Republic of China (1912–1949)
The Republic of China controlled the Chinese mainland between 1912 and 1949. It was established in January 1912 after the Xinhai Revolution, which overthrew the Qing dynasty, the last imperial dynasty of China, its government moved to Taipei in December 1949 due to the Kuomintang's defeat in the Chinese Civil War. The Republic's first president, Sun Yat-sen, served only before handing over the position to Yuan Shikai, leader of the Beiyang Army, his party led by Song Jiaoren, won the parliamentary election held in December 1912. Song Jiaoren was assassinated shortly after and the Beiyang Army led by Yuan Shikai maintained full control of the Beiyang government. Between late 1915 and early 1916, Yuan Shikai tried to reinstate the monarchy before abdicating due to popular unrest. After Yuan Shikai's death in 1916, members of cliques in the Beiyang Army claimed their autonomy and clashed with each other. During this period, the authority of the Beiyang government was weakened by a restoration of the Qing dynasty.
In 1921, Sun Yat-sen's Kuomintang established a rival government in Canton City, Canton Province, together with the fledgling Communist Party of China. The economy of North China, overtaxed to support warlord adventurism, collapsed between 1927 and 1928. General Chiang Kai-shek, who became KMT leader after Sun Yat-sen's death, started the Northern Expedition military campaign in 1926 to overthrow the Beiyang government, completed in 1928. In April 1927, Chiang established a nationalist government in Nanking, massacred communists in Shanghai, which forced the CPC into armed rebellion, marking the beginning of the Chinese Civil War. There were industrialization and modernization, but conflict between the Nationalist government in Nanking, the CPC, remnant warlords, the Empire of Japan. Nation-building took a backseat to the Second Sino-Japanese War when the Imperial Japanese Army launched an offensive against China in 1937 that turned into a full-scale invasion. After the surrender of Japan at the end of World War II in 1945, the Chinese Civil War resumed in 1946 between the KMT and CPC, with both sides receiving foreign assistance due to the Cold War from the USA and USSR, respectively.
During this period, the 1946 Constitution of the Republic of China replaced the 1928 Organic Law as the Republic's fundamental law. Near the end of the Chinese Civil War in 1949, the Chinese Communist Party established the People's Republic of China, overthrowing the nationalist government on the Chinese mainland; the Government of the Republic of China moved from Nanking to Taipei in 1949, controlling only the Taiwan area after 1949. The official name of the state in the mainland was the "Republic of China". Shortly after the ROC's establishment in 1912, while it was still located on the Chinese mainland, the government used the short form "China" to refer to itself, which derives from zhōng and guó, a term which developed under the Zhou dynasty in reference to its royal demesne, the name was applied to the area around Luoyi during the Eastern Zhou and to China's Central Plain before being used as an occasional synonym for the state during the Qing era; the ROC used alternate names throughout its existence were Republican China or Republican Era, as well as the Beiyang government, the Nationalist government.
A republic was formally established on 1 January 1912 following the Xinhai Revolution, which itself began with the Wuchang Uprising on 10 October 1911 overthrowing the Qing dynasty and ending over two thousand years of imperial rule in China. From its founding until 1949 it was based on mainland China. Central authority waxed and waned in response to warlordism, Japanese invasion, a full-scale civil war, with central authority strongest during the Nanjing Decade, when most of China came under the control of the Kuomintang under an authoritarian one-party military dictatorship. At the end of World War II in 1945, the Empire of Japan surrendered control of Taiwan and its island groups to the Allies, Taiwan was placed under the Republic of China's administrative control; the communist takeover of mainland China in the Chinese Civil War in 1949 left the ruling Kuomintang with control over only Taiwan, Kinmen and other minor islands. With the 1949 loss of mainland China in the civil war, the ROC government retreated to Taiwan and the KMT declared Taipei the provisional capital.
The Communist Party of China took over all of mainland China and founded the People's Republic of China in Beijing. In 1912, after over two thousand years of imperial rule, a republic was established to replace the monarchy; the Qing dynasty that preceded the republic experienced a century of instability throughout the 19th century, suffered from both internal rebellion and foreign imperialism. The ongoing instability led to the outburst of Boxer Rebellion in 1900, whose attacks on foreigners led to the invasion by the Eight Nation Alliance. China signed the Boxer Protocol and paid a large indemnity to the foreign powers: 450 million taels of fine silver. A program of institutional reform proved too late. Only the lack of an alternative regime prolonged its existence until 1912; the establishment of the Chinese Republic developed out of the Wuchang Uprising against the Qing government on 10 October 1911. That date is now celebrated annually as the ROC's national day known as the "Double Ten Day".
