Help identifying a Chinese (Empire) coin?

Not sure what I have here. It's 29mm and 3.8 grams. Uniface. (It's bright brassy -- which gets lost in my poor images.) Thank you.

It's a Vietnamese cash coin. As same as https://en.numista.com/catalogue/pieces33936.html

Цитата: "be.hanoi"​It's a Vietnamese cash coin. As same as https://en.numista.com/catalogue/pieces33936.html
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​agree that drdrew's coin looks like numista's 1 van of vietnam; however, how do we reconcile that his coin is much bigger (29mm) than the 1 van (23.2 mm) listed in numista?

There is another 1 van at https://en.numista.com/catalogue/pieces46521.html which is 25 mm but that is still 4 mm smaller than the coin in question.

are we looking at a charm or fantasy or feng shui special?

Thank you for the helpful information. It turns out that when I just grabbed a ruler to measure this coin I read the ruler wrong; it's 24mm, not 29. (Digital calipers are clearly better for me!) Drew