Please, help identify this old Chinese or Japanese coin!

Dear friends,
I will appreciate if you could consult me on this coin:

Is it real or fake? China or Japan?

Thank you very much!

I think it´s this coin:
https://en.numista.com/catalogue/pieces20604.html

Citation: "alamir"​I think it´s this coin:
​https://en.numista.com/catalogue/pieces20604.html

​Dear Alamir,
Thank you very much indeed! Do you think it is a fake or can it be real?

this is from the Tang dynasty, emperor Kao-Tsu (618-626 CE), a so called "Kai-yüan" coin (it reads Kai-Yüan T´ong-bao), with a "nail-mark" on rev., ref. no. Schjöth 315; whether it is genuine or not is not easy to find out, I guess it depends on where you have it from ;-P, - anyway these are not scarce (genuine or not).

Citation: "8ERGmann"​this is from the Tang dynasty, emperor Kao-Tsu (618-626 CE), a so called "Kai-yüan" coin (it reads Kai-Yüan T´ong-bao), with a "nail-mark" on rev., ref. no. Schjöth 315; whether it is genuine or not is not easy to find out, I guess it depends on where you have it from ;-P, - anyway these are not scarce (genuine or not).

​Thank you very much for the information! Actually, this coin came from a collection in Switzerland. It just looks very good... I think genuine ones are likely to look a lot worse considering the age... :)