When going to Japan, ofcourse you’re going to need yens.
As stated before, you’ll need cash, and not all bankcards will work there.
So you have 2 options; get the yens in your country or take cash with you and change it in Japan.
Now what I noticed is getting the yens in your own bank is the best option.
Be sure to check with your bank how long upfront you need to order them. Mostly it will take a week, but most banks have only one day a week of delivery.
For example; my bank has foreign currencies delivered on thursday. All orders need to be done before Thuesday evening of that same week. Meaning I had to order 1,5 week to 2 weeks before my departure.
On having a good exchange rate, you’re better off at your bank too.
A hint; order and change at the counter an as large amount as possible at once, don’t fragment it in seperate changes or orders, make the seperation (for different people or purposes ex.) afterwards. The larger the amount the better your exchange rate will be!
When you can’t get all the money at your dispossal early enough to get it changed into yen at home, then the best idea is the get cash into Japan and change it at the airport OR if you’re certain your bankcard will work there change it from your card. Go to Narita’s website here to see the daily exchange rate for cash & card and possible accepted cards. The rate is better for cards, but its a risk ofcourse.