometry shifted by a fret, exactly as it shifts for the full rectangles and stacks.

Exercise 3-9: Pick two adjacent strings and a root, set up a drone, and play inside one shape for a while. Then shift up or down to the next shape in the sequence and play those notes. The goal here is only to learn the order of the shapes and keep track of where you are in the scale.

Sequences

Four notes per shape is enough for a real melodic sequence. Choose a pattern inside one shape, play it, shift to the next shape, and play the same pattern there. The sequence carries itself along the neck. This is the idea from 3-4, but the shifting is easier to see and much simpler for the hands.

Starting from the second-lowest note of each shape instead gives a similar result with a different feel, and both are worth practicing. So are the two descending versions. You can also use all four notes.

More interesting still is to make the internal motion and the lateral motion work against each other, playing a descending pattern while moving up the neck, or an ascending one while moving down.

Longer patterns are worth experimenting with. They tend to sound more complicated and harder to play than they actually are, which is probably why they turn up so often in rock solos.

Memorizing these as a list would miss the point. The principle is the thing: take any pattern and apply it to each shape in turn. Once your fingers know the shapes, you can invent sequences on the spot with much more variety than any fixed list could give you. Get comfortable with one, then change it the next day.

Exercise 3-10: Start with one pair of strings and one key, and learn the five shapes in order, ascending and descending, before worrying about sequences. Then add a simple three- or four-note sequence and apply it to several shapes in succession, aiming for consistency rather than speed. Move to another pair of strings and notice how the shapes look different across the warp while remaining the same five shapes. Then spend part of each session combining two-string movement with single-string, in-position, and diagonal playing, which matters more than perfecting any one of them on its own. Always use a drone or a backing track, bending the ♭3 slightly over a major drone and letting it sit over a minor one. And invent your own sequences rather than just replaying mine.

Everything in this module has been the same scale and the same geometry approached four ways: in position for a vertical view, diagonally for an oblique path, one string for horizontal movement a note at a time, and two strings for horizontal movement with enough notes for real phrases. None is more fundamental than the others, and the goal is not to keep switching for its own sake, since you may well spend a whole solo in one position. It is to have the options, so you can follow your ear instead of feeling "stuck in a box."