Even with a facility in the German language and a comprehensive library of the literature on genuine and fake cancels found on German stamps, one can often have difficulty determining what is genuine and what is not. At a minimum a reference collection built up over many years is essential in identification. Here are a few examples:
The stamp on the left (Scott #316 mint C.V. $0.20, used $6.50) has a fake cancel which is obvious when the stamp is turned over. The stamp on the right (Scott #293 mint C.V. $0.20, used $0.85) is “probably” genuinely used. Note there are 2 postmarks on the stamp.
This set of Scott #C15-C19 (mint C.V. $1, used $100.75) is virtually certain not to be good. Anytime there is a ratio of used catalogue value to mint catalogue value that is this high, a certificate is called for. In this set the 100 marks has a postmark, which might be genuine (if so C.V. is $9.75).
The next set Scott #C20-C26 (mint C.V. $1000 for NH, $177.95 for hinged, used $208) is a problem for the collector or dealer. It comes from a very strong collection and on balance we would give the postmarks a thumbs up, although we are not certain. Perhaps one or more of our readers can help with details. In any event we offer all 3 (essentially all the value is in the C20-C26 set) as a single weekly feature for $120. It can be purchased in our internet store at this link.