The validity of a 7, 14 or 21 day JR Pass is based on calendar days (midnight to midnight), rather than 24 hour periods. For example, if you start using your pass at 2pm on day 1, it will expire at 11.59pm on day 7, rather than 2pm on day 8. If you happen to be on board a train at midnight on your last day, your JR Pass remains valid until the end of your journey.