Indian national calendar
The Indian national calendar, sometimes called the Shalivahana Shaka calendar. It is used, alongside the Gregorian calendar, by The Gazette of India, in news broadcasts by All India Radio and in calendars and communications issued by the Government of India; the Saka calendar is used in Java and Bali among Indonesian Hindus. Nyepi, the "Day of Silence", is a celebration of the Saka new year in Bali. Nepal's Nepal Sambat evolved from the Saka calendar. Prior to colonization, the Philippines used to apply the Saka calendar as well as suggested by the Laguna Copperplate Inscription; the term may ambiguously refer to the Hindu calendar. The historic Shalivahana era calendar is still used, it has years. The calendar months follow the signs of the tropical zodiac rather than the sidereal zodiac used with the Hindu calendar. Chaitra has 30 days and starts on March 22, except in leap years, when it has 31 days and starts on March 21; the months in the first half of the year all have 31 days, to take into account the slower movement of the sun across the ecliptic at this time.
The names of the months are derived from older, Hindu lunisolar calendars, so variations in spelling exist, there is a possible source of confusion as to what calendar a date belongs to. Years are counted in the Saka era. To determine leap years, add 78 to the Saka year – if the result is a leap year in the Gregorian calendar the Saka year is a leap year as well, its structure is just like the Persian calendar. Senior Indian Astrophysicist Meghnad Saha was the head of the Calendar Reform Committee under the aegis of the Council of Scientific and Industrial Research. Other members of the Committee were: A. C. Banerjee, K. K. Daftari, J. S. Karandikar, Gorakh Prasad, R. V. Vaidya and N. C. Lahiri, it was Saha's effort. The task before the Committee was to prepare an accurate calendar based on scientific study, which could be adopted uniformly throughout India, it was a mammoth task. The Committee had to undertake a detailed study of different calendars prevalent in different parts of the country. There were thirty different calendars.
The task was further complicated by the fact that religion and local sentiments were integral to those calendars. India's first prime minister, Jawaharlal Nehru, in his preface to the Report of the Committee, published in 1955, wrote: “They represent past political divisions in the country.... Now that we have attained Independence, it is desirable that there should be a certain uniformity in the calendar for our civic and other purposes, this should be done on a scientific approach to this problem.” Usage started at 1 Chaitra 1879, Saka Era, or 22 March 1957. Report of the Calendar Reform Committee – online link. Mapping Time: The Calendar and its History by E. G. Richards, 1998, pp. 184–185. Calendars and their History Indian Calendars Positional astronomy in India Indian National Calendar abstract
As a means of recording the passage of time, the 14th century was a century lasting from January 1, 1301, to December 31, 1400. During this period and natural disasters ravaged both Europe and the four khanates of the Mongol Empire; the Mongol court was driven out of China and retreated to Mongolia, the Ilkhanate collapsed in Persia, the Chaghatayid dissolved and broke into two parts, the Golden Horde lost its position as a great power in Eastern Europe. In Europe, the Black Death claimed between 75 and 200 million lives – wiping out over 60 percent of European society – while England and France fought in the protracted Hundred Years' War after the death of Charles IV, King of France led to a claim to the French throne by Edward III, King of England; this period is considered the height of chivalry and marks the beginning of strong separate identities for both England and France. The transition from the Medieval Warm Period to the Little Ice Age. Beginning of the Ottoman Empire, early expansion into the Balkans.
Early 14th century: Attributed to Kao Ninga Monk Sewing is made. Kamakura period, it is now kept at The Cleveland Museum of Art. An account of Buddha's life, translated earlier into Greek by Saint John of Damascus and circulated to Christians as the story of Barlaam and Josaphat, became so popular that the two were venerated as saints. Singapore emerges for the first time as a fortified trading centre of some importance. Islam reaches Terengganu, on the Malay Peninsula; the Hausa found several city-states in the south of modern Niger. The poet Petrarch coins the term Dark Ages to describe the preceding 900 years in Europe, beginning with the fall of the Western Roman Empire in 476 through to the renewal embodied in the Renaissance. Iwan vault, Jamé Mosque of Isfahan, Persia, is built. Work begins on the Great Enclosure at Great Zimbabwe, built of dressed stone; the city's population is now between 10,000 and 40,000. 1309 — King Jayanegara succeeds Kertarajasa Jayawardhana as ruler of Majapahit. 1309-1377 — The Avignon papacy transfers the seat of the Popes from Italy to France The Great Famine of 1315-1317 kills millions of people in Europe.
