Moon Days, and Where They Actually Came From

We do not practise on the new moon or the full moon. Ask why and you will get the same answer everywhere, in almost the same words: the full moon is prāṇa, the end of the inhalation, light and upward and ungrounded; the new moon is apāna, the end of the exhalation, heavy and downward and disinclined to move.

It is a good answer. It is memorable, it maps onto something you can feel in your own breath, and it has been repeated so many times on so many studio websites that it now reads as doctrine.

I went looking for where Guruji said it.

He did not write it down

It is not in Yoga Mala, his only book. The one place that book takes up lunar timing is a passage on brahmacharya — when to have intercourse if you want children — and it says nothing about āsana.

It is not in Krishnamacharya's Yoga Makaranda either, the 1934 text this whole lineage descends from. Moon days are simply absent.

The wording everybody quotes — prāṇa at the top of the inhalation, apāna at the bottom of the exhalation — traces to a short essay published under Tim Miller's name and reproduced verbatim across dozens of studio sites. It carries no date. The earliest copy of it in the Internet Archive is from September 2014, which is a ceiling, not a date: it may be much older and simply never captured. No print publication is cited by any reproduction I could find.

So the canonical explanation for moon days is an undated web essay by an American teacher, restated until it became tradition.

What Jois himself is reported to have said is different

The rationale attributed to Jois in person is not about prāṇa and apāna at all. It is astrological: that when earth, sun and moon line up, a particular conjunction of nakṣatras — the lunar mansions of jyotiṣa — makes injury likelier and slower to heal.

That is at least in character. "Jois" is itself a South Indian rendering of jyotiṣa. Astrology was the family trade.

But this too reaches us only through students recounting what they heard. There is no text.

The best-documented origin is much more ordinary

In 2013 Eddie Stern — who co-edited Guruji and knew the household as well as any outsider — wrote a letter explaining moon days, and his account has nothing to do with energy.

Jois taught at the Maharaja's Sanskrit College in Mysore from 1937 to 1973. That college closed each month on amāvāsyā and pūrṇimā, and on the days either side. Not for yogic reasons. Its Brahmin teachers and students had ritual obligations on those tithis — pitṛ tarpaṇa, the offerings to the ancestors, which fall on the new moon, and ritual bathing after.

The college shut. So the yoga shāla shut. Jois kept the rhythm of his working life for thirty-six years and carried it forward into his own teaching, and the rest of us inherited a Sanskrit college's holiday calendar and went looking for a reason.

Stern relays two further things Jois said — that a teacher who introduces new material on a moon day will find his own knowledge declining, and the nakṣatra injury claim — and he is careful to mark both as traditional assertions he could not himself verify. That care is worth copying.

Nobody else does this

Moon days are not a feature of yoga. They are a feature of this lineage.

Krishnamacharya taught Jois and he taught Iyengar, and the Iyengar world does not observe moon days. Neither does the Sivananda line, nor Scaravelli's. Students of Krishnamacharya's broader circle practised straight through every phase, because it was never part of what he gave them. The practice descends through Pattabhi Jois specifically, and through the Mysore timetable he kept.

The moon in the texts is inside the body

There is a temptation, when the sourcing gets thin, to reach past Jois into the haṭha canon and say the old books were talking about this all along. They were not, and the reason matters.

The haṭha texts have an elaborate moon. It is at the palate. From it drips amṛta, the nectar, and a sun at the navel consumes it, and that consumption is why the body ages.

That is Haṭha Yoga Pradīpikā 3.77, and the verses after it teach viparīta karaṇī — turn the body over, and the sun is now above and the moon below, and the nectar is no longer consumed. Inversion as a way of not spending yourself.

This is a moon you carry. It has a location in the body, it is paired with a sun, and the practice is done to it rather than in response to it. Nowhere in that material is there an instruction to stop practising when the moon in the sky is full. Reading the calendrical observance back into these verses is a category error, and a common one.

Even haṭha itself will not settle down. Brahmānanda's Jyotsnā commentary glosses ha as sun and ṭha as moon; the Yogabīja reverses it; a third reading takes the word as plain force and no sun or moon at all. Two incompatible etymologies inside the tradition, on the tradition's own central word.

So should we practise?

Here is the honest position.

The reason you were given is not the reason. Nobody can source it to Guruji. The best-documented origin of moon days is a Brahmin college's ritual calendar, transmitted by one teacher who spent thirty-six years inside it. The physics of the moon's pull on your body rules out the mechanism people reach for — see the pull, where the number is a billion times smaller than a gram. And the one real lunar signal in human physiology is in sleep, not in tissue, and is smaller and stranger than the folklore.

None of that is an argument for practising on moon days.

A rest day twice a month, fixed in advance, that nobody has to justify and nobody can negotiate, is a good thing to have in a practice that otherwise runs six mornings a week and rewards not stopping. It arrives whether or not you are tired, which is the point — you do not get to decide you have earned it. It puts every student in a room on the same schedule, which is how a shāla stays a shāla instead of a gym. And it ties the practice to something that is not the practice: a body in the sky, visible from anywhere, on a rhythm nobody set.

Those are real reasons. They do not need prāṇa and apāna, and they survive finding out that the traditional explanation cannot be traced.

What I would not do is teach the folk reason as fact. Say the practice is a lineage observance — which is true, and sufficient — or say plainly that the stated reason is untraceable and the day is kept anyway. Both are honest. Repeating an undated web essay as though it came from Guruji is not.

And keep your shāla's list. The dates that close your room are the dates that close your room; the calculator here exists to show you why two rooms disagree, not to overrule either.

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