The Uposatha (Sanskrit: Upavasatha) is a Buddhist day of observance, in existence from the Buddha's time (600 BCE), and still being kept today in Buddhist countries. The Buddha taught that the Uposatha day is for "the cleansing of the defiled mind," resulting in inner calm and joy. On this day, both lay and ordained members of the sangha intensify their practice, deepen their knowledge and express communal commitment through millennia-old acts of lay-monastic reciprocity. On these days, the lay followers make a conscious effort to keep the Five Precepts or (as the tradition suggests) the eight precepts. It is a day for practicing the Buddha's teachings and meditation.
Depending on the culture and time period, uposatha days have been observed from two to six days each lunar month.
In general, Uposatha is observed about once a week in Theravada countries in accordance with the four lunar phases: the new moon, the full moon, and the two quarter moons in between. In some communities, such as in Sri Lanka, only the new moon and full moon are observed as uposatha days.
In Burmese Buddhism, Uposatha (called ဥပုသ်နေ့ubot nei) is observed by more pious Buddhists on the following days: waxing moon (လဆန်းla hsan), full moon (လပြည့်နေ့la pyei nei), waning moon (လဆုတ်la hsote), and new moon (လကွယ်နေ့la kwe nei). The most common days of observance are the full moon and the new moon. In precolonial Burma, Uposatha was a legal holiday that was observed primarily in urban areas, where secular activities like business transactions came to a halt. However, since colonial rule, Sunday has replaced Uposatha as the legal day of rest. All major Burmese Buddhist holidays occur on Uposathas, namely Thingyan, the beginning of Vassa (beginning in the full moon of Waso, around July, to the full moon of Thadingyut, around October). During this period, Uposatha is more commonly observed by Buddhists than during the rest of the year. During Uposatha days, Buddhist monks at each monastery assemble and recite the patimokkha, a concise compilation of the Vinaya.
In Mahayana countries that use the Chinese calendar, the Uposatha days are observed ten times a month, on the 1st, 8th, 14th, 15th, 18th, 23rd, 24th and final three days of each lunar month. Alternatively, one can only observe Uposatha days six times a month; on the 8th, 14th, 15th, 23rd and final two days of each lunar month. In Japan, these six days are known as the roku sainichi (六斎日, Six Days of Fasting).
Names of Full Moon Uposatha Days
The Pali names of the uposatha days are based on the Sanskrit names of the nakśatra (Pali: nakkhatta), the constellations or lunar mansions through which the moon passes within a lunar month.
In the Buddha's time, some ascetics used the new and full moon as opportunities to present their teachings. The Uposatha Day was instituted by the Buddha at the request of King Bimbisara, and the Buddha instructed the monks to give teachings to the laypeople on this day, and told the monks to recite the Patimokkha every second Uposatha day.
On each uposatha day, devout Upāsaka and Upāsikā practice the Eight Precepts, perhaps echoing the Buddha's teaching that laypeople should "imitate" arhats on Uposatha days. The first five of the eight precepts are similar to the five precepts, that is, to refrain from killing living beings, stealing, wrong speech and to abstain from intoxicating drink or drugs, but the third precept is abstinence of all sexual activity instead of refraining from sexual offenses. The eight precepts are similar to the ten precepts observed by novice monks, except that the seventh and eighth precepts for the novices are combined, the ninth novice precept becomes the eighth, and the tenth novice precept (non-acceptance of gold and silver, use of money) is excluded as being impracticable for a lay person. Thus, the final three precepts are to abstain from eating at the wrong time (after midday); to abstain from entertainment such as dancing, singing, music, watching shows, as well as to abstain from wearing garlands, perfumes, cosmetics, and personal adornments; and to abstain from luxurious seats and beds.
For lay practitioners who live near a Buddhist temple, the uposatha is an opportunity for them to visit it, make offerings, listen to sermons by monks and participate in meditation sessions. For lay practitioners unable to participate in the events of a local monastery, the uposatha is a time to intensify one's own meditation and Dhamma practice, for instance, meditating an extra session or for a longer time, reading or chanting special Buddhist texts,recollecting or giving in some special way.
