Days of Uposatha according to the Suttas

This is probably a Vinaya question, so I’d be glad if @Brahmali would be kind enough to respond, or anyone else of course who knows…

In the suttas the Uposatha is mentioned in several contexts - gathering, mythological, sila-practice. And there are three days given on which it can take place: ‘the 8th day’, ‘the 14th day’ and ‘the 15th day’ of the fortnight. Theoretically this should mean ‘the half-moon’, ‘the full and new moon’, and the day just before.

Yet when a specific moon-phase is mentioned in connection with the uposatha it’s always the full-moon (SN 22.85, MN 109, MN 110, MN 118, DN 2, DN 18, DN 19, Snp 3.12). Nowhere have I found an uposatha (or a Buddha discourse) that would take place at a ‘new moon’.

We only infer the ‘new moon uposatha’ from the ‘15th’ which should mean both 15ths, i.e. the full and new moon.

Now my question, is it possible that originally the uposatha only took place on full moons and was expanded only later to new, and then to half-moons?

Where in the Vinaya is the new moon explicitly stated (apart from ‘the 15th’)?

Of the three dates the most auspicious was (in later suttas) certainly the 15th (see e.g how the ‘treasures’ appear to the wheel-turning monarch on a 15th uposatha only (in SN 22.96, MN 129, DN 17) or how the ‘Four Great Kings’ watch over the 15th, and only their sons and ministers over the 8th and 14th.


Early Buddhist Monachism by Sukumar Dutt(quote have some typos):

But this Uposatha ceremony was by no )^eans a Buddhist
innoTation, for its germs may be traced in a well-known
Vedio institution, which strikingly exemplifies the dictum
of Edward Clodd, stated as it is in an extreme form, that
*‘in religions there are no inventions, only survivals
The rudimentary idea in the Buddhist Uposatha service
seems to be the observance of sacred days. Bound about
this, certain peculiarly Buddhistic ideas have gathered
together, e.g. the Buddhist doctrine of confession. But
the rite itself, which is, as I shall show, a curious combina-
tion of certain distinct ideas, has passed through two
principal stages. At first it was of a practical character,
being one of the main regulations of monastic life, perhaps
the chief instrument of communal self-government in the
Buddhist Sangha. But this practical character and pur-
pose of the Uposatha service afterwards evaporated. -It
became a mere ceremonial observance, serving the same
purpose among the Buddhist Bhikkhus as the Holy Com-
munion amongst the 6bxistians, being nothing but the
formal embodiment of the corporate life of a cenobitxcal
society resident at an A v a s a .
The observance of the sacred days is found in the Vedio
times in close and inseparable connexion with certain
Vedio sacrifices.
The days of the Full Moon and the New Moon were from
the earliest times in India regarded as sacred for sacrificial
purposes. The Full Moon and the New Moon are effusively
greeted in two hymns of the Atharm-veda.^ The Vedio
^ See The Story of ihe Primitive Man, p. 185. * A.V., vii, n, 80.

I don’t think so, for if it had been the case that the recital of the Pātimokkha was originally held only on the full moon days, then it would have been described as a “monthly” event. As it is, the recital is in several places in the Vinaya described as occurring “fortnightly”, anvaddhamāsaṃ or anvaḍḍhamāsaṃ.


Thanks, I know the Dutt-passage, and while I share his line of thought I was looking for more source material in the Vinaya. The suttas just mention the full-moon.

Yes, I can see that. Does it also seem to you that the 8th and the 14th were secondary? Kd 2.3.3 says:

And thus, monks, should it be recited: The Order should be informed by an experienced, competent monk, saying: ‘Honoured sirs, let the Order listen to me. Today, the fifteenth, is an uposatha.

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It’s customary to speak of the “major uposatha” and “minor uposatha”. On the major uposatha the more devout laity keep the eight precepts and the monks hold a Pātimokkha recital. On the minor uposatha the laity keep the eight precepts but the monks don’t do anything special (or at least are not required by Vinaya to do anything special; what local custom may require of them is another story).

