Following the changes

Most players learn one pentatonic box, find it works over a whole blues, and stop. It does work, in the sense that nothing you play will be wrong. It also means every bar sounds the same, because you are playing the key rather than the chord.

The alternative is to follow the changes: let the chord under you decide what you are aiming at. In a C blues the chords are C, F and G, and each one has a different note at its centre.

The target is the third

A triad is a root, a third and a fifth. The root tells you which chord it is and the fifth is nearly neutral, but the third is the note carrying the chord’s character. Land on it and the listener hears the chord, not the scale.

Read that third column again, because it is the whole argument. If you sit in C and keep aiming at the 3, you are aiming at E, which is right over the C and merely passable over the other two. The target moves and the box cannot tell you that.

The same hand position, two different chords

You do not have to chase the chords around the neck. Stand in one place and let them come to you: each chord has a shape near where you already are.

Approaching it

Landing straight on the third is fine. Sliding into it is better, and it is most of what makes a blues line sound played rather than typed. There are two notes a semitone away from any third: the one below, which is the minor third and the classic blue note, and the one above, which is the fourth. Both work, and the app marks them dashed because you pass through them rather than stop on them.

Where to stand

The five CAGED positions give you five regions, and every chord in the progression has a shape in each one. Learn the changes in one region until they are automatic, then move up and do it again. That is the drill, and it is why the tool asks you for a region rather than a chord shape when it is following a form.