Presently, the uposatha vows are mostly associated with Theravāda Buddhism in South and Southeast Asia, but it was a widespread practice in China as well, and is still practiced.
The eight precepts are meant to give lay people an impression of what it means to live as a monastic, and the precepts "may function as the thin end of a wedge for attracting some to monastic life." The objective of the eight precepts is different from the five in that they are less moral in nature, but more focused on developing meditative concentration, and preventing distractions. Among the eight precepts, the third precept is about maintaining chastity. Buddhist tradition therefore requires lay people to be chaste on observance days, which is similar to the historical Indian tradition of being chaste on parvan days. As for the sixth rule, this means not having food after midday, in imitation of a nearly identical rule for monks. Fluids are allowed. Taiwanese physician Ming-Jun Hung and his co-authors have analyzed early and medieval Chinese Buddhist Texts and argue that the main purposes of the half-day fast is to lessen desire, improve fitness and strength, and decrease sleepiness. Historically, Chinese Buddhists have interpreted the eight precepts as including vegetarianism.
The seventh precept is sometimes also interpreted to mean not wearing colorful clothes, which has led to a tradition for people to wear plain white when observing the eight precepts. This does not necessarily mean, however, that a Buddhist devotee dressed in white is observing the eight precepts all the time. As for the eighth precept, not sitting or sleeping on luxurious seats or beds, this usually comes down to sleeping on a mat on the floor. Though not specified in the precepts themselves, in Thailand and China, people observing the precepts usually stay in the temple overnight. This is to prevent temptations at home which break the eight precepts, and helps foster the community effort in upholding the precepts.
On the new-moon and full-moon uposatha, in monasteries where there are four or more bhikkhus, the local Sangha will recite the Patimokkha. Before the recitation starts, the monks will confess any violations of the disciplinary rules to another monk or to the Sangha. Depending on the speed of the Patimokkha chanter (one of the monks), the recitation may take from 30 minutes to over an hour. Depending on the monastery, lay people may or may not be allowed to attend.
Describing his experience of Uposatha day in Thailand, Khantipalo (1982a) writes:
Early in the morning lay people give almsfood to the bhikkhus who may be walking on almsround, invited to a layman's house, or the lay people may take the food to the monastery. Usually lay people do not eat before serving their food to the bhikkhus and they may eat only once that day.... Before the meal the laity request the Eight Precepts [from the bhikkhus] ..., which they promise to undertake for a day and night. It is usual for lay people to go to the local monastery and to spend all day and night there.... [In monasteries where] there is more study, [lay people] will hear as many as three or four discourses on Dhamma delivered by senior bhikkhus and they will have books to read and perhaps classes on Abhidhamma to attend.... In a meditation monastery ..., most of their time will be spent mindfully employed – walking and seated meditation with some time given to helping the bhikkhus with their daily duties. So the whole of this day and night (and enthusiastic lay people restrict their sleep) is given over to Dhamma.
Special Uposatha days
In Thailand five full-moon Uposatha days are of special significance and are called puja:
Visakha Puja or Visakha Uposatha  or Vesak ("Buddha Day"):
is the most sacred Buddhist holiday. It is the anniversary of the Buddha's birth, awakening and parinibbana.
Poson Poya corresponds to the Jeṭṭhā uposatha, which falls in June. It is of special significance in Sri Lanka because the monk Mahinda, Asoka's son, officially introduced Buddhism to Sri Lanka on this day in the 3rd century B.C.
Esala Poya corresponds to Āsāḷhā uposatha, the full moon of July, and is described above. This day has special significance in Sri Lanka because it was the day that 56 nobles, headed by Prince Ariṭṭha, became the first Sri Lankans to be fully ordained as a bhikkhus at Cetiyagiri in Mihintale by Mahinda and his companions. It therefore marks the founding of the Lankan Bhikkhu Sangha.
In Tibet and Bhutan, there are four full moon Uposatha days that are of importance
^For a description of the contemporary practice of the Uposatha in Thailand, see Khantipalo (1982a), which is also excerpted in this article below.
