It appears to be an error caused by a filled die. That is, where grease or dirt or other such material has literally filled the incused `1' in the die so that when the coin is struck there is no space left for the metal to flow into the `1', resulting in a blank. Normally you would see at least part of the number / letter/ or device that has been filled, even if only a ghosting effect where it should be. On that coin, it looks to be pretty much non existent. Unusually so. Ian
I'll bet there is more to the story than that. That blank "1" space is as clean as a whistle. There is something goofy about that "coin". Countries around the world produced a lot of unusual (and non-recurring) money and script after WWII.
Lol! You can read that statement of yours different ways. We've all been looking at it and can clearly see that the one is missing (and the space where a `1' should be). If you mean that when you look up close that there's a ghostly outline of a 1 (or even part of) then it's more than likely that it is evidence of a filled die. If not....then the mystery of the missing `1' is probably down to something else (and unknown to me). Sherlock Holmes might be able to find out ....or someone with a better knowledge of error coins. Ian
Perhaps the die was put into the coining machine through an oversight,as the dates are usually completed in the working die.It is a very interesting & unusual error coin. Aidan.
Seems to be how these were designed. Can't quite tell from THIS "high resolution" ebay image. HERE's another....1943, 1944, 1945....the 1945 appears to missing the 1
Quite possibly it was intentional to mark coins minted under occupied Belgium during WWII. Just a guess.