This has to be the best and cheapest way to travel around Japan, providing you go everywhere. It has to be purchased outside of Japan and then the invoice is exchanged for a pass at one of the stations (maybe the airport I can't quite remember). You cannot buy it within Japan as it is only for tourists.
The pass works on all national and local trains using the JR lines.
Don't forget to flash the pass as you walk pass the station guards.
I recommend you download the timetables too.
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