Kariyawasam (1995), ch. 3, also underlines the continuity of the ancient uposatha practice in Sri Lanka: "The poya [Sinhala for uposatha] observance, which is as old as Buddhism itself, has been followed by the Sinhala Buddhists up to the present day, even after the Christian calendar came to be used for secular matters. Owing to its significance in the religious life of the local Buddhists, all the full-moon days have been declared public holidays by the government."
^The uposatha day is sometimes likened to the Judeo-Christian notion of the Sabbath. Pali English dictionaries that define "Uposatha" as "Sabbath," are Buddhadatta (2002), p. 63, and PED(Rhys-Davids & Stede,1921-25), p. 151.
For an example of the Uposatha being equated with Sabbath by a modern Buddhist master, see Mahasi (undated), p. 2, where he writes: "For lay people, these rules [of discipline] comprise the eight precepts which Buddhist devotees observe on the Sabbath days (uposatha) and during periods of meditation." Harvey (1990), p. 192, also refers to the uposatha as "sabbath-like."
^, with the full moon being the most important one, followed by the new moon. Each lunar month has eight days after both the new moon and full moon Uposatha days and then either six or seven days after the other two quarter moon Uposatha days. Thus, in relation to the Gregorian calendar's seven-day week, sometimes there are two uposatha days in a week (such as occurred the week of August 17, 2006, when uposatha days fell on August 17 and August 23, 2006) and sometimes there are none (such as occurred the week of January 15, 2006, which fell between uposatha days on January 14 and January 22, 2006). Nonetheless, there are four uposatha days a month and the average solar month's week has one uposatha day.
^More specifically, using a Buddhist calendar, Uposatha is observed on the following four days of the lunar month (PTS, 1921-25, pp. 151-2):
first (new moon)
eighth (first quarter or waxing moon)
fifteenth (full moon)
twenty-third (last quarter or waning moon)
According to the Pali English Dictionary (Rhys Davids and Stede, 1921-25, pp. 16, 152), the lunar month's eighth day (that is, the eighth day after the new moon) and twenty-third day (which is the eighth day after the full moon) are called in Pali atthama, which literally means the "eighth," that is, the eighth day of the lunar half-month.
^Nyanaponika & Bodhi (1999), pp. 24, 307 n. 26. Nyanaponika & Bodhi refers to the quarter-moon days as "semi-Uposatha." Harvey (1990), p. 192, states that the uposatha is observed "at the full-moon, new-moon and, less importantly, two half-moon days." He goes on to state: "Except at times of major festivals, observance [uposatha] days are attended only by the more devout, who spend a day and night at their local monastery." Kariyawasam (1995), ch. 3, makes a similar observation in regards to modern Sinhalese society: "The popular practice is to observe [the Eight Precepts] on full-moon days, and, among a few devout lay Buddhists, on the other phases of the moon as well."
^ abMelford, Spiro (1970). Buddhism and Society: A Great Tradition and its Burmese Viscittudes. Harper and Row. pp. 214–228.
^See, for instance, the "Muluposatha Sutta" (AN 3.70) (Thanissaro, 1997b) regarding Uposatha-specific recollections and Thanissaro (1999) for the general Buddhist practice of recollections. In the Muluposatha Sutta, the Buddha recommends practicing recollection of the Three Jewels as well as of one's own virtue (sila) and of the wholesome qualities that leads to rebirth as a deva. In this sutta, if one spends the Uposatha engaged in such a recollection, then that Uposatha acquires the name of the recollection, such as Dhamma-Uposatha or virtue-Uposatha.
^See, for instance, Buddhadatta (2002), p. 63, and Bullitt (2005).
^Bullitt (2005). Bullitt orders these special uposatha days in accordance with the Gregorian calendar, where Magha Uposatha thus starts the calendar year. However, in accordance with Asian lunar calendars, where the new year starts in mid April, Visakha Uposatha is the first special uposatha day of the year. The lunar calendar ordering of these days is maintained in this article for primarily two reasons: Visakha Uposatha is the most important of the uposatha festivals; and, ordering these uposatha days in this manner (i.e., Visakha Uposatha [Buddha Day], Asalha Uposatha [Dhamma Day], Magha Uposatha [Sangha Day]) celebrates the Triple Gem (Buddha, Dhamma, Sangha) in the order in which it is traditionally enumerated. Also see Kariyawasam, ch. 3, "Poya Days," where he identifies the relevance of all twelve full-moon uposatha days in contemporary Sinhala culture.
