The first and the fifteenth: why the whole city eats vegan twice a month

There are two days a month when the whole city changes how it eats. Every vegan place is full from early morning, there are queues at the banh mi shops, the markets sell briskly in tofu, and even the plain rice stalls put out a few meat-free trays.

Those are the first and the fifteenth of the lunar month. It is so familiar that few people ask why.

Where it comes from: periodic vegan days

In the Mahayana Buddhist tradition — the branch common in Vietnam, China, Japan and Korea — there is the practice of periodic vegan days: eating vegan not year-round but on particular days of the lunar month.

The two most common levels:

• Two days — the first and the fifteenth.
• Ten days — the 1st, 8th, 14th, 15th, 18th, 23rd, 24th, 28th, 29th and 30th.

There are also four-day and six-day observances — several levels so that people can choose according to what they can sustain. That is a notable feature of the practice: it has grades rather than one single standard.

Why the first and the fifteenth? They are the two clearest points of the lunar cycle — no moon at the start of the month, full moon in the middle. The lunar calendar follows the moon, so those two days are the easiest to remember without consulting anything.

Why it spread beyond the religious

This is the more interesting part. In Saigon today, far more people eat vegan on those two days than actually follow the Buddhist observance. Several reasons stack up:

• They are easy to remember. Nobody has to remind you and no app is needed. Look at the calendar and you know.
• The infrastructure is already there. On those days vegan places are open, markets stock vegan ingredients, and colleagues are eating vegan too, so nothing needs explaining. Eating vegan on any other day is much harder.
• It is light. Two days a month is within almost anybody's reach, with no change of lifestyle required.
• It comes with a reason you can state. “It's the first today” is a complete sentence; nobody asks further.

In other words, these two days function as a common meeting point. For anybody who wants to eat vegan but is reluctant to do it alone, this is the easiest place to start.

What happens on the trade side

For a food business these two days are unlike the rest of the month:

• Trade rises sharply, concentrated in two windows: early morning before work, and midday.
• Non-specialist places put out vegan dishes. A rice stall adds a few trays, a noodle shop makes a vegan broth.
• Markets raise the price of tofu and vegetables. Demand spikes for a day, prices tick up, and settle again the next.
• Kitchens have to prepare ahead. This is why large vegan orders on those days need one to two days' notice rather than the few hours that suffice otherwise.

How to eat out on those days without queuing

Three practical windows:

• 7:00–8:30 and 11:30–13:00 are the busiest. Office workers and people returning from the temple arrive together.
• After 14:00 or after 21:00 it empties out.
• From 22:00 to 5:00 there is essentially no wait — and at a 24-hour place, it is still the same day and still the same vegan meal.

The tidiest option if you are busy: order the evening before with a delivery time. In the morning you simply take delivery.

Is there a difference between the two days?

Not in terms of eating. Both are vegan days equally. The difference is in the ritual side and in how busy it gets: the fifteenth of the first, seventh and eighth lunar months are considerably busier than other months, coinciding with major festivals.

The seventh-month full moon is the busiest day of the year for vegan food businesses.

At the shops

Banh Mi XANH is open 24 hours, so on those days there is no closed window at all — including three in the morning. The five shops: 38 Lê Thị Riêng, 15B Nguyễn Thị Minh Khai, 2B Trần Hưng Đạo and 148B Đề Thám in District 1, and 210 Bùi Văn Ba in District 7.

To order ahead for a full-moon day, call 0923.183.183 and state the time you need it. Large orders should be placed one to two days ahead. Orders from 500,000d within 5km are delivered free.

Quick questions

Why the first and the fifteenth specifically?

They are the two clearest points of the lunar cycle — no moon at the start, full moon in the middle. The lunar calendar follows the moon, so they are the easiest days to remember without checking anything.

How many levels of observance are there?

Several, so people can choose what they can sustain: two days, four, six, or ten. The practice having grades rather than one standard is one of its notable features.

Can someone not Buddhist keep those days?

Yes, and a great many do. Those days are easy to remember, the food is available, and colleagues are eating vegan too — they work as a common starting point.

When should I eat out to avoid queues?

After 14:00 or after 21:00. The two busiest windows are 7:00–8:30 and 11:30–13:00, when office workers and temple-goers arrive at once.

How far ahead for a large order on a full-moon day?

One to two days rather than the few hours that suffice otherwise. Those are the days kitchens are already booked because demand spikes.

Which full moon is busiest?

The seventh lunar month. The first and eighth months are also considerably busier than others, coinciding with major festivals.