«Language as Chiffre» is an investigation of Wittgenstein’s theory of symbols, emphasizing the delimitation of conventional signs into a language of gestures, pictures and any other expressions, just recognizable as significant. The theory is explained and shown as practised in Wittgenstein’s typescripts and manuscripts, which communicate not just philosophy, but technical details about German military projects, and even alludes to escapes from Germany, all hidden in a masquerade of ‘nordisms’ and ‘germanisms’. The historical background of Wittgenstein’s anti-fascistic spy-actions is discussed as an example for his concept of language, as acting with and through signs limited by rational induction. The systematic approach of the book develops this idea through different grades of formalization in language. Logical forms, adequacy of formal representations and the modal concept of bipolarity are discussed as motive for the high value of the symbolism, that can function as extension, axiomatic structure or as transparent syntax of signs. As based on unconscious essentials of thought, indicated by transgressions of rationality, transparency of a symbolism does only mean that everything not reducable to physical reactions can be apprehended as a sign. Alternatives of formal systems show, that formal languages or calculi are in this sense not merely syntactical structures, but language. Examples are given.