The CAGED cycle - Position

There are five open chord shapes every guitarist learns first: C, A, G, E and D. Move any one of them up the neck and barre what the nut was holding, and it is still that shape, just naming a different chord. Five shapes, and between them they cover the whole neck for any chord you like. That is the entire system.

The five shapes for one chord

Take C major. The C shape sits at the nut, and the same chord turns up again as an A shape at the third fret, a G shape at the fifth, an E shape at the eighth and a D shape at the tenth. Five ways to play one chord, spread along the neck.

Every C major chord tone on the neck, coloured by the shape that frets it. The bars underneath show where each shape sits. Where two colours split a dot, both shapes are holding that note down.

The order never changes

Going up the neck the shapes always appear in the order C, A, G, E, D, and then C again an octave higher. It never breaks and it never reorders. What changes between keys is only where you enter the loop.

Key	Going up the neck
C	C at 0, A at 3, G at 5, E at 8, D at 10
A	A at 0, G at 2, E at 5, D at 7, C at 9
F	E at 1, D at 3, C at 5, A at 8, G at 10
B	A at 2, G at 4, E at 7, D at 9, C at 11

Read those rows across and they are all the same sequence, started at a different letter. F begins at E and wraps round to G; B begins at A. This holds in all twelve keys, and the app relies on it: the shape chips are simply sorted by fret, and that sort always walks the cycle.

The shapes overlap, and that is the useful part

Neighbouring shapes share notes. In A major the A and G shapes both hold three notes at the second fret, the G and E shapes share the fifth, the E and D shapes share the seventh. Those shared notes are the seam: they are where you cross from one box to the next without lifting your hand off the neck.

A major. The split dots are the seams between neighbouring shapes.

In minor

The geometry is identical. Every major third drops a semitone to become a minor third and the rest of the shape stays exactly where it was. The C and G forms lose their third off the top of the shape when you do this, so those two strings take the fifth instead, which is why the minor C and G forms look like stretches. The order, the positions and the seams are all unchanged.

A minor, E shape at the fifth fret, with the minor pentatonic around it. Filled dot is the root; thick ring is a note the shape is holding down.