Welcome to micro study 3, the first part on the diminished 7 chord shape. Here one chord shape, a diminished 7, is shifted up and down the inner strings of the guitar. (Fingering suggestions are in the first few chord shapes.) The “melody” is based on the whole tone scale tetrachord (G# F# E D), with semi-tone approach notes to each one. The whole tone scale is a favourite of Villa-Lobos, in fact it is a style marker, and will appear again in this etude. And in later ones, so keep an eye out for it. All of this harmony is being contrasted against the low open E bass note.
Main points here are: