7. Is there any limitation on the usage of the number of coins? How many coins can you use in daily transaction?
According to the Japanese Currency Law, maximum pieces of up to 20 coins of the same denomination can be used as legal tender. Rejection of the acceptance under 20 pieces of the same denomination is prohibited. In case of over 20 pieces you can reject accepting the coins in daily transactions.
Coins are useful in small transactions. Transaction-wise it is inconvenient for you to accept and to store large amounts of small coins.