Tokyo is known as the city with the highest number of the Michelin starred restaurants in the world, but that is not the end of the story. There are more than 150,000 reasonably priced restarurants in the city. Streets lined with skyscrapers and small bars coexist with shrines and beautiful gardens. It is definitely a must-visit city.
https://www.going.com/guides/tokyo-most-michelin-stars-in-the-world
Though use of credit cards and e-currency has increased in recent years, Japan is still largely a cash-based society. Here we send some useful information for your visit to Japan.
The national currency of Japan is the Japanese Yen (¥). Most of large stores, restaurants, and taxi accept major credit cards, VISA, Master, UnionPay, and some debit cards. However, some small stores and lunch places still only accept cash. It is best to exchange cash before leaving your country. Otherwise, you can withdraw cash with your bank card or credit card at an ATM at the airport upon arrival. ATMs are located as soon as you exit the arrival gate at the airports. Considering that cards and electronic money are accepted, 20,000 yen in cash would be sufficient for a week. See also this link.
https://www.worldnomads.com/explore/eastern-asia/japan/money-in-japan
Suica is rechargeable IC card and can be used on trains, subways, monorail, buses, and taxi in Japan. You can also pay with Suica at any store and restaurant displaying the Suica logo.
You can purchase Welcome Suica from the JR EAST Travel Service Center at Narita Airport, Haneda Airport and major stations or from the Welcome Suica Ticket Vending Machines at Narita and Airports. See the web page below for details on Welcome Suica providers and opening hours.
https://www.jreast.co.jp/multi/en/welcomesuica/welcomesuica.html
Suica card & Welcome Suica card
mobile Suica is mobile e-money on iPhone (same function with SUICA card.) If you are using iPhone or Apple watch, you can now set up your iPhone or Apple Watch using the following instructions.
https://www.japanlivingguide.net/living-in-japan/transportation/mobile-suica/
You can use your iPhone of Apple watch just by touching it at the gate. Mobile Suica is rechargeable from major credit cards, Debit cards and Union Pay. If you are using Android bought outside of Japan, sorry so far it is impossible to install Suica in your phone. Please buy a Welcome Suica card by the vending machine at Narita or Haneda Airports or major JR EAST stations.
Utagawa Hiroshige, Suidobashi Surugadai in "One Hundred Famous Views of Edo" (1857)
(Tokyo Fuji Art Museum)
Koishikawa Kourakuen (photo by Gribeco, (CC BY-SA 4.0))
Akihabara (photo by IQRemix and W.carter, (CC BY-SA 2.0))