No other composer influenced Fernando Sor more than Wolfgang Amadeus Mozart. Sor's Introduction and Variations, op. 9 are based on the aria 'Das klinget so herrlich' from the opera 'The Magic Flute'. In his theoretical guitar treatise 'Méthode pour la guitare' Fernando Sor explicitly describes the tonal possibilities of the instrument and compares its tonal colours with those of orchestral instruments. In his Opus 9 he skillfully implements this concept in the well-crafted an felicitous introduction, which then develops into an orchestral overture.
(…) These Mozart variations were, at one time, one of the most popular pieces to perform and record, often without the Andante Largo introduction, which is presented in this edition. For those who don't know, this piece has the introduction, a theme and five variations all based upon the aria "Das Klinget so Herrlich" from Mozart's opera The Magic Flute. Very tuneful throughout and featuring some very beautiful and well-crafted variations which showcases the performer's technical skill, this work is probably due for a resurgence amongst the multitude of younger players. Nothing too new here in this edition although the right hand fingering is quite nice to have and the presentation is excellent. Classical Guitar Margazine 11/2012