Korean ID please

OK, I've had a Korean coins for a long time which I haven't been able to ID. The main reason for this is the grade. It's an about poor, hehe! I've been trying to photograph it as good as I can with my mobile phone. I can barely see the characters myself, but I hope that someone here could help me out.

I might have some ideas about some of the characters, but I don't want to misslead anyone to start with, so I won't say anything at first.

The coin weighs 4.3 gr, and the diameter is ~23.74mm

Anyone, here it is:



I tried to take clear photos, but it was extremely difficult, so I distorted the colours in the picture in an atempt to make the characters clearer.

Here's the top character:


Here's the right character:


The bottom character:


And the left character:
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Quote: "ngdawa"​​The coin weighs 4.3 gr, and the diameter is ~23.74mm
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​Anyone, here it is:
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​3 of 4 characters readable.....?? 國通寶
perhaps this Chinese coin..... 唐國通寶?



https://en.numista.com/catalogue/pieces42105.html

Quote: "bbybugs"​​​3 of 4 characters readable.....?? 國通寶
​perhaps this Chinese coin..... 唐國通寶?
​
​
​
​https://en.numista.com/catalogue/pieces42105.html
​

​I've been consider the characters 國通寶 as well. But I'm more in for the 東國通寶 or 東國重寶 constellation. I am far from sure though.

Please take a look here and let me know what you think.

can't read coin clearly, i just guess
probably you are right, korean 東國 (tong guk)

I'm not sure, it was just an idea.