On 29 December 1911, Sun Yat-sen was elected president b
The Byzantine calendar called "Creation Era of Constantinople" or "Era of the World", was the calendar used by the Eastern Orthodox Church from c. 691 to 1728 in the Ecumenical Patriarchate. It was the official calendar of the Byzantine Empire from 988 to 1453, of Kievan Rus' and Russia from c. 988 to 1700. Since "Byzantine" is a historiographical term, the original name uses the noun "Roman" as it was how the Eastern Roman Empire continued calling itself; the calendar was based on the Julian calendar, except that the year started on 1 September and the year number used an Anno Mundi epoch derived from the Septuagint version of the Bible. It placed the date of creation at 5509 years before the Incarnation, was characterized by a certain tendency, a tradition among Jews and early Christians to number the years from the calculated foundation of the world, its Year One, marking the supposed date of creation, was September 1, 5509 BC, to August 31, 5508 BC. It is not known when; the first appearance of the term is in the treatise of a certain "monk and priest", who mentions all the main variants of the "World Era" in his work.
Georgios argues that the main advantage of the World era is the common starting point of the astronomical lunar and solar cycles, of the cycle of indictions, the usual dating system in Byzantium since the 6th century. He already regards it as the most convenient for the Easter computus. Complex calculations of the 19-year lunar and 28-year solar cycles within this world era allowed scholars to discover the cosmic significance of certain historical dates, such as the birth or the crucifixion of Jesus; this date underwent minor revisions before being finalized in the mid-7th century, although its precursors were developed c. AD 412. By the second half of the 7th century, the Creation Era was known in Western Europe, at least in Great Britain. By the late 10th century around AD 988, when the era appears in use on official government records, a unified system was recognized across the Eastern Roman world; the era was calculated as starting on September 1, Jesus was thought to have been born in the year 5509 since the creation of the world.
Historical time was thus calculated from the creation, not from Christ's birth, as in the west after the Anno Domini system was adopted between 6th and 9th centuries. The Eastern Church avoided the use of the Anno Domini system of Dionysius Exiguus, since the date of Christ's birth was debated in Constantinople as late as the 14th century. Otherwise the Byzantine calendar was identical to the Julian Calendar except that: the names of the months were transcribed from Latin into Greek; the leap day of the Byzantine calendar was obtained in an identical manner to the bissextile day of the original Roman version of the Julian calendar, by doubling the sixth day before the calends of March, i.e. by doubling 24 February. The Byzantine World Era was replaced in the Orthodox Church by the Christian Era, utilized by Patriarch Theophanes I Karykes in 1597, afterwards by Patriarch Cyril Lucaris in 1626, formally established by the Church in 1728. Meanwhile, as Russia received Orthodox Christianity from Byzantium, she inherited the Orthodox Calendar based on the Byzantine Era.
After the collapse of the Byzantine Empire in 1453, the era continued to be used by Russia, which witnessed millennialist movements in Moscow in AD 1492. It was only in AD 1700 that the Byzantine World Era in Russia was changed to the Julian Calendar by Peter the Great, it still forms the basis of traditional Orthodox calendars up to today. September AD 2000 began the year 7509 AM; the earliest extant Christian writings on the age of the world according to the Biblical chronology are by Theophilus, the sixth bishop of Antioch from the Apostles, in his apologetic work To Autolycus, by Julius Africanus in his Five Books of Chronology. Both of these early Christian writers, following the Septuagint version of the Old Testament, determined the age of the world to have been about 5,530 years at the birth of Christ. Ben Zion Wacholder points out that the writings of the Church Fathers on this subject are of vital significance, in that through the Christian chronographers a window to the earlier Hellenistic biblical chronographers is preserved: An immense intellectual effort was expended during the Hellenistic period by both Jews and pagans to date creation, the flood, building of the Temple...
In the course of their studies, men such as Tatian of Antioch, Clement of Alexandria, Hippolytus of Rome
Vikram Samvat. It uses solar sidereal years; the Vikram Samvat is notable because many medieval era inscriptions use it. It is said to be named after the legendary king Vikramaditya, but the term "Vikrama Samvat" does not appear in the historical records before the 9th century, rather the same calendaring system is found by other names such as Krita and Malava. In the colonial era scholarship, the era was believed to be based on the commemoration of King Vikramaditya expelling the Sakas from Ujjain; however epigraphical evidence and scholarship suggest that this theory has no historical basis and likely was an error. Starting in the 9th century and thereafter, epigraphical artwork uses Vikrama-Samvat, suggesting that sometime around the 9th-century, the Hindu calendar era, in use became popular as Vikram Samvat, while Buddhist and Jain epigraphy continued to use an era based on the Buddha or the Mahavira. According to popular tradition, the legendary king Vikramaditya of Ujjain established the Vikrama Samvat era after defeating the Śakas.
