One Side Blank

that can't happen on a U.S. coin.

That is an interesting topic. I say that since I've heard so many times that it is not possible but have seen many one sided coins at coin shows for sale as error coins. And some have been slabbed but of course that may well be one of those many fly by night TPGS places. I wonder if anyone REALLY, knows.

A coin struck from only one die cannot, logically exist.

I hate to go all zen on you, but imagine the sound of one hand clapping. Logically, you can't, because a clap is defined as the result of two hands hitting together.

Likewise, a coin is the result of two dies hitting together with a blank piece of metal in between them. Theoretically, something that resembles a one-sided coin could be struck by a mint, but it would have to be made by inserting a specially prepared "blank" die on the other side.

So, where do all these "one-sided coins" come from? Several possibilities come to mind.

A machine job - someone ground or filed off the other side. This might be done for all sorts of reasons... perhaps someone was making a "love token" and never got around to doing the engraving. Perhaps it was being turned into a two-headed coin or other "trick coin". a similar effect can also be created "accidentally" by a coin getting stuck in a machine of some kind. Such a coin will weigh slightly less than a "normal" coin of the same type.

Split planchet - small bubbles of gas sometimes get trapped inside the piece of metal the coin blanks are made from. This creates a weak spot there, and the finished coin, after it is struck, can split apart at the weak spot. While such an occurrence can be a legitimate mint error, it's all to easy to create your own "artificial" split planchet simply by taking an intact coin with an (invisible) bubble inside it and hitting it hard on the edge (by, say, dropping it from a height). Such a coin will weigh significantly less than a "normal" coin, and the back side will look rough and uneven, like raw unfinished metal, rather than be completely smooth and flat.

Uniface pattern or die trial - this is pretty much what I was describing earlier, where a specially made blank die is inserted into the press and a coin struck with just one working die. This is usually done to test a brand new design before coinage production actually begins. Such items are considered "experimental", like pattern coins, and therefore extremely unusual; they almost never leave the mint. The "blank" die is often not completely blank; Australian examples have the word "model" in the centre. Some mints make them out of a different metal (such as lead) to keep them distinctive from subsequent normal coinage. Such a coin might weigh exactly the same as a normal coin, or it might weigh much less - or much more, depending on whether the metal used was the same.

Electrotype or cast copy - "museum replicas" of rare and valuable coins are often made only one-sided, since only one side is needed to be shown in a display case; sometimes museums even sell such copies to the public, or make them available to interested parties on request (I believe the British Museum used to do this). The "blank side" of such a copy will often look raw or unfinished, and may have details of the copy (such as a collection reference number) stamped into it.

Sap, so apparently it is impossible for two planchets to be stacked on top of each other between the dies. But what exactly makes it impossible?

You can find them listed under "trial strikes" at the back of the Krause listings for each country. My copy of Krause lists under "Great Britain" a series dated 1926 with the other side blank except for the word "MODEL", and a second series dated 1963 which are truly blank on the other side, or uniface. Under Australia, there are some Australian uniface trial strikes shown; some uniface obverses from the 1920's and some uniface reverses from 1937.

If the coin design was never ultimately adopted for use, you might also find uniface die trials listed amongst the "patterns". All known genuine 1909 Australian florin patterns are uniface.


What censoring? If there was any, it got moderated away before I refreshed the page. If you mean where it says "blank", that's what I meant, "blank", as in empty, clean, devoid of any detail.

Hi steve got a bag of donuts LOL