^"Vesākha" (Pali) is the second month of the Buddhist lunar year, usually occurring in the Gregorian calendar's February. In Thailand this day is called 'Visakha Puja.' The word puja means "veneration" or "offering" and in Thailand is suffixed to all Uposatha days. (Pali month names are from the Pali English Dictionary (Rhys Davids & Stede,1921-25, p. 531 s.v. "māsa").
^For Mahayana Buddhists, the celebration of the Buddha's birthday is independent of recognitions of his awakening and parinibbana and is celebrated on the waxing moon of the fourth Chinese lunar month.
^"Āsālha" (Pali) is the fourth lunar month, usually around July.
^Pavarana Day is in the seventh lunar month of Assayuja (Pali), usually in October.
^Anapanasati Day is the eighth lunar month of Kattika (Pali), usually in November.
^The Anapanasati Sutta ("Mindfulness of Breathing Discourse," MN 118) (Thanissaro, 2006) opens on Pavarana Day in the town of Savatthi where the Buddha declares to an assembly of monks that he is so happy with the assembly's practice that he would stay in Savatthi another month. After that month passes, the Buddha delivers the core instructions of the Anapanasati Sutta, instructions which have guided lay people and monastics to higher achievement for millennia. Thus, given this canonical chronology, Anapanasati Day is celebrated a lunar month after Pavarana Day.
^"Māgha" (Pali) is the eleventh lunar month, usually around February.
^The three-line Ovada-Patimokkha Gatha (Pali: "Patimokkha Exhortation Verse") (translated in Dhammayut Order in the United States of America, 1994) includes the Buddha's famous dictum: "Not doing any evil, doing what is skillful, purifying one's own mind, this is the Buddha's teaching." This verse is familiar to many Westerners because it is rehashed in the widely popular Dhammapada, chapter XIV, verses 183-85 (Thanissaro, 1997a).
Hung, Ming-jung; Kuo, Cheng-deng; Chen, Gau-yang (July 2002), 佛教的「過午不食」 [No-food-after-midday precept [sic] (Vikala Bhojana Veramani) in Buddhism], Buddhism and Science, 3 (2): 51–64, ISSN1607-2952, archived from the original on 4 December 2018
Kariyawasam, A.G.S. (1995). Buddhist Ceremonies and Rituals of Sri Lanka (The Wheel Publication No. 402/404). Kandy, Sri Lanka: Buddhist Publication Society. Retrieved 2007-10-22 from "Access to Insight" (1996 transcription) at [www.accesstoinsight.org].
Khantipalo, Bhikkhu (1982a). Lay Buddhist Practice: The Shrine Room, Uposatha Day, Rains Residence (The Wheel No. 206/207). Kandy, Sri Lanka:Buddhist Publication Society. Also transcribed (1995) and available on-line at [www.accesstoinsight.org].
Khantipalo, Bhikkhu (trans.) (1982b). Visakhuposatha Sutta: The Discourse to Visakha on the Uposatha with the Eight Practices [AN 8.43]. Available on-line at [www.accesstoinsight.org].
Ñanavara Thera (Somdet Phra Buddhaghosacariya) & Bhikkhu Kantasilo (trans.) (1993). Uposatha Sila: The Eight-Precept Observance. Thailand:The Office of the Secretary of the Supreme Patriarch. Available on-line at [www.accesstoinsight.org].
Piyadassi Thera (trans.) (1999b). Ratana Sutta: The Jewel Discourse [Sn 2.1]. Available on-line at [www.accesstoinsight.org].
Rhys Davids,T.W. & Hermann Oldenberg (trans.) (). Vinaya Texts (Part I). Oxford:Clarendon Press. Available on-line at [www.sacred-texts.com]. The chapter on the Uposatha, "Second Khandhaka (The Uposatha Ceremony, and the Pâtimokkha)," is available at [www.sacred-texts.com]. The chapter on Pavarana Day, "Fourth Khandhaka (The Parâvanâ Ceremony)," is available at [www.sacred-texts.com].