Kalakacharya Kathanaka by the Jain sage Mahesarasuri gives the following account: Gandharvasena, the then-powerful king of Ujjain, abducted a nun called Sarasvati, the sister of the monk. The enraged monk sought the help of the Śaka ruler King Sahi in Sistan. Despite heavy odds but aided by miracles, the Śaka king defeated Gandharvasena and made him a captive. Sarasvati was repatriated; the defeated king retired to the forest. His son, being brought up in the forest, had to rule from Pratishthana. On, Vikramaditya invaded Ujjain and drove away from the Śakas. To commemorate this event, he started a new era called the "Vikrama era"; the Ujjain calendar started around 58–56 BCE, the subsequent Shaka era calendar was started in 78 CE at Pratishthana. The association of the era beginning in 57 BCE with Vikramaditya is not found in any source before the 9th century CE; the earlier sources call this era by various names, including Kṛṭa, the era of the Malava tribe, or Samvat. The earliest known inscription that calls the era "Vikrama" is from 842 CE.
This inscription of Chauhana ruler Chandamahasena was found at Dholpur, is dated Vikrama Samvat 898, Vaishakha Shukla 2, Chanda. The earliest known inscription that associates this era with a king called Vikramaditya is dated 971 CE; the earliest literary work that connects the era to Vikramaditya is Subhashita-Ratna-Sandoha by the Jain author Amitagati. For this reason, multiple authors believe that the Vikram Samvat was not started by Vikramaditya, who might be a purely legendary king or the title adopted by a king who renamed the era after himself. V. A. Smith and D. R. Bhandarkar believed that Chandragupta II adopted the title Vikramaditya, changed the name of the era to "Vikrama Samvat". According to Rudolf Hoernlé, the king responsible for this change was Yashodharman: Hoernlé believed that he conquered Kashmir, is the same person as the "Harsha Vikramaditya" mentioned in Kalhana's Rajatarangini. Earlier, some scholars believed that the Vikrama Samavat corresponded to the Azes era of the Indo-Scythian king King Azes.
However, this was disputed by Robert Bracey following the discovery of an inscription of Vijayamitra, dated in two eras. The theory seems to be now discredited by Falk and Bennett, who place the inception of the Azes era in 47–46 BCE; the traditional New Year of Vikram Samvat is one of the many festivals of Nepal, marked by parties, family gatherings, the exchange of good wishes, participation in rituals to ensure good fortune in the coming year. It occurs in mid-April each year, coincides with the traditional new year in Assam, Burma, Kerala, Manipur, Punjab, Sri Lanka, Tamil Nadu and Thailand. In addition to Nepal, the Vikram Samvat calendar is recognized in North and East India, in Gujarat among Hindus. Hindu religious festivals are based on a Luni-Solar calendar, not Solar calendar, based on Vikram Samvat. In North India, the new year in Vikram Samvat starts from the first day of Chaitra Skukla paksha. In Buddhist communities, the month of Baishakh is associated with Buddha's Birthday, it commemorates the birth and passing of Gautama Buddha on the first full moon day in May, except in a leap year when the festival is held in June.
Although this festival is not held on the same day as Pahela Baishakh, the holidays fall in the same month of the Bengali and Theravada Buddhist calendars, are related through the spread of Hinduism and Buddhism in the Indian subcontinent. In Gujarat, the day after Diwali is celebrated as the first day of the Vikram Samvat calendar, the first day of the month Kartik; the Vikrami era is an ancient calendar and has been used by Hindus and Sikhs. It is one of the several regional Hindu calendars that have been in use on the Indian subcontinent, it is based on twelve synodical lunar months and 365 solar days; the lunar new year starts on the new moon in the month of Chaitra. This day, known as Chaitra Sukhladi, is a restricted holiday in India; the Vikrami Samvat has been in use in the Indian subcontinent since ancient times, remains in use by the Hindus in north, w
The Ethiopian calendar or Eritrean calendar is the principal calendar used in Ethiopia and serves as the liturgical year for Christians in Eritrea and Ethiopia belonging to the Eritrean Orthodox Tewahedo Church, Ethiopian Orthodox Tewahedo Church, Eastern Catholic Churches, the Coptic Orthodox Church of Alexandria, Ethiopian-Eritrean Evangelicalism. It is a solar calendar which in turn derives from the Egyptian calendar, but like the Julian calendar, it adds a leap day every four years without exception, begins the year on August 29 or August 30 in the Julian calendar. A gap of 7–8 years between the Ethiopian and Gregorian calendars results from an alternative calculation in determining the date of the Annunciation. Like the Coptic calendar, the Ethiopic calendar has 12 months of 30 days plus 5 or 6 epagomenal days, which comprise a thirteenth month; the Ethiopian months begin on the same days as those of the Coptic calendar, but their names are in Ge'ez. A 6th epagomenal day is added every 4 years, without exception, on August 29 of the Julian calendar, 6 months before the corresponding Julian leap day.