1318-1330 — An Italian Franciscan friar, Mattiussi visited Sumatra and Banjarmasin in Borneo. In his record he described the kingdom of Majapahit. 1320 — Władysław I the Elbow-high is crowned King of Poland which leads to its unification 1323 — Malietoafaiga ordered cannibalism to be abolished in Tutuila, now known as American Samoa. 1325 — Forced out of previous locations, the Mexica found the city of Tenochtitlan 1328 — Tribhuwana Wijayatunggadewi succeeds Jayanegara as ruler of Majapahit. Beginning of the Renaissance in Italy 1335 — The death of the Ilkhan Abu Said, causes the disintegration of the Mongol rule in Persia. 1336 — The Vijayanagara Empire is founded in South India by Harihara 1337 — The Hundred Years' War begins when Edward III of England lays claim to the French throne. 1345–1346 — The French recruit troops and ships in Genoa and Nice. 1346 — English forces led by Edward III defeat a French army led by Philip VI in The Battle of Crécy, a major point in the Hundred Years' War which marks the rise of the longbow as a dominant weapon in Western Europe.
1347–1351 — The Black Death kills around a third of the population of Europe. 1347 — Adityawarman moved the capital of Dharmasraya and established the kingdom of Malayupura in Pagarruyung, West Sumatra. 1350 — Hayam Wuruk, styled Sri Rajasanagara, succeeds Tribhuwana Wijayatunggadewi as ruler of Majapahit. Under its military commander Gajah Mada, Majapahit stretches over much of modern-day Indonesia. 1356 — The Imperial Diet of the Holy Roman Empire headed by Emperor Charles IV issues the Golden Bull of 1356, establishing various constitutional aspects of the Empire, the most significant being the electoral college to elect future emperors. 1356 — The Diet of the Hansa is held in Lübeck, formalising what up until had only been a loose alliance of trading cities in northern Europe and founding the Hanseatic League. 1357 — Scotland retains its independence with the signing of the Treaty of Berwick, thus ending the Wars of Scottish Independence. 1357 — In the Battle of Bubat, the Sundanese royal family is massacred by the Majapahit army by the order of Gajah Mada.
1363 — The Battle of Lake Poyang, a naval conflict between Chinese rebel groups led by Chen Youliang and Zhu Yuanzhang, takes place from August to October, constituting one of the largest naval battles in history. 1365 — The Old Javanese text Nagarakertagama is written. 1366 — Tepanec Tlatoani Acolnahuácatl accepts Acamapichtli as the first tlatoani of Tenochtitlan for the Mexica Empire. 1368 — The end of the Mongol Yuan Dynasty in China and the beginning of the Ming Dynasty. 1377 — Majapahit sends a punitive expedition against Palembang in Sumatra. Palembang's prince, Parameswara flees finding his way to Malacca and establishing it as a major international port. 1378 — The Great Schism of the West begins leading to 3 simultaneous popes. 1378-1382 — Ciompi Revolt occurs in Florence 1381 — John Wycliffe is dismissed from the University of Oxford for criticism of the Roman Catholic Church thus, the Lollardy movement rises in England. 1381 — Peasants' Revolt in England. 1385 — Battle of Aljubarrota between Portugal and Castile.
