When playing a musical instrument, visually perceived musical symbols are translated into motor commands while simultaneously monitoring instrumental output, and receiving multi-sensory feedback. In addition, artistic and interpretational aspects have to be considered. First the mind has to have a clear idea of the music, tone, and movements of the playing apparatus (body) before starting to practise on the violin. It may be thought that repeated physical practice alone will result in achieving mastery as an instrumentalist, however what is essential is to be able to convey the mental perception of the movements to the hands. This article presents a cognitive approach to practising the violin; that is, practising by first seeing the musical symbols, identifying a musical structure, imagining the phrase, identifying the needed technique, taking notes, imagining the movements and the sensory feeling of the arms and hands especially, and the playing apparatus as a whole, together with the artistic and interpretational goals. Only when this mental process is completed, should actual practice start. This article demonstrates that mental practising is of utmost importance as it enables one to overcome difficulties, even in extreme situations such as the severing of the median nerve of the left hand. Four cases are presented to illustrate the applicability of this cognitive approach. Each case addresses violinists of differing technical and musical skill levels: a professional concert violinist and seven students at Hacettepe University, Ankara State Conservatory. The author, himself a professional concert violinist has developed, applied and observed this technique on himself for more than 8 years after he had an accident where the median nerve of his left hand was cut, and a nerve transplant was necessary. He was able not only to play the violin again, but to give public concerts during the early convalescence stage, without feeling in his hand, and a paralysed thumb muscle.