Currency
The official currency is the Yen (円, en) – latinized symbol ¥, ISO 4217 codes: JPY and 392 – no other currency is normally accepted. Yen comes in bills of  10,000, 5,000, 2,000 (rare), and 1,000, and in coins of 500, 100, 50 (with a hole in the center), 10, 5 (in copper with a hole in the center), and 1 (in aluminum). In general, all major international credit cards are accepted, but shopkeepers often prefer cash. Rechargeable prepaid cards (Suica, Passmo, etc.) are accepted in many establishments and not only on national means of transport. To know more: Yen (from Wikipedia).

Social behavior

• In Japan cars drive on the left side of the road, therefore, when crossing the road, it is advisable to always look to the right first to see if any vehicles are coming. Traffic lights are always respected even by pedestrians.
• Smoking is prohibited in most cities and there are designated smoking corners located in various locations.
• On public transport, it is good manners not to speak loudly or make telephone calls.
• When getting on public transport, you queue and stand to the side so that passengers can get off before getting on.
• It is not recommended to eat while walking or on public transport, as it is considered rude behavior; long-distance trains are an exception.
• Avoid blowing your nose loudly.
• Pointing the finger or staring at a person is considered unpleasant behavior.
• When paying, avoid giving the money directly in hand but place it in the always present tray; counting change after taking it is offensive.
• When eating with chopsticks, never stick them in the food.
• Never throw paper or anything else on the street even though paper bins are practically nonexistent; the waste is to be taken home.
• In many places, including public ones (traditional restaurants or some temples), it is necessary to remove your shoes.
• Tattoos: in Japan tattoos were the exclusive legacy of the criminal elements and are still frowned upon today: almost all thermal springs, swimming pools, or public baths refuse entry to tattooed people unless they can hide it in some way.
• In public baths/spas you must wash yourself completely before entering the tub and do not wear bathing suits.
• It is not customary to tip.
• The Japanese do not shake hands but bow: to say thank you, simply nod your head hinting at a bow.
• Both Shintō and Buddhist temples are places of worship therefore it is advisable to dress and behave accordingly.

Plugs and electric energy
the alternating current voltage of the electricity grid in Japan is 100 V, with flat parallel pins type sockets and plugs (type A); the frequency in the north-east of the country (Tokyo) is 50 Hz, while in Kansai (south-west) it is 60 Hz, a difference which does not have much influence in almost all cases (except for electric clocks and similar). Plug converters are on sale almost everywhere. Modern electronic devices (computers, cameras, phones, tablets) normally work without problems, as long as the input voltage is indicated on the power supply transformer as "100-240 V ~ 50/60 Hz", which means it works with an electric tension between 100 and 240 V and a frequency between 50 and 60 Hz. To learn more: Electrical plug (from Wikipedia).