Seireki

Seireki, also known as Western calendar or Gregorian calendar, is the most widely used calendar system in the world. It was introduced in Japan in 1873, replacing the traditional Japanese calendar. The seireki system is based on the Gregorian calendar, which was established by Pope Gregory XIII in 1582. It is a solar calendar, meaning it is based on the Earth's orbit around the Sun.

The seireki system uses a 12-month structure, with each month having a varying number of days. The year starts in January and ends in December. The year is divided into four seasons: spring, summer, autumn, and winter. The seireki system also includes leap years, which occur every four years to account for the extra time it takes for the Earth to orbit the Sun.

In Japan, the seireki system is used alongside the traditional Japanese calendar, which is based on the lunar cycle. The seireki system is used for official purposes, such as government documents and business transactions, while the traditional Japanese calendar is used for cultural and religious events.

The seireki system is used in many countries around the world, including the United States, Canada, and Australia. It is the standard calendar system for most international organizations, such as the United Nations and the European Union. The seireki system is also used in many Asian countries, such as China, South Korea, and Vietnam, although they may have their own variations of the calendar system.

In summary, seireki is the most widely used calendar system in the world, based on the Gregorian calendar. It is used for official purposes in many countries and is the standard calendar system for most international organizations. The seireki system is used alongside the traditional Japanese calendar in Japan, with each calendar system serving different purposes.