South Korean 10 won with blank reverse

[mactim]

I have a coin that is identical to a South Korean 10 KM# 6a on the obverse but the reverse is completely blank. It in the same diameter and thickness. Can anyone tell me what this is? Is it an error? a pattern?

Thanks in advance for any help.

[Figleaf]

Not without a picture, weight and diameter. This can be an error or a homemade novelty.

Peter

[mactim]

Thanks for the response. I am attaching pics of both sides. The diameter is 22.86 mm exactly like the actual coins. I don't have a scale yet so I can't confirm the weight.

[Figleaf]

Scales are not expensive and very helpful.

I suspect this is homemade. You can make sure with the weight.

Peter

[mactim]

I have ordered a scale but it hasn't arrived yet.

How could some one make that at home? Would someone grind one side down? It appears to be struck just like the normal coin on the one side and perfectly smooth on the other side. There are scratches and wear from circulation but nothing that looks like tool marks.

I just curious what to call this.

[Figleaf]

The Poongsan factory that makes the blanks for a number of countries, including Korea, delivers them with an upended edge on both sides (see pic from their web site.) However, this is a somewhat older coin and their practices may have been different in the past.

Anyway, since the reverse does not have an upended edge, it is suspect. The effect can be achieved by any kind of grinding machine that grinds sufficiently fine. One of my acquaintances, who works with lens-making machines says those machines could do it and make the surface as smooth as satin. Less sophisticated machines can do it too, but the rougher the grind, the more traces you will find.

Peter

[mactim]

So why would someone do that? To fake an error? Or for some decorative purpose?

[Figleaf]

Yes to both. Another possibility is to demonstrate a machine, but faking an error is most likely. It is done relatively often. However, wait for those scales before jumping to a conclusion.

Peter

[mactim]

Ok, thanks. I'm kink of new to all this. I've been collecting or rather accumulating coins since I was a kid but have only now getting serious about it

[Prosit]

Why would someone do it?

I have done that and did it just to see if I could and what it would look like.

Other reasons.

to prepare that side for an engraving just for the sake of art or for a love token
To prepare that side to punch something into it to make a token to sell (I have tokens like that)
to fake a token for a vending machine
to fake another coin's weight to use in a vending machine
Someone was bored

I think to make a fake to sell to a collector least likely as most collectors would be very leery of this item knowing how easy they are to make.
I also can't think of a way the error could happen legitimately so faking one makes little sense to me.

And many other reasons too I am sure

Dale

[mactim]

The scale i ordered finally arrived. The coin with the blank reverse weighs 3.83 g while a normal coin weighs 4.06 g. So it does appear that someone ground the back off.

[Figleaf]

Congratulations with the new scales.

Peter

[Verify-12]

Most certainly ground down mechanically.

You can even see the "0" in the "10" faintly visible.

I've seen someone sell a 10 Won coin at bay with all the legends ground off except for the denomination numeral.

And I agree with the upended edges:  They are made by a device called an "upsetting mill".  The 10 Won coin of the design 1966-1982 on this coin had upended edges.

Thanks for sharing!