Thus the first day of the Ethiopian year, 1 Mäskäräm, for years between 1900 and 2099, is September 11. However, it falls on September 12 in years before the Gregorian leap year. Enkutatash is the word for the Ethiopian New Year in Amharic, the official language of Ethiopia, while it is called Ri'se Awde Amet in Ge'ez, the term preferred by the Ethiopian & Eritrean Orthodox Tewahedo Churchs, it occurs on September 11th in the Gregorian Calendar. The Ethiopian Calendar Year 1998 Amätä Məhrät began on the Gregorian Calendar Year on September 11th, 2005. However, the Ethiopian Years 1992 and 1996 began on the Gregorian Dates of'September 12th 1999' and'2003' respectively; this date correspondence applies for the Gregorian years 1900 to 2099. The Ethiopian leap year is every four without exception, while Gregorian centurial years are only leap years when divisible by 400; as the Gregorian year 2000 is a leap year, the current correspondence lasts two centuries instead. The start of the Ethiopian year falls on August 30th.
This date corresponds to the Old-Style Julian Calendar. This deviation between the Julian and the Gregorian Calendar will increase with the passing of the time. You can observe the real start date in the future centuries in a Gregorian to Ethiopian Date Converter. To indicate the year and followers of the Eritrean churches today use the Incarnation Era, which dates from the Annunciation or Incarnation of Jesus on March 25, AD 9, as calculated by Annianus of Alexandria c. 400. Meanwhile, Europeans adopted the calculations made by Dionysius Exiguus in AD 525 instead, which placed the Annunciation 8 years earlier than had Annianus; this causes the Ethiopian year number to be 8 years less than the Gregorian year number from January 1 until September 10 or 11 7 years less for the remainder of the Gregorian year. In the past, a number of other eras for numbering years were widely used in Ethiopia and the Kingdom of Aksum; the most important era – once used by the Eastern Christianity, still used by the Coptic Orthodox Church of Alexandria – was the Era of Martyrs known as the Diocletian Era, or the era of Diocletian and the Martyrs, whose first year began on August 29, 284.
Respective to the Gregorian and Julian New Year's Days, 31⁄2 to 4 months the difference between the Era of Martyrs and the Anni Domini is 285 years. This is because in AD 525, Dionysius Exiguus decided to add 15 Metonic cycles to the existing 13 Metonic cycles of the Diocletian Era to obtain an entire 532 year medieval Easter cycle, whose first cycle ended with the year Era of Martyrs 247 equal to year DXXXI, it is because 532 is the product of the Metonic cycle of 19 years and the solar cycle of 28 years. Around AD 400, an Alexandrine monk called Panodoros fixed the Alexandrian Era, the date of creation, on 29 August 5493 BC. After the 6th century AD, the era was used by Ethiopian chronologists; the twelfth 532 year-cycle of this era began on 29 August AD 360, so 4×19 years after the Era of Martyrs. Bishop Anianos preferred the Annunciation style as 25 March, thus he shifted the Panodoros era by about six months, to begin on 25 March 5492 BC. In the Ethiopian calendar this was equivalent to 15 Magabit 5501 B.
