In the culture of China the cyclic calendar was popular to record the date of any event on a short-term basis. In the long term, as with historical events, records stated during which year of which reign an event occurred. The following table introduces the corresponding years of the 60-year cyclic calendar in comparison to the western calendar.
In a year notation using the sexagenary or cyclical year the same year is repeated every 60 years. Each cycle is a combination of the Chinese zodiac animals (12 years) with the five elements, resulting in a cyclical repetition of each year every 60 years.
With this type of year notation it is difficult to pinpoint the exact year an antique porcelain item was made. However, if the style or features of an antique piece point to a certain reign, then the year can be determined because the date has to lie within that respective reign (period).
Due to the fact that only the Kangxi reign (1662-1722) in the Qing dynasty lasted long enough for a repetition of a year, dating is possible if both are known.
You will only seldom encounter this type of year notation in porcelain marks at the bottom of ceramics.
However, since the later part of the Qing dynasty (second half of 19th century) its usage did become more frequent, and is found mainly on the outer face of ceramic vessels. Its use is similar to that on traditional Chinese paintings. The artist writes a verse or dedication on the left side of the picture and states the year in cyclic year form at the end, sometimes the season is added. Then the artist's name, a seal mark, or both follow.
To find an earlier year than 1804 just deduct 60 years, or a multiple of 60, from the western calendar year corresponding to the characters of that specific cyclic year. The characters are always in the same order within a cycle. That is, the 25th year within a certain 60 year cycle will have the same characters as that in another cycle.
The main problem for those not reading Chinese will be the identification of the hand-written characters on the antique item by comparing with the standard font in the above table.