JR Pass is the famous Japan Rail Pass that can only be purchased abroad and used by foreign tourists and Japanese nationals living in a foreign country.
I struggled a lot whether to purchase a JR pass or not driving myself crazy and my wife as well in the process. I made a spreadsheet* having all possible combinations and in the end I decided to go for the ‘E-Voucher for Kyoto Bullet Train Open Ticket Package & Kyoto Sightseeing One-day Pass’.
Kyoto was the only city in Japan beside Tokyo that I wanted to visit and I would have had time for during my 7 day trip to Japan. And this voucher was the best choice in the end, as I could take any train (JR Pass limits you) so when I left Kyoto back to Tokyo I did not even bother to look at the schedule, I think it was a high speed train evey 10-20 min.
*I read in a book that people spend more time deciding what microwave to buy than analyzing their investments. This is true for me too. I spent thousands of $ on shares without thinking too much (and of course I lost) but for saving a few $ I spent lots of time.