Portugal maintains independence. 1385 — Union of Krewo between Poland and Lithuania. 1389 — Battle of Kosovo between Serbs and Ottoman Turks, Prince Lazar, sultan Murat I and Miloš Obilić were killed. 1389 — Wikramawardhana succeeds Sri Rajasanagara as ruler of Majapahit. 1392 — Taejo
Kali Yuga in Hinduism is the last of the four stages the world goes through as part of a'cycle of yugas' described in the Sanskrit scriptures. The other ages are called Satya Yuga, Treta Yuga, Dvapara Yuga. Kali Yuga is associated with the demon Kali; the "Kali" of Kali Yuga means "strife", "discord", "quarrel" or "contention". According to Puranic sources, Krishna's departure marks the end of Dvapara Yuga and the start of Kali Yuga, dated to 17/18 February 3102 BCE. According to the Surya Siddhanta, Kali Yuga began at midnight on 18 February 3102 BCE; this is considered the date on which Lord Krishna left the earth to return to Vaikuntha. This information is placed at the temple of the place of this incident. According to the astronomer and mathematician Aryabhatta the Kali Yuga started in 3102 BCE, he finished his book "Aryabhattiya" in 499 CE, in which he gives the exact year of the beginning of Kali Yuga. He writes that he wrote the book in the "year 3600 of the Kali Age" at the age of 23; as it was the 3600th year of the Kali Age when he was 23 years old, given that Aryabhatta was born in 476 CE, the beginning of the Kali Yuga would come to 3102 BCE.
According to KD Abhyankar, the starting point of Kali Yuga is an rare planetary alignment, depicted in the Mohenjo-Daro seals. Going by this alignment the year 3102 BCE is off; the actual date for this alignment is 7 February of 3104 BCE. There is sufficient proof to believe that Vrdhha Garga knew of precession at least by 500 BCE. Garga had calculated the rate of precession to within 30 % of; the common belief until Swami Sri Yukteswar Giri had analyzed the dating of the Yuga cycles was that the Kali Yuga would last for 432,000 years after the end of the Dwapara Yuga. This originated during the puranic times when the famous astronomer Aryabhatta recalculated the timeline by artificially inflating the traditional 12,000 year figure with a multiplication of 360, represented as the number of "human years" that make up a single "divine year"; this was a purposeful miscalculation due to conflicts with one of the preeminent astronomer of the time Brahmagupta. However, both the Mahabharata and the Manu Smriti have the original value of 12,000 years for one half of the Yuga cycle.
Contemporary analysis of historical data from the last 11 millennia matches with the indigenous Saptarishi Calendar. The length of the transitional periods between each Yuga is unclear, can only be estimated based on historical data of past cataclysmic events. Using a 300 year period for transitions, Kali Yuga has either ended in the past 100 to 200 years, or is to end soon sometime in the next 100 years. Other authors, such as the revered Hindu guru Swami Sri Yukteswar in his book The Holy Science, as well as the influential Yogi Paramhansa Yogananda, believe that the Kali Yuga has ended, that we are now in an ascending Dvapara Yuga; this calculation is supported by modern day spiritual masters such as Sadhguru Jaggi Vasudev. Hindus believe that human civilization degenerates spiritually during the Kali Yuga, referred to as the Dark Age because in it people are as far away as possible from God. Hinduism symbolically represents morality as an Indian bull. Common attributes and consequences are spiritual bankruptcy, mindless hedonism, breakdown of all social structure and materialism, unrestricted egotism and maladies of mind and body.
In Satya Yuga, the first stage of development, the bull has four legs, but in each age morality is reduced by one quarter. By the age of Kali, morality is reduced to only a quarter of that of the golden age, so that the bull of Dharma has only one leg; the Mahabharata War and the decimation of Kauravas thus happened at the "Yuga-Sandhi", the point of transition from one yuga to another. The scriptures mention Sage Narada to have momentarily intercepted the demon Kali on his way to the Earth when Duryodhana was about to be born in order to make him an embodiment of arishadvargas and adharma in preparation of the era of decay in values and the consequent havoc. A discourse by Markandeya in the Mahabharata identifies some of the attributes of Kali Yuga. In relation to rulers, it lists: Rulers will become unreasonable: they will levy taxes unfairly. Rulers will no longer see it as their duty to promote spirituality, or to protect their subjects: they will become a danger to the world. People will start seeking countries where wheat and barley form the staple food source.
