Japan follows the Japan Standard Time (JST). The 12 hour and 24 hour notations are applied throughout Japan. Schedules, such as for trains or flights are often noted in the 24-hour notation. Japan does not follow Daylight Savings Time, though it has been the topic of discussion many times. Japan follows the standard UTC (Coorinated Universal Time) time plus 9 hours year round. It was often referred to as Tokyo Standard Time during World War 2.
In the past when the time zones were being given, each city had a different time zone where when the sun was directly overhead then it would be noon. Eventually this became an issue and was changed to better suit things like train transportation.
