The String Sextet, Op. 65, comes from much later in Braga Santos’ life: the manuscript is dated 16 March 1986. The impetus for its composition was a concert Braga Santos attended at the Gulbenkian Foundation, at which the Camerata Lysy performed Schoenberg’s Verklärte Nacht (also a sextet); indeed, Braga Santos’ Sextet is dedicated to Alberto Lysy, the Argentinian, Swiss-based violinist and conductor who [LATER?] taught his daughter Leonor. Verklärte Nacht is often performed by string orchestra and that, indeed, was how this Sextet was first heard, with the Gulbenkian Orchestra conducted by Grzegorz Nowak, on 10 June 1986, in Portimão, as part of the
X International Algarve Music Festival. The premiere of the original version was posthumous, on 10 July 1989, at the Teatro Nacional de São Carlos. 11
The Sextet uses a language quite different from that of the two Quartets, as might be expected, given its chronological place in Braga Santos’ output. But it is not so much a question of replacing and adopting a new technique over another, rather an expansion of the available resources, which include accentuated chromaticism, atonal melody, alternative ways of dividing the eight-note [OCTATONIC?]scale, intervallic thinking in harmonic cells based on the fourth, and extremely varied and detailed modes of execution (attack, articulation, phrasing). It is therefore an amplification of Braga Santos’ means of expression, a synthesis in which the old is not completely vanquished: his stylistic fingerprints still appear frequently, but now as if diluted amid more recent stylistic acquisitions.
The opening Molto largo  is in ABA–coda form, with A marked by broken
melodies (first violin, cello) and B by harmonically static landscapes, stripped and desolate, in which melodic gestures appear lost, and with fleeting evocations of the melody [SINGULAR OR PLURAL?] of the A section.
The second-movement Allegro ben marcato , which comes attacca subito, is almost an exercise in the gradual acceleration of time. Formally, there is an exposition, with two themes, and a recapitulation, but the development is replaced by a tense kaleidoscope of varying rhythmic ostinato – a pretext for a kind of study of different modes of execution, in a charged texture punctuated by broken, urgent melodies. The coda condenses the rhythmic events without easing the tension.
The Andante which opens the third movement  revisits the atmosphere of the first, being concluded by seven bars of harmonics. Then comes an Allegro, which operates a process similar to the middle section of the second movement, but here there are two catalysts: melodic transformation and metric oscillation. An abbreviated return of the initial section connects directly to the coda, where a torrent of semiquavers ends in an airy final chord of overlapping fifths.