JR Pass Reservation

My family and I already have our vouchers for our 7-day Green JR Pass - we bought our tickets through KLOOK before our trip which is next month. From Tokyo station, we will ride the Tokaido shinkansen to get to Osaka. Will we need to reserve our seats prior to our shinkansen ride or does our pass already ensure a reservation of seats? Thanks

If you want a reserved seat, you need to make a reservation, which is free with a JR Pass. Once in Japan, go to a JR ticket office with the details of the train you want to reserve and your pass, and the staff can make your reservation.

To fully make use of your GREEN pass, meaming riding the green car, you MUST make reservations. The JR pass allows you to use the Hikari and Kodama services without making a reservation, but only on the non-reserved cars. You need to make a reservation prior to boarding a Green Car on either service.

"Will we need to reserve our seats prior to our shinkansen ride" - As mentioned in the previous comment, reservations are MANDATORY if you'd like to ride the first-class Green Car on a shinkansen service, which is of course the whole point of investing in a more expensive Green JR Pass. Whether trains are empty or crowded is beside the point; you are required to obtain assigned seat tickets before travelling in the Green Car. Of course, if (for whatever reason) you need to take a particular shinkansen train at short notice, without time to make a reservation, you'll be able to hop straight aboard and take a seat (if there are any) in one of the economy-style non-reserved cars with just the Pass.

"[D]oes our pass already ensure a reservation of seats" - Unfortunately not: if trains are booked out, then they're booked out. I always invest in the Green version when travelling with a nationwide JR Pass, and Green Cars do sometimes get filled up at peak seasons/times on certain segments; in those cases I've no choice but to get a reserved seat in an Ordinary Car instead.

Cheers.

If your only trip is Tokyo to Osaka then the JR pass is an expensive way of doing that trip. Even for a round trip the savings are marginal.