Purchasing/Reserving Train Ticket?

Question:

Hi, I want to know if for instance, I want to purchase a train ticket for reserved seat in advance, will the ticket be applicable only to a specific departure time and would no longer be used if I missed the indicated departure time? Because accdng. to Japan-guide, reservation only requires "departure date" but not time?

thank you!

Answer:

>will the ticket be applicable only to a specific departure time and would no longer be used if I missed the indicated departure time?

Yes. Or you should say it's applicable only to a "specific train"

Addition:
>and for trains that require reservation, one has to proceed to a manned ticket booth/office rather than a simple ticket machine right?

It's the most common way. But you can reserve it also on a machine or online.