JR pass reservation for oversized luggage

hi all,

would like to seek some advice.
travelling to japan in a group during christmas/new year period.
I've purchased the JR pass via japanrailpass.net and have made seat reservations. read some articles that baggage area are reserved only for last row of seats in each car.

would there be any issues if i had booked a reserved seat but not the last row?
and does anyone know if I can cancel a seat reservation?

Thanks in advance!

would there be any issues if i had booked a reserved seat but not the last row?

Only if you had an oversized piece of luggage. Very few people travel with such large pieces of luggage!

and does anyone know if I can cancel a seat reservation?

Does the website not allow for cancellations?
If not, you can cancel them at ticket machines and ticket offices in Japan.

That depends on the amount of luggage. But I'm assuming that most luggage isn't big enough as to where the back row is needed. But as far as ticket cancellations go, yes, you should be able to do that last minute at the station, etc.

The rules are a bit different per Shinkansen line, but assuming you are taking the one between Tokyo and Osaka / Hiroshima you are only allowed to use the baggage area behind the last row if you reserved that last row.

Options
1) bring luggage that is smaller
2) rebook your seats
3) ship your large luggage from hotel to hotel by TaQBin

This baggage rule only for Tokaido, Sanyo, Kyushu and Nishi-Kyushu shinkansen trains.
https://global.jr-central.co.jp/en/info/oversized-baggage/
https://www.westjr.co.jp/global/en/howto/baggage/

Other Shinkansen lines and conventional line are not.
Hokkaido, Tohoku(Akita,Yamagata), Joetsu and Hokuriku shinkansen and.

But, there are also restrictions on the size and contents of luggage that can be carried on conventional trains.
https://www.jr-odekake.net/railroad/ticket/guide/other_tickets/baggage...
In fact, individual inspections like at airports are not conducted.

Only if you had an oversized piece of luggage. Very few people travel with such large pieces of luggage!

A 160 cm case or larger is not actually that big cf many of the cases on the market and in use.
"Very few" might be subjective, but for a typical shinkansen car (20 rows of five for 100 people) it is quite easy for there to be a dozen huge cases on a Nozomi service (the ones I have used most in the last few weeks - direct observation). During October (pre the tourist rush) booking the "last row" was tricky (even booking in advance) for Nozomi. For Hikari or Sakura services availability would be worse.
In particular, more tourists bring huge bags when visiting Japan (I see hundreds when doing my pick-ups at airports and on the trains) but even many Japanese travel with enormous suitcases.

thanks all.

had managed to cancel some of my reservations and booked the last row seats for some routes. almost all the trains are fully reserved during this period. reminder to self to avoid peak season. (Actually my second time visiting japan during the NY)