How to make this error on Vietnam 2 Xu 1975?

Dear Numista members,

I happened to purchase this coin at a fair. You can see that in the middle of the coin, there is a recessed circular area, creating a raised rim compared to the surrounding surface. This circle is very well-defined, and it seems like the die surface was cut down. I don’t understand why this error occurred—can anyone help explain it?

Thank you alot!

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Cool find.

Appears to be what is referred to as a “Ring of Death”.

It is caused by a coin rolling machine.

It is considered to be post mint damage.

DSC07625

Cool find.

Appears to be what is referred to as a “Ring of Death”.

It is caused by a coin rolling machine.

It is considered to be post mint damage.

Thank you for your feedback.

As I understand it, the Ring of Death refers to damage caused by the Coin Rolling Machine after the coin has already been struck. This would result in significant damage to the details. However, please take a close look at the details on this coin. They are still well-preserved. The ring appears to be beneath the details, so in my opinion, it can only be damage caused by the die during the striking process.

 Yes if it was the ring of death the scratch would be on top of the lettering.  To me looks like the die is on its last legs.

This is NOT caused by a coin packing machine, since the letters would have been cut as well. It is probably an error in the blanc?

 To me looks like a collar break.

edit First thought dis crack but it not like a die crack. To wide.

Thanks guys for enlightening me!

I didn't consider a die crack or collar break. 

I've never seen one that was that round.

I don't think it's a blanc error. Because if the planchet were defective, the striking force from the die would flatten the affected areas in the field during the striking process. Therefore, I still believe that some kind of error occurred on the die.