This coins are a replica based from the ones you get in the collectors edition with the same size.
Now some info about the text on the coins: 葦名通寶 is the text.The first part 葦名 is Ashina which is a name used in the game.通寶 is an inscription used in currency (Tsūhō in Japanese, or Tongbao in Chinese).
They are made to imitate ancient coins like the ones found here: https://en.wikipedia.org/wiki/Japanese_mon_(currency)
Thanks for purchasing and happy printing!