"At the end of Kali-yuga, when there exist no topics on the subject of God at the residences of so-called saints and respectable gentlemen of the three higher varnas and when nothing is known of the techniques of sacrifice by word, at that time the Lord will appear as the supreme chastiser." (Srimad-Bhagavatam With regard to human relationships, Markandeya's discourse says: Avarice and wrath will be common. Humans will display animosity towards each other. Ignorance of dharma will occur. People will see nothing wrong in that. Lust will be viewed as acceptable and sexual intercourse will be seen as the central requirement of life. Sin will increase exponentially, while virtue will cease to flourish. People will become addicted to intoxicating drugs. Gurus will no longer be respected and their students will attempt
The 12th century is the period from 1101 to 1200 in accordance with the Julian calendar in the Common Era. In the history of European culture, this period is considered part of the High Middle Ages and is sometimes called the Age of the Cistercians. In Song dynasty China an invasion by Jurchens caused a political schism of south; the Khmer Empire of Cambodia flourished during this century, while the Fatimids of Egypt were overtaken by the Ayyubid dynasty. China is under the Northern Song dynasty. Early in the century, Zhang Zeduan paints Along the River During the Qingming Festival, it will end up in the Palace Museum, Beijing. In southeast Asia, there is conflict between the Champa. Angkor Wat is built under the Hindu king Suryavarman II. By the end of the century the Buddhist Jayavarman VII becomes the ruler. Japan is in its Heian period; the Chōjū-jinbutsu-giga is made and attributed to Toba Sōjō. It ends up at the Kyoto. In Oceania, the Tuʻi Tonga Empire expands to a much greater area. Europe undergoes the Renaissance of the 12th century.
The blast furnace for the smelting of cast iron is imported from China, appearing around Lapphyttan, Sweden, as early as 1150. Alexander Neckam is the first European to document the mariner's compass, first documented by Shen Kuo during the previous century. Christian humanism becomes a self-conscious philosophical tendency in Europe. Christianity is introduced to Estonia and Karelia; the first medieval universities are founded. Pierre Abelard teaches. Middle English begins to develop, literacy begins to spread outside the Church throughout Europe. In addition, churchmen are willing to take on secular roles. By the end of the century, at least a third of England's bishops act as royal judges in secular matters; the Ars antiqua period in the history of the classical music of Western Europe begins. The earliest recorded miracle play is performed in England. Gothic architecture and trouvère music begin in France. During the middle of the century, the Cappella Palatina is built in Palermo and the Madrid Skylitzes manuscript illustrates the Synopsis of Histories by John Skylitzes.
Fire and plague insurance first become available in Iceland, the first documented outbreaks of influenza there happens. The medieval state of Serbia is formed by Stefan Nemanja and continued by the Nemanjić dynasty. By the end of the century, both the Capetian Dynasty and the House of Anjou are relying on mercenaries in their militaries. Paid soldiers are available year-round, unlike knights who expected certain periods off to maintain their manor lifestyles. In India, Hoysala architecture reaches a peak. In the Middle East, the icon of Theotokos of Vladimir is painted in Constantinople. Everything but the faces will be retouched, the icon will go to the Tretyakov Gallery of Moscow; the Georgian poet Shota Rustaveli composes his epic poem The Knight in the Panther's Skin. Shahab al-Din Suhrawardi founds his "school of illumination". In North Africa, the kasbah of Marrakesh is built, including the city gate Bab Agnaou and the Koutoubia mosque. In sub-Saharan Africa, Kente cloth is first woven. In France, the first piedfort coins in the history of numismatics were minted.
The city of Tula burns down, marking the end of the Toltec Empire List of 12th-century inventions 1104—The Venice Arsenal of Venice, Italy, is founded. It employed some 16,000 people for the mass production of sailing ships in large assembly lines, hundreds of years before the Industrial Revolution. 1106—Finished building of Gelati. 1107—The Chinese engineer Wu Deren combines the mechanical compass vehicle of the south-pointing chariot with the distance-measuring odometer device. 1111—The Chinese Donglin Academy is founded. 1165—The Liuhe Pagoda of Hangzhou, China, is built. 1170—The Christian notion of Purgatory is defined. 1185—First record of windmills. 1100: On August 5, Henry I is crowned King of England. 1100: On December 25, Baldwin of Boulogne is crowned as the first King of Jerusalem in the Church of the Nativity in Bethlehem. 1101: In July, the Treaty of Alton is signed between Henry I of England and his older brother Robert, Duke of Normandy in which Robert agrees to recognize Henry as king of England in exchange for a yearly stipend and other concessions.
