Abstract: A method for the fragmentation and/or weakening of a piece of material by means of high-voltage discharges includes immersing the piece of material in a process fluid, guiding the material past a matrix formed by a number of high-voltage electrodes, which are supplied with high-voltage pulses. As such, high-voltage disruptive discharges occur through the piece of material whilst same is guided past the matrix. The high-voltage electrodes can be moved independently from one another along movement axes running substantially perpendicular to the passing direction of the work piece. And the electrodes are moved whilst the piece of material is guided past and whilst the high-voltage disruptive discharges are generated, in such a way that each follows the contour of the piece of material at a determined distance and are thereby immersed in the process fluid.