Introduction to Position IX
Rondo on p. 252 has one brief passage in Position X which is really part of five-fret scale form from Position IX. To understnd, first learn new notes at fret XII which are accessed by your 4th finger. Like the V and X fret notes, these are all natural (and all are an octave higher than open strings).
Practice saying and playing:
The diagram to the right shows all the natural notes in Position IX. All five major scale forms in standard guitar keys (C, G, D, A, E major) are available in this position Complete study materials with prep—scales, triads, and scale challenges—plus 14 inventions are available as a free .pdf download at the Book III Online Media.