The agreement temporarily ends a crisis in the succession of the Anglo-Norman kings. 1101–1103: David the Builder takes over Kakheti and Hereti. 1102: King Coloman unites Hungary and Croatia under the Hungarian Crown. 1102: Muslims conquer Señorio de Valencia 1103-1104: A church council is convened by King David the Builder in Urbnisi to reorganize the Georgian Orthodox Church. 1104: In the Battle of Ertsukhi, King David the Builder defeats an army of Seljuks. 1104: King Jayawarsa of Kadiri ascends to the throne. 1106: Battle of Tinchebray 1107–1111: Sigurd I of Norway becomes the first Norwegian king to embark on a crusade to the Holy Land. He fights in Lisbon and on various Mediterranean isles, helps the King of Jerusalem to take Sidon from the Muslims. 1108: By the Treaty of Devol, signed in September, Bohemond I of Antioch has to submit to the Byzantine Empire, becoming the vassal of Alexius I. 1109: On June 10, Bertrand of Toulouse captures the County of Tripoli. 1109: In the Battle of Nakło, Boleslaus III Wrymouth defeats the Pomeranians and re-establishes Polish access to the sea.
1109: On August 24, in the Battle of Hundsfeld, Boleslaus III Wrymouth defeats Emperor Henry V of Germany and stops German expansion eastward. 1111: On April 14, during Henry V's first expedition to Rome, he is crowned Holy Roman Emperor. 1113: Paramavishnulok is crowned as King Suryavarman II in Cambodia. He expands the Khmer Empire and builds Angkor Wat
The traditional China calendar, or Former Calendar, Traditional Calendar or Lunar Calendar, is a lunisolar calendar which reckons years and days according to astronomical phenomena. It is defined by GB/T 33661-2017, "Calculation and promulgation of the Chinese calendar", issued by the Standardisation Administration of China on 12 May 2017. Although modern day China uses the Gregorian calendar, the traditional Chinese calendar governs holidays in China and in overseas Chinese communities, it lists the dates of traditional Chinese holidays and guides people in selecting auspicious days for weddings, moving, or starting a business. Like Chinese characters, variants of this calendar are used in different parts of the Chinese cultural sphere. Korea and the Ryukyu Islands adopted the calendar, it evolved into Korean and Ryukyuan calendars; the main difference from the traditional Chinese calendar is the use of different meridians, which leads to some astronomical events—and calendar events based on them—falling on different dates.
The traditional Japanese calendar derived from the Chinese calendar, but its official use in Japan was abolished in 1873 as part of reforms after the Meiji Restoration. Calendars in Mongolia and Tibet have absorbed elements of the traditional Chinese calendar, but are not direct descendants of it. Days begin and end at midnight, months begin on the day of the new moon. Years begin on the second new moon after the winter solstice. Solar terms govern the end of each month. Written versions in ancient China included stems and branches of the year and the names of each month, including leap months as needed. Characters indicated whether a month was short; the traditional Chinese calendar was developed between 771 and 476 BC, during the Spring and Autumn period of the Eastern Zhou dynasty. Before the Zhou dynasty, solar calendars were used. One version of the solar calendar is the five-elements calendar. A 365-day year was divided into five phases of 73 days, with each phase corresponding to a Day 1 Wu Xing element.
A phase began followed by six 12-day weeks. Each phase consisted of two three-week months. Years began followed by a bǐngzǐ day and a 72-day fire phase. Other days were tracked using the Yellow River Map. Another version is a four-quarters calendar. Weeks were ten days long, with one month consisting of three weeks. A year had 12 months, with a ten-day week intercalated in summer as needed to keep up with the tropical year; the 10 Heavenly Stems and 12 Earthly Branches were used to mark days. A third version is the balanced calendar. A year was 365.25 days, a month was 29.5 days. After every 16th month, a half-month was intercalated. According to oracle bone records, the Shang dynasty calendar was a balanced calendar with 12 to 14 months in a year; the first lunisolar calendar was the Zhou calendar, introduced under the Zhou dynasty. This calendar set the beginning of the year at the day of the new moon before the winter solstice, it set the shàngyuán as the winter solstice of a dīngsì year, making the year it was introduced around 2,758,130.
