Japanese calendar types have included a range of official and unofficial systems. At present, Japan uses the Gregorian calendar together with year designations stating the year of the reign of the current Emperor. The written form starts with the year, then the month and finally the day, coinciding with the ISO 8601 standard. For example, February 16, 2003, can be written as either 2003年2月16日 or 平成15年2月16日 (the latter following the regnal year system). 年 reads nen and means "year", 月 reads gatsu (がつ) and means "month" and finally 日 (usually) reads nichi (its pronunciation depends on the number that precedes it, see below) and means "day".
Prior to the introduction of the Gregorian calendar in 1873, the reference calendar was based on the lunisolar Chinese calendar.
File:Briefly_Abridged_Calendar_of_1873%2C_Hiroshige_Museum_of_Art.JPG|Briefly Abridged Calendar of 1873
File:Calendar_for_1907%2C_Nakai_Tokujiro_%28Pub.%29%2C_Hiroshige_Museum_of_Art.JPG|Calendar for 1907
Over the centuries, Japan has used up to four systems for designating years: the Chinese sexagenary cycle, the era name system, the Japanese imperial year and the Western Common Era (Anno Domini) system. In the 21st century, however, the era system (gengo) and Western system (seireki) are the only ones still widely used.
The lunisolar Chinese calendar was introduced to Japan via Korea in the middle of the sixth century. After that, Japan calculated its calendar using various Chinese calendar procedures, and from 1685, using Japanese variations of the Chinese procedures. Its sexagenary cycle was often used together with era names, as in the 1729 Ise calendar shown above, which is for "the 14th year of Kyōhō, tsuchi-no-to no tori", i.e., 己酉.
In modern times, the old Chinese calendar is virtually ignored; celebrations of the Lunar New Year are thus limited to Chinese and other Asian immigrant communities. However, its influence can still be felt in the idea of "lucky and unlucky days" (described below), the traditional meanings behind the name of each month, and other features of modern Japanese calendars.