>> As of this posting the exchange rate at (USA) Bank of America is ¥141 to $1. No fees.
I had a BA account like that. It is good for some walking around money.

Better MIGHT be to use an ATM depending on fees imposed by your bank or credit union. It could be five bucks plus 3% exchange fee! A credit union card can likely beat that. Not all Japanese ATMs accept cards from foreign banks. Totally expect to find one at KIX but am not sure about ITM. I think it is Citi Bank that has ATMs at international airports. The Japanese banks charge a buck or less.

Best is to use an ATM/debit card that rebates the bank fees, e.g. one associated with a brokerage/401K account.

There is a 1% charge by Visa for processing but, after whatever ATM fees you are charged, they process the exchange at the interbank rate

Japanese ATMs (7 Bank, at least) have, unfortunately, started offering a "dynamic currency conversion" DCC option. This is where they give the options to 1) charge your bank the amount of yen you chose or 2) charge your bank an amount in dollars. The second option, showing you the USD amount, is just a kick in the nuts. I advise not to do it.

Make sure your credit cards have "no foreign transaction fees".