"Calendar" table is a vague title. Common calendar mechanical watch only in the year March 1, 2100 without the need to adjust the calendar (which is still theoretically, to ensure that the watch kept walking in 83 years, but perpetual calendar watch every five years is also need to wash oil ) Why is March 1, 2100? Because today's Gregorian calendar was fine-tuned by Pope Gregory XIII in 1582 (reducing the historical error by 10 days in 1582 and eliminating the historical error by 1582, the entire hundred-year calendar after 1582 needs to be divisible by 400 to be a leap year, such as 1600 Year, 2000 is a leap year; the rest is not), so 2100 is not a leap year, in February of 2100 only 28 days. Only very few perpetual calendar watches can be identified in 2100, and very expensive. The current electronic calendar such as cell phone calendar is "calendar," but I believe that the life of electronic products is difficult to more than ten years, but can not adhere to 2100. From a heritage point of view, the calendar mechanical watch is both delicate and beautiful artwork, its life-long enough to leave your future generations as a baby or think.