Validity of the JRP on the last day

Hi!
Does anybody know whether the validity of the 7-day JRP expires *strictly* on midnight of the 7th day, or there are more conditions to it?
For example, can I board a shinkansen at 23:05 on the 7th day from Tokyo, which arrives to Utsunomiya at 01:03 AM, i.e. on the 8th day?
If yes, what about the case I have to change trains after midnight without exiting the turnstile area? Let's say I board a (normal, kaisoku or whatever) train at 23:00, and I have to transfer at 00:20 AM to another JR train. Would that be OK as long as I start the trip on the 7th day and don't leave the turnstile area?
Thank you!
Denis

For example, can I board a shinkansen at 23:05 on the 7th day from Tokyo, which arrives to Utsunomiya at 01:03 AM, i.e. on the 8th day?

Such a shinkansen does not exist! All shinkansen trains stop operating before midnight.

The rule for validity expiry is as follows:
If you happen to be on board of a train at midnight, the Japan Rail Pass remains valid until the end of your journey, i.e. until you leave your final station through the ticket gates. This is true even if you transfer trains after midnight. However, if you transfer to a shinkansen, limited express or express train after midnight, the pass will not cover the express supplement for that train anymore.

From: http://www.japan-guide.com/e/e2361.html

In a case where you are traveling with your Japan Rail Pass when the last calendar day of its validity ends,
you can take another JR rapid or Local train (because that JRP is still valid on JR basic fares) until you go through an exit gate at a station,
but you cannot take another JR Shinkansen, Limited Express or Express train only with that JRP (because it is not valid on any JR surcharge after the last midnight).

If the operation of Shinkansen happens to be delayed much and you are traveling with your Japan Rail Pass on a Shinkansen train when the last calendar day ends,
the term of the validity cannot be extended due to the happening,
but you can continue to take the same Shinkansen train, make a transfer to a JR conventional (= non-Shinkansen) line and take a rapid or Local train, as long as such a train is still available, until you go through an exit gate at a station.

Oh, yeah, sorry, the first one wasn't shinkansen, I've edited the message and forgot to edit the train type. But the train itself does exist. :)

And thanks a lot for your answers! I had a feeling I've read the exact same answer somewhere else before, but couldn't google it up.
Thank you!