The penalty for counterfeiting and forgery of banknotes (imprisonment at least two yrs) appeared to the upper right corner with the reverse of all third sequence banknotes. Note This is actually the put up-1970 variant, featuring "Freiheitsstrafe" as an alternative to "Zuchthaus". Regular security measures at the time were guilloches, https://buy-bank-notes-in-germany77765.bloggerbags.com/32879717/bank-note-and-currency-note-fundamentals-explained