Traveling Japan can be difficult because of Language barrier.
Different culture, different language, different people.
It is FUN but sometimes it really need some help by internet.
If you would like to be connected, the prepaid SIM will be very useful.
Prepaid SIM card can be booked online or it is also available at most of International airport in Japan.
If you would like to book a Sim card for sure, try Prepaid SIM cardbooking from here.
You can pick up at Tokyo station or If you arrive at Nagoya, it is also available to pick up at Chubu international airport.
Enjoy your stay in Japan with your Phone connected!