How long does a ticket remain valid

If I were to buy a one way ticket in the morning, would the ticket still be valid in the evening of the same day.

For example:
Let's say I buy a yamanote line ticket from shinjuku to shibuya at 6 am, can it still be used at 10pm of the same day? If not, how long does it take for the ticket to expire? Note that this question is in regards to all JR lines.

Thank you very much

Let's say I buy a yamanote line ticket from shinjuku to shibuya at 6 am, can it still be used at 10pm of the same day?
Do you mean you buy a ticket at 6am but not use until 10pm? Then, it's still valid.

Note that if you are purchasing a ticket from a regular machine at a station then that ticket is only good for entering at that station.

You can, however, specify which station you want to enter and exit at and get the proper ticket if you purchase from special machines or the station agent.

Let's say I buy a yamanote line ticket from shinjuku to shibuya at 6 am, can it still be used at 10pm of the same day?

Yes. Tickets are valid for at least one calendar day. Unless you specify otherwise, it is valid on the day you purchase it. If the ticket covers a distance of between 100 and 200 km, it is valid for two days, 200-400 km for 3 days and an additional day for every additional 200km traveled.

Thanks for the quick answers everyone