What Is a Zansho-mimai?

Mid-August. Obon has ended, the streets have gone a little quiet, and yet the sun is still fierce and the evening air still warm.

On the Japanese calendar, though, this stretch of the year is already autumn. Hot, and autumn. And for those few misaligned weeks — only then — Japan has a letter it sends.

It is called zansho-mimai, the lingering-heat greeting.

What you write in it is more or less fixed. “Still hot, isn’t it.” “Are you well?” That is the whole letter.

Here is what zansho-mimai is, traced gently for those meeting it for the first time.

A zansho-mimai is a short seasonal greeting sent at the end of summer to ask after someone’s health. It usually travels as a single postcard, and it carries no business of any kind.

The important word is mimai. The Japanese verb mimau originally meant to go and see how someone is — to call on them and ask whether they are all right. It is the same word used for visiting someone who is ill.

So a zansho-mimai was, at root, going to a person in the heat to see whether they had come through it. The letter is what happens when you cannot go. That is the order of things.

Which means the contents can be nothing more than the asking. There is no need to fill it with your own news — and holding back is, if anything, the better form.

Japan has one more letter of almost exactly this shape: the shochu-mimai, the midsummer greeting. The two are the same in substance and purpose. The only difference is when they arrive. On one particular day, the names trade places.

Why the name changes partway through August

The dividing line is a day called Risshu.

Japan still keeps, as a seasonal reference, an old division of the year into twenty-four parts — the nijūshi-sekki, or twenty-four solar terms. Risshu is one of them: the day autumn begins on the calendar.

Its date shifts slightly from year to year. In the almanac published by the National Astronomical Observatory of Japan, Risshu in 2026 falls on August 7th.

And the heat that lingers past that day has its own name: zansho, the remaining heat.

Arriving before Risshu — shochu-mimai
Arriving on or after Risshu — zansho-mimai

What counts is the day it reaches the other person. Around August 7th, the same letter simply changes its name.

The charming part is that this switch has nothing whatsoever to do with the temperature. The second half of August in Japan is, as a rule, still high summer. But the calendar says autumn, so the letter obeys the calendar. That is why the phrase “autumn has begun on the calendar, and yet…” is a fixed opening in Japanese correspondence.

The fact of the heat, and the formality of the season. Japan took that gap and gave it a letter of its own.

By when should it arrive?

The most commonly cited deadline is the end of August.

A greeting about “lingering heat” that lands in September reads as slightly late for the season, so most guidance sets August 31st as the edge.

Two finer markers are often mentioned as well, both of them solar terms:

Shosho — the term meaning “the heat subsides.” August 23rd in 2026. Ideally your card arrives by then
Hakuro — the term where autumn begins to deepen. September 7th in 2026. Even if you are running late, get it there before this one

In honesty, there is no single agreed answer about the closing date. Some explanations set no deadline at all; others say the end of August at the latest. The opening is precise; the ending is loose.

It is a seasonal greeting — so, before the season turns is about right.

Where the custom came from

The habit is said to have begun in the Edo period (1603–1868). What follows, though, is carried more by traditional accounts than by firm records, so please read it in that spirit.

Originally, it is explained, people returning to their family homes for Obon brought offerings for the spirits of their ancestors. Over time this widened beyond ancestors, into a habit of bringing a summer gift to anyone one was indebted to.

And for those too far away to visit, the goods and a written note were entrusted to a hikyaku — an Edo-period courier who carried letters and parcels on foot. This is the moment the form is born: I cannot come, so here is a letter instead.

The great change came in the Meiji era. Once postcards became available through the postal system established in 1873, the exchange of gifts gradually simplified into the sending of a greeting alone. By the Taishō era (1912–1926), it is said, the shochu-mimai and zansho-mimai had settled into the shape they hold today.

Visiting, then sending goods, then sending a letter, then a single postcard. The custom has grown lighter at every step. But the feeling it started from — are they all right? — stayed behind, lodged in that word mimai.

The