Years ago, I came across an article on a Spanish site guitarra.artepulsado.com posted by Oscar López who had taken notes during a summer course with the great Cuban composer and guitarist, Leo Brouwer. The title of the post was Axiomas básicos de Leo Brouwer. I found the word file and thought I’d translate it for all non-Spanish speakers. It provides a wealth of advice. I’ve added a few commentaries below to expand the ideas a bit. Hope they are helpful.

Warm Up

Use chromatic octaves for the left hand and arpeggios and rasgueados for the right hand. Play close to the body in higher resonant positions upon starting your practice.

*I think this may mean to start your practice without having the left hand in an extended position. Starting in higher positions is less stressful for the left hand.

Speed and Scales

Use fixed, non-shifting positions in the left hand that are close to the body (i.e. higher positions) to play short bursts of notes. Play bursts in short crescendos (soft to loud or light to intense). Start on one string, then expand to two strings. Add one note at a time and pause between each mini-scale.

Add color and articulations to scales.

Left Hand Shifting

Left-hand notes should be played staccato (*perhaps he means before a shift). Focus on the arrival (not the departure) as you shift from 1st to 2nd, 1st to 3rd, 1st to 4th, etc., position.

Left Hand Independence

With a fixed first finger bar, play slurs and scales across all the strings with the rest of the fingers. Try all combinations possible.

Memory

To avoid embedding errors, do not start memorizing at the very beginning of learning a piece.

Fingerings

There are never definitive fingerings.

*What Brouwer most likely means to covey here is that fingerings evolve throughout the lifetime of learning a piece. Inevitably, we discover better, more efficient, more musical, more interesting ways to play passages and discard or change older fingerings as our familiarity with the piece increases.

Color

Exploit the three primary sonorous zones of the guitar: over the sound hole (resonant zone), over right part of the rosette (resonant and clarity zone), and near the bridge (clarity zone).

Harmonics

Do not pluck harmonics diagonally.

More Advice

• The position of the guitar to your body should remain consistent.
• Remember that the 2nd and 3rd strings tend to be the weakest so we must compensate when necessary.
• Pluck consonant chords with no arpeggiation. Pluck rare (dissonant) chords with arpeggiation for clarity.
• Velocity contains impulse and direction.
• Cadential ornaments should be in time.
• Resonance is at the heart of the guitar.
• Vibrato is used for intensity not rest.
• The thumb (left-hand) acts as a pivot during slurs.
• Forte is found at the limit of a beautiful sound.
• Breathe between phrases and project energy towards the end.
• During rasgueados the energy is channeled towards the 1st string.
• Anything that is repeated should be varied. Change either the color or the volume or the timbre.