Under the Foreign Exchange and Foreign Trade Act, any single transaction which involves a payment or receipt thereof that exceeds an amount equivalent to 30,000,000 JPY and has been carried out between Japan and a foreign country, or between a resident and a non-resident, must be reported to the Ministry of Finance.
Said payment or receipt thereof also includes all transactions involving the use of fiat currency, such as JPY and USD, in addition to any transactions involving the use of crypto assets (cryptocurrency).
For further details, please refer to the Ministry of Finance website.