Since what is called the “minor uposatha” is the one that falls on the 8th days, I would concur in your calling this “secondary”. But it wouldn’t be correct to call the 14th secondary. Rather, the calendar is such that the major uposatha will sometimes (in fact most often) fall on the 15th day, but occasionally will fall on the 14th. But falling on the 14th day doesn’t make it any less of a “major uposatha” than when it falls on the 15th.


I should add that I’m not sure if the terms “major uposatha” and “minor uposatha” are a translation of any Pali expression. But even if they aren’t, they do reflect what is stated regarding these days in the Vinaya and the various Uposatha suttas in the AN.


Just to add a little to Venerable Dhammanando’s reply, here are some extracts from the Uposathakkhandaka, the section of the Vinaya that regulates these matters:

At one time the Master was staying at Rājagaha on Mount Vulture Peak. At that time, on the fourteenth, the fifteenth, and the eighth day of the half-month, the wanderers of other sects assembled and gave teachings. People went to listen to those teachings, and they acquired affection for and confidence in those wanderers. And the wanderers gained a following.

The Buddha then lays down the following rule:

“Monks, you should assemble on the fourteenth, the fifteenth, and the eighth day of the half-month.”

When the monks knew what the Master had said, they started assembling on those days. People came to hear a teaching, but the monks sat in silence. Those people complained and criticized them, “How can the Sakyan ascetics assemble on the fourteenth, the fifteenth, and the eighth day of the half-month, but then sit in silence like dumb pigs? Shouldn’t they give a teaching when they assemble?” The monks heard the complaints of those people and they told the Master. Soon afterwards the Master gave a teaching and addressed the monks:

“Monks, when you assemble on the fourteenth, the fifteenth, and the eighth day of the half-month, you should give a teaching.”

While the Master was in seclusion, he thought, “Let me allow the monks to recite a monastic code, consisting of those training rules that I have laid down for them. And that will be their procedure for the observance day.” Then, in the evening, when the Master had come out from seclusion, he gave a teaching and addressed the monks. He told them what he had thought, adding:

“Monks, you should recite the monastic code.”

Later on the Buddha regulated the frequency of the recitation:

Soon afterwards, knowing that the Master had allowed the recitation of the monastic code on the observance day, some monks recited it three times per half-month: on the fourteenth, on the fifteenth, and on the eighth day. They told the Master and he said:

Monks, you should not recite the monastic code three times per half-month. If you do, you commit an offense of wrong conduct. You should recite the monastic code once every half-month: on the fourteenth day or on the fifteenth day.

We will never know, of course, the degree to which this is true to what actually happened. Still, I think it is likely to reflect the situation in ancient Indian society fairly closely. There would be no point in making up an origin story without credibility, since its authority would be much reduced.


I’d be interested in a few other points regarding the uposatha, also from @Dhammanando if you’d be so kind…

The uposatha seems to be the clearest for lay people. They are invited to keep the eight silas, maybe meditate and listen to dhamma.

But for monastics, how is - according to the texts - the uposatha observed other than the recitation of the Patimokkha on full/new moon? What is for example to be done on ‘the eighth’ - i.e. half-moon according to the Vinaya? Just more meditation than usual?

Also I wonder about parisuddhi and purity. Is parisuddhi some sort of a declaration in which the sangha-meeting culminates?

Regarding purity I seem to get two messages from the texts: 1. uposatha/recitation is a context during which purification takes place, mostly through sangha-public confessionals. had to enter the uposatha already purified.

For the latter I especially think of AN 8.20 (also in the Vinaya) where the Buddha refuses to recite the Patimokkha because one participant is impure (and never recites it anymore henceforth). But if the purification through confession is supposed to take place during and after the recitation, why would the Buddha refuse to start? As I understand it there must have been a rule to come to the sangha meeting already purified, especially during the Buddha’s lifetime?

There is no obligation for monastics to do anything in particular on the 8th day. If the rule quoted above is taken as a command, then the monks should assemble and give a teaching. And this is exactly what you see in many parts of the Buddhist world. At Bodhinyana Monastery, however, we give most of our teachings on the weekends to make them more accessible to working people.

