During this private concert, the documentary created by the Huygens-Fokker Foundation, directed by Sharis Coppens and Sander Germanus, about violinist/composer/music theorist Leo de Vries (1924–2018) will be shown for the first time. This will be followed by performances of several works by Leo de Vries on Fokker organ, flute, 31-tone guitar, and violin—an ode to a great musical-theoretical thinker.

Leo de Vries (1924–2018) studied violin at the Royal Conservatory in The Hague with Joachim Röntgen. Through theory lessons with Henk Badings and Martin Lürsen, he was introduced to the 31-tone system. From 1956 to 1960, he studied composition with Jan van Dijk, during which he also met Professor Fokker. He participated in a twelve-tone technique course by Wolfgang Hufschmidt, composed a piece in the dodecaphonic system, and then refrained from composing between 1968 and 1976 out of dissatisfaction with the system. Until 1985, he worked consecutively as a violinist with the Groningen Orchestra Association and the Rotterdam Philharmonic Orchestra.
From 1977 onwards, he developed quarter-tone music based on the meantone tuning technique. To perform this music, he had a special guitar built, and in 1980 a harpsichord. Between 1980 and 1988, he published several articles on microtonality. In 1984, he became an active member of the worldwide Music Modernisation Association. He was also part of the Rotterdam microtonal group. In 1983, Leo de Vries described in an article in Mens en Melodie three types of scales in quarter-tone music in which, when transposing to the next key, only one note needs to be changed. Since then, he discovered that this transposing principle can be applied to all tonal systems.
“The seven pieces from For 31-tone Organ were composed in the 6/31 scale: the 6 refers to the sixth tone (the supra-second). The scale used is eleven-tone and consists of a sequence of major seconds and sharps. In such a scale, certain intervals and chords can be emphasised at will. In piece 1, this is the sequence of seconds, particularly in the lower voice; in piece 2, the harmonic sevenths; in piece 4, the ninths in the broken chords; in piece 5, the major and minor seconds; in piece 6, the thirds in the lower voice; and in piece 7, the harmonic sevenths. In piece 3, I applied my rhythmic system DuTri: a rhythm consisting of notes with 2 and 3 pulses, very randomly distributed. I have dedicated this challenging music to our incomparable Fokker organ player Joop van Goozen.”