Several competing lunisolar calendars were introduced by states fighting Zhou control during the Warring States period. The state of Lu issued its own Lu calendar. Jin issued the Xia calendar in AD 102, with a year beginning on the day of the new moon nearest the March equinox. Qin issued the Zhuanxu calendar, with a year beginning on the day of the new moon nearest the winter solstice. Song's Yin calendar began its year on the day of the new moon after the winter solstice; these calendars are known as the six ancient calendars, or quarter-remainder calendars, since all calculate a year as 365 1⁄4 days long. Months begin on the day of the new moon, a year has 12 or 13 months. Intercalary months are added to the end of the year; the Qiang and Dai calendars are modern versions of the Zhuanxu calendar, used by mountain peoples. After Qin Shi Huang unified China under the Qin dynasty in 221 BC, the Qin calendar was introduced, it followed most of the rules governing the Zhuanxu calendar, but the month order was that of the Xia calendar.
The intercalary month, known as the second Jiǔyuè, was placed at the end of the year. The Qin calendar was used into the Han dynasty. Emperor Wu of Han r. 141 – 87 BC introduced reforms halfway through his reign. His Taichu Calendar defined a solar year as 365 385⁄1539 days, the lunar month was 29 43⁄81 days; this calendar introduced the 24 solar terms. Solar terms were paired, with the 12 combined periods known as climate terms; the first solar term of the period was known as a pre-climate, the second was a mid-climate. Months were named for the mid-climat
The Republic of China calendar is the official calendar of the Republic of China. It is used to number the years for official purposes only in the Taiwan area after 1949, it was used in the Chinese mainland from 1912 until the establishment of the People's Republic of China in 1949. Following the Chinese imperial tradition of using the sovereign's era name and year of reign, official ROC documents use the Republic system of numbering years in which the first year was 1912, the year of the establishment of the Republic of China. Months and days are numbered according to the Gregorian calendar; the Gregorian calendar was adopted by the nascent Republic of China effective 1 January 1912 for official business, but the general populace continued to use the traditional Chinese calendar. The status of the Gregorian calendar was unclear between 1916 and 1921 while China was controlled by several competing warlords each supported by foreign colonial powers. From about 1921 until 1928 warlords continued to fight over northern China, but the Kuomintang or Nationalist government controlled southern China and used the Gregorian calendar.
After the Kuomintang reconstituted the Republic of China on 10 October 1928, the Gregorian calendar was adopted, effective 1 January 1929. The People's Republic of China has continued to use the Gregorian calendar since 1949. Despite the adoption of the Gregorian calendar, the numbering of the years was still an issue; the Chinese imperial tradition was to use the emperor's era year of reign. One alternative to this approach was to use the reign of the half-historical, half-legendary Yellow Emperor in the third millennium BC to number the years. In the early 20th century, some Chinese Republicans began to advocate such a system of continuously numbered years, so that year markings would be independent of the Emperor's regnal name; when Sun Yat-sen became the provisional president of the Republic of China, he sent telegrams to leaders of all provinces and announced the 13th day of 11th Month of the 4609th year of the Yellow Emperor's reign to be the first year of the Republic of China. The original intention of the Minguo calendar was to follow the imperial practice of naming the years according to the number of years the Emperor had reigned, a universally recognizable event in China.
Following the establishment of the Republic, hence the lack of an Emperor, it was decided to use the year of the establishment of the current regime. This reduced the issue of frequent change in the calendar, as no Emperor ruled more than 61 years in Chinese history — the longest being the Kangxi Emperor, who ruled from 1662–1722; as Chinese era names are traditionally two characters long, 民國 is employed as an abbreviation of 中華民國. The first year, 1912, is called 民國元年 and 2010, the "99th year of the Republic" is 民國九十九年, 民國99年, or 99. Based on Chinese National Standard CNS 7648: Data Elements and Interchange Formats—Information Interchange—Representation of Dates and Times, year numbering may use the Gregorian system as well as the ROC era. For example, 3 May 2004 may be written 2004-05-03 or ROC 93-05-03; the ROC era numbering happens to be the same as the numbering used by the Juche calendar of North Korea, because its founder, Kim Il-sung, was born in 1912. The years in Japan's Taishō period coincide with those of the ROC era.
