Saitensack is the development of new ways of playing (music?) for violin or viola. The instruments are neither specially prepared nor amplified. Essel developed the idea that playing the violin means: the violin plays. Ergo: the violin is played so that the violin plays. The strings are not held down, but subdued. Through a special bow technique natural oscillations are stimulated. Only through direction of the bow is the sound formation influenced, which is otherwise left to chance, or to the violin.