Although the full moon nights are often described as auspicious in the suttas, there is no obligation to do more meditation on these days. It is a custom, however, in some monasteries, especially in the Ajahn Chah tradition, to sit meditation all night on the uposatha days.

To take part in the pātimokkha recitation you have to be pure, which in practice means you have to have confessed any offences before the recitation starts. This is parisuddhi, purity. Those who are not able to take part in the pātimokkha recitation have to send their purity, parisuddhi, before the recitation can begin. If there are not enough monks or nuns in a particular monastery to recite the pātimokkha - the minimum number being four - the monastics must confess their offences and then declare their purity, parisuddhi. If there is only one monastic in a “monastery”, you don’t even need to declare your purity, merely the determining of the day as your uposatha.

The second one is the correct one. This is from the preamble to the pātimokkha:

What is the preliminary duty of the Order? The Venerables should declare purity, and I will recite the monastic code.

Indeed, there is such a rule. This is from the Vinaya section on suspending someone from the pātimokkha recitation:

A monk who has an unconfessed offense should not listen to the pātimokkha recitation. If he does, he commits an offense of wrong conduct.

And from the Vinaya section on the uposatha:

Anyone who has committed an offense should reveal it. If you havenʼt committed an offense, you should remain silent. If you are silent, I will regard you as pure. Just as one who is asked individually responds, so too, the announcement is made up to three times in this kind of assembly. If a monk remembers an offense but doesnʼt reveal it when an announcement is made up to the third time, he is lying in full awareness. And lying in full awareness is called an obstacle by the Master. A monk who remembers an offense and who is seeking purification should therefore reveal it. When itʼs revealed, he will be at ease.

Usually you confess your offenses before the recitation, ideally immediately after you have committed the offense, but at the latest you can do so during the recitation itself, that is, if your memory gets jogged by hearing the rules. You then just tell the person sitting next to you.


Thanks so much for the clarification!

It’s interesting to see the differences between suttas and Vinaya in that respect. Or rather the suttas don’t mention much except that the Patimokkha was recited.

An interesting sutta is AN 7.52 where the Buddha gives a dhamma talk specifically to lay people on uposatha. It could be a non-Patimokkha uposatha, or from before the rule that it should not be recited in front of laypeople, or they were somehow separate. But as far as I can tell it’s the only incidence where lay people get a teaching from the Buddha on any uposatha.

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@Brahmali: is this correct? -

8 - Dh
14 - Pat (or 15th) Dh
15 - Pat + Dh

Pat=Patimokkha; Dh=Dhamma sermon

It’s interesting that the it happens around the middle of the month. I wondered about the significance of the moon, here, and whether this significance still holds to be true? :slightly_smiling_face:

with metta

I don’t know about the current customs but some texts are ambivalent about the 14&15. It seems that sometimes it was the 14th and 15th. E.g. the ‘origin story’ in the vinaya says that wanderers meet three times a fortnight, on 8, 14 and 15. (see MN 146, Kd 2.4.2)


Well, remember these are lunar months, not months based on the solar calendar. So the idea is that the 14th or 15th will always be on either the new moon or the full moon. But thanks for making this point. We should probably use “lunar month” rather than just “month” in our translations. Otherwise many people are likely to miss it.


Gabriel: I don’t know about the current customs but some texts are ambivalent about the 14&15. It seems that sometimes it was the 14th and 15th. E.g. the ‘origin story’ in the vinaya says that wanderers meet three times a fortnight, on 8, 14 and 15. (see MN 146, Kd 2.4.2)

@Gabriel, yes the uposatha was both 14th and 15th, but the patimokkha recitation was either 14th or 15th, as presumably they would have kept their patimokkha for the 24hours between 14th and the 15th!

@Brahmali, oh that’s intriguing. I am unable to get my head around lunar calendars, currently. I will take your word for it. :grinning:

with metta,


To give you a sense of the lunar month, please refer to this nice website

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