How much JPY can I buy bitcoin?

Can you please elaborate on the process of converting Japanese yen (JPY) to Bitcoin? What factors affect the exchange rate, and are there any fees or other costs associated with the transaction? How do I ensure that I'm getting the best rate for my money when purchasing Bitcoin with JPY? Is there a minimum or maximum amount that I can buy, and are there any restrictions or limitations that I should be aware of? Additionally, how do I store and secure my Bitcoin once I've purchased it?