10 things to know before flying to Japan

1. Bring some cash. Keep in mind that the foreign Maestros are not working in Japan and the Mastercards are not working well to get cash but you should be able to take some at the Japan Post Bank and Citybank.
2. Do not forget to buy your JR pass. You can only buy your JR pass from outside Japan to travel around at a reasonable price on the JR lines. Do not forget that this pass is unfortunately not valid for all trains like the Nozomi one.
3. Carefully choose your hotels. Smoking is still allowed and most of the hotels propose internet connexion with cables so you won't be able to use your mobile phone depending on the hotel you have booked.
4. Book your WIFI device in advance. If you are an internet adict like me, you can rent a WIFI device at the airport allowing you to connect your mobile phone, tablet or computer for around 10 dollars per day. Working on 4G, you will access internet almost everywhere including trains. You will find plenty of operators providing this solutions at Narita Airport.
5. Do not forget to take an adaptor and keep in mind that no transformator is needed for devices from 100 to 240 Volts. If you forgot it, you will be able to find very cheep one (around 2 dollars) visiting any Big Camera store.
6. Buy your ticket for Ghibli Museum in advance. You need to buy your entrance ticket for the Ghibli Museum outside Japan. Visit their website for more information on how to get them.
7. Reserve your ticket for the sumo tournament in Tokyo. If you have the chance to come while a tournament is organized, book you ticket in advance to be sure to be able to attend.
8. Don't worry your mobile phone should be working if you got an European one.
9. Don't forget to bring your swimming suit. If you can try the onsen in Eve clothes. You can also try some hot springs amusement park such as the Yunessun at Hakone where you can take a bath in red wine!
10. I highly recommend you to bring good looking clothes. When I am in holidays I am tempted to wear only short and T-shirt with sandal, especially when it is warm. But if you wish to enter in some places, the men will need to have nice pants and when you will look at the very fashionable Japanese girls, you will be glad to get some nice dresses, high heels and make-up in your suitcase.