In addition to the ROC's Minguo calendar, Taiwanese continue to use the lunar Chinese calendar for certain functions such as the dates of many holidays, the calculation of people's ages, religious functions. The use of the ROC era system extends beyond official documents. Misinterpretation is more in the cases when the prefix is omitted. There have been legislative proposals by pro-Taiwan Independence political parties, such as the Democratic Progressive Party to abolish the Republican calendar in favor of the Gregorian calendar. To convert any Gregorian calendar year between 1912 and the current year to Minguo calendar, 1912 needs to be subtracted from the year in question 1 added. East Asian age reckoning Public holidays in Taiwan
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 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, from 1685, using Japanese variations of the Chinese procedures, but in 1873, as part of Japan's Meiji period modernization, a calendar based on the solar Gregorian calendar was introduced. In Japan today, the old Chinese calendar is ignored. Japan has had more than one system for designating years. Including: The Chinese sexagenary cycle was introduced early into Japan, it was used together with era names, as in the 1729 Ise calendar shown above, for "the 14th year of Kyōhō, tsuchi-no-to no tori", i.e. 己酉. Now, the cycle is used except around New Year; the era name system was introduced from China, has been in continuous use since AD 701.
Since the Taishō Emperor's ascension in 1912, each emperor's reign has begun a new era. Nengō are the official means of dating years in Japan, all government business is conducted using that system, it is in general use in private and personal business. The Japanese imperial year is based on the date of the legendary founding of Japan by Emperor Jimmu in 660 BC, it was first used in the official calendar in 1873. However, it never replaced era names, since World War II has been abandoned; the Western Common Era system has come into common use since the Meiji period. Now, most people know it, as well as era names; the official dating system known as nengō, has been in use since the late 7th century. Years are numbered within eras. Beginning with Meiji, each reign has been one era, but many earlier Emperors decreed a new era upon any major event; the nengō system remains in wide use on official documents and government forms. The imperial year system was used from 1872 to the Second World War. Imperial year 1 was the year when the legendary Emperor Jimmu founded Japan – 660 BC according to the Gregorian Calendar.
Usage of kōki dating can be a nationalist signal, pointing out that the history of Japan's imperial family is longer than that of Christianity, the basis of the Anno Domini system. Kōki 2600 was a special year; the 1940 Summer Olympics and Tokyo Expo were planned as anniversary events, but were canceled due to the Second Sino-Japanese War. The Japanese naval Zero Fighter was named after this year. After the Second World War, the United States occupied Japan, stopped the use of kōki by officials. Today, kōki is used, except in some judicial contexts; the 1898 law determining the placement of leap years is based on the kōki years, using a formula, equivalent to that of the Gregorian calendar: if the kōki year number is evenly divisible by four, it is a leap year, unless the number minus 660 is evenly divisible by 100 and not by 400. Thus, for example, the year Kōki 2560 is divisible by 4; the Japanese government has announced a new period of year on 2019 April Reiwa. The Heisei Period will end on 2019 April 30 and so the new period of year is expected to start on first of May 2019.
See "Seasonal days", below. The modern Japanese names for the months translate to "first month", "second month", so on; the corresponding number is combined with the suffix 月. The table below uses traditional numerals. In addition, every month has a traditional name, still used by some in fields such as poetry; the opening paragraph of a letter or the greeting in a speech might borrow one of these names to convey a sense of the season. Some, such as Yayoi and Satsuki, do double duty as given names; these month names appear from time to time on jidaigeki, contemporary television shows and movies set in the Edo period or earlier. The old Japanese calendar was an adjusted lunar calendar based on the Chinese calendar, the year—and with it the months—started anywhere from about 3 to 7 weeks than the modern year, so in historical contexts it is not accurate to equate the first month with January. Japan uses a seven-day week, aligned with the Western calendar; the seven-day week, with names for the days corresponding to the Latin system, was brought to Japan around AD 800 with the Buddhist calendar.
The system was used for astrological purposes and little else until 1876. The names of the days come from the five visible planets, which in turn are named after the five Chinese elements, from the moon and sun. On the origin of the names of the days of the week see East Asian Seven Luminaries. Sunday and Saturday are regarded as "Western style take-a-rest days". Since the late 19th century, Sunday has been regarded as a "full-time holiday", Saturday a half-time holiday; these holidays have no religious meaning. Many Japanese retailers