If you travel to Japan, these tips can help to make your journey smoother.
Carry some cash
Cash is still very widely used in modern Japan. Some vendors don’t accept credit cards. Even if cards are acepted, many small vendors don’t take American Express
Many parks and gardens only sell tickets for cash. Those are usually 500 JPY for adults.
Suica card
Get the Suica card or use the Suica app on your phone. You need 500 JPY cash to buy the Suica tap card at train and subway stations. This allows you to ride the subway and city buses, assign your Shinkansen express train ticket to it, pay for luggage storage lockers, buy some park tickets, and food at the railway stations from vending machines and from food vendors. It looks like the Japanese government wants to avoid credit card transaction fees, so they developed their own payment system.
To get the Suica card
At airports you can get the red Suica Welcome card for free, in the city you can only get the green one for 500 JPY.
At railway stations find the machine with the black sign for Tickets and Commuter Pass

Select the “Blank card” option on the screen, and pay 500 JPY cash to get the plastic card. You cannot use the card fee for travel or purchases. The machines accept larger bills and return the difference in cash, no credit card is accepted. In a separate transaction charge the card with cash only. A typical subway ride is around 250 JPY, so plan accordingly.
The card fee is refunded when you return the card at the end of your trip.