When you come to Japan, you may take a train such as JR East or Subway. I advise you to buy a Suica card at the ticket-vending machine of JR station.
This is a type of the deposit IC card for train system such as JR or Subway. So you can go through the ticket gate with this card.
Also when you return this card at the JR East station when you leave Japan, the service charge of returning is yen 210 so you can get the cash of balance.
You don't need to buy the train ticket in each case when you take a train. It's a pain to check the coin and line up each time when you buy a train ticket. So this card is very useful.
Also you can charge the value into this card at the station. The upper limit is yen 20,000.
Suica is the trademark of JR East so if you go to Osaka area, then you can see the another name of IC card like ICOCA or PiTaPa. PASMO is compatible with the Suica Card in Tokyo area too.
Each train companies has each card name and design but the basic system is almost same.
Pls see more information at JR East Travel Information or PASMO site.
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