A method for a die casting with a casting device which includes a casting valve with a valve piston and a post-compression piston configured to provide a post-compression. The method includes providing a casting valve in a closed position and a mold cavity which is cleaned and prepared for a mold filling process, opening the casting valve for a casting, filling the casting valve with a melt, closing the casting valve after the filling with the melt, cooling the casting valve and the melt, and removing a cast part. A post-compression is provided to the melt during the cooling by the post-compression piston.