Tokyo to shirakawa-go

Hello there !

I would like to ask if my itinerary are better using jr pass (tokyo only) or not.

From narita i'll go to shinjuku area and travelling around tokyo. And day 4, i'll go to shirakawa-go from shinjuku, Then back to shinjuku in one day. Day 5, i'll go to sapporo via flight and stay at sapporo in 4 days. Is it necessary to buy jr pass tokyo only and whether jr pass tokyo cover to shirakawago? Or should i buy jr pass nation wide ?

If anyone know please inform me, because it's my first time travelling alone with my fiance.

Thank you so much ! ❤️