C.. The Anno Mundi era remained in usage until the late 19th century; the 4 year leap-year cycle is associated with the four Evangelists: the first year after an Ethiopian leap year is named the John-year, followed by the Matthew-year, the Mark-year. The year with the 6th epagomenal day is traditionally designated as the Luke-year. There are no exceptions to the 4 year leap-year cycle, like the Julian calendar but unlike the Gregorian calendar; these dates are valid only from March 1900 to February 2100. This is because 1900 and 2100 are not leap years in the Gregorian calendar, while they are still leap year
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
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
The Buddhist calendar is a set of lunisolar calendars used in mainland Southeast Asian countries of Cambodia, Laos and Thailand as well as in Sri Lanka and Chinese populations of Malaysia and Singapore for religious or official occasions. While the calendars share a common lineage, they have minor but important variations such as intercalation schedules, month names and numbering, use of cycles, etc. In Thailand, the name Buddhist Era is a year numbering system shared by the traditional Thai lunisolar calendar and by the Thai solar calendar; the Southeast Asian lunisolar calendars are based on an older version of the Hindu calendar, which uses the sidereal year as the solar year. One major difference is that the Southeast Asian systems, unlike their Indian cousins, do not use apparent reckoning to stay in sync with the sidereal year. Instead, they employ their versions of the Metonic cycle. However, since the Metonic cycle is not accurate for sidereal years, the Southeast Asian calendar is drifting out of sync with the sidereal one day every 100 years.
Yet no coordinated structural reforms of the lunisolar calendar have been undertaken. Today, the traditional Buddhist lunisolar calendar is used for Theravada Buddhist festivals, no longer has the official calendar status anywhere; the Thai Buddhist Era, a renumbered Gregorian calendar, is the official calendar in Thailand. The calculation methodology of the current versions of Southeast Asian Buddhist calendars is based on that of the Burmese calendar, in use in various Southeast Asian kingdoms down to the 19th century under the names of Chula Sakarat and Jolak Sakaraj; the Burmese calendar in turn was based on the "original" Surya Siddhanta system of ancient India. One key difference with Indian systems is that the Burmese system has followed a variation of the Metonic cycle, it is unclear from where, how the Metonic system was introduced. The Burmese system, indeed the Southeast Asian systems, thus use a "strange" combination of sidereal years from Indian calendar in combination with the Metonic cycle better for tropical years.
In all Theravada traditions, the calendar's epochal year 0 date was the day in which the Buddha attained parinibbāna. However, not all traditions agree on when it took place. In Burmese Buddhist tradition, it was 13 May 544 BCE, but in Thailand, it was 11 March 545 BCE, the date which the current Thai lunisolar and solar calendars use as the epochal date. Yet, the Thai calendars for some reason have fixed the difference between their Buddhist Era numbering and the Christian/Common Era numbering at 543, which points to an epochal year of 544 BCE, not 545 BCE. In Myanmar, the difference between BE and CE can be 543 or 544 for CE dates, 544 or 543 for BCE dates, depending on the month of the Buddhist Era. In Sri Lanka, the difference between BE and CE is 544; the calendar recognizes two types of months: sidereal month. The Synodic months are used to compose the years while the 27 lunar sidereal days, alongside the 12 signs of the zodiac, are used for astrological calculations; the days of the month are counted in two halves and waning.
The 15th of the waxing is the civil full moon day. The civil new moon day is the last day of the month; because of the inaccuracy of the calendrical calculation systems, the mean and real New Moons coincide. The mean New Moon precedes the real New Moon; as the Synodic lunar month is 29.5 days, the calendar uses alternating months of 29 and 30 days. Various regional versions of Chula Sakarat/Burmese calendar existed across various regions of mainland Southeast Asia. Unlike Burmese systems, Lan Na, Lan Xang and Sukhothai systems refer to the months by numbers, not by names; this means reading ancient texts and inscriptions in Thailand requires constant vigilance, not just in making sure one is operating for the correct region, but for variations within regions itself when incursions cause a variation in practice. However, Cambodian month system, which begins with Margasirsa as the first month, demonstrated by the names and numbers; the Buddhist calendar is a lunisolar calendar in which the months are based on lunar months and years are based on solar years.
One of its primary objectives is to synchronize the lunar part with the solar part. The lunar months twelve of them, consist alternately of 29 days and 30 days, such that a normal lunar year will contain 354 days, as opposed to the solar year of ~365.25 days. Therefore, some form of addition to the lunar year is necessary; the overall basis for it is provided by cycles of 57 years. Eleven extra days are inserted in every 57 years, seven extra months of 30 days are inserted in every 19 years; this provides 20819 complete days to both calendars. This 57-year cycle would provide a mean year of about 365.2456 days and a mean month of about 29.530496 days, if not corrected. As such, the calendar adds an intercalary month in leap years and sometimes an intercalary day in great leap years; the intercalary month not only corrects the length of the year but corrects the accumulating error of the month to extent of half a day. The average length of the month is further corrected by adding a day to Nayon