The year 2000 was a special leap year. A year whose last two digits are divisible by 4 is a leap year and its days become 366 by an extra day being added.However, there is a supplemental definition for the leap year as follows:・A year whose last two digits are 00 is NOT a leap year except for the year is divisible by 400.The year 2000 has 00 as the last two digits but it is divisible by 400, making it a leap year. Consequently, the years from 1901 to 2099 is a little rare 199-year period when a leap year comes every four years with no exception. (The next period of the same kind is from 2301 to 2499, about 300 years later.)As a result, it is regarded sufficient for most of computers and other devices to be equipped with the calendar with the simple leap year rule that "A year divisible with 4 is a leap year." and that causes no problems in most cases.However, the year 2100 is not a leap year as it is divisible by 4 but not by 400 and ends with 00 and the simple rule above will become ineffective and the calendar will become incorrect.

The reason why correct date and day of week are indicated by setting a year different from actual one is as follows.An alternative year of a certain year has the same calendar as that of the latter. In other words, their January 1 has the same day of week.For example, January 1 of 2017 is Sunday and the calendar of the year can be replaced with that of 1995, which is also start from Sunday.

The calendar function of old watches may sometimes be limited (for example, from 1992 to 2004) and not cover recent years. Date and day of the week are not indicated correctly on such watches after the covered years passed.In that case, you can indicate correct date and day of week on your watch by setting a covered year which has the same calendar as that you actually want to set.The list below shows alternative years (1992 - 2004) for 2016 - 2099.Alternative year list (2016 - 2099)YearAlternative yearAlternative year from March 1YearAlternative yearAlternative year from March 1201619931994205820022017199520592003201820012060200420192002206119942020199220621995202119932063200120221994206420022003202319952065199820241996206619932025199720671994202619982068199520012027199920692002202820002070200320292001207119982030200220721993199420312003207319952032200420742001203319942075200220341995207619922035200120771993203620022003207819942037199820791995203819932080199620391994208119972040199520012082199820412002208319992042200320842000204319982085200120441993199420862002204519952087200320462001208820042047200220891994204819922090199520491993209120012050199420922002200320511995209319982052199620941993205319972095199420541998209619952001205519992097200220562000209820032057200120991998About "Alternative year from March 1"The years 2016, 2036, 2040, 2044, 2064, 2068, 2072, 2092 and 2096 are leap years. However, their alternative years are not leap years and their calendars will become unmatched with the actual ones after February 29.In those leap years, you must set another alternative year or "alternative year from March 1" after March 1.

The time of the watch is twelve-hour faster or slower.Put the time on the watch twelve-hour forward or backward.The method of time adjustment is different depending on the model.Refer to the instruction manual of the watch to make changes.・For some models, you can also use the abbreviated instruction.Instruction manualhttp://www.citizenwatch-global.com/support/guide/manual.html