Just FYI – Bank of Japan is the name of the central bank in Japan, where Japanese money are printed. Big difference from United States. They don’t deal with people because that’s NOT their job.
Usually you will use regular banks when you visit Japan to exchange currency or to withdraw the money your family sent to you on regular basis.
Here are some tips for you:
1) They close at 3:00 p.m. on weekdays and noon on Saturdays. Sunday they are closed.
2) After hours, you have to pay a fee when you withdraw your own money. Whether you use your own bank’s ATM or not. They will automatically take 300 yen or so from your own money in your bank account. Since cash is still preferred in payments in Japan, you have to keep some cash in your wallet especially on weekends, when you might have to pay a lot for fun! Then, you run to ATM to withdraw cash with your ATM card. You end up paying 300 yen (plus tax) or more to the bank. You plan well and withdraw your money on weekdays and during their business hours.
3) Try to use local banks, instead of big names. They are usually more friendly and offer you great customer service.
(You don’t want to deal with guards, do you?)