Abstract: The specification describes a two-dimensional symbol code for representing binary data, which symbol code is constructed from a plurality of graphical symbols arranged next to one another, wherein the symbol code is formed from precisely two different symbols having the same surface area which differ in their areal brightness distribution and each code a value from a binary data word. The symbols have a complementary brightness distribution. In a method for reading this two-dimensional system code, the system code has a filter applied to it which matches the brightness distribution of one of the two complementary symbols, wherein in the event of a match one symbol is recognized and in the event of no match the other symbol is recognized.