Koson Coin

Hi everyone,

I have this ancient-looking coin with the inscription Koson ,wheighting around 10 grams .I believe it's bronze.

Could you help me identify : 

- if it looks authentic or a modern replica

- the approximate period

- its potential value of it genuine.

Thanks in advance!

It's a real replica although I'm not sure of what.

N#388806

Edit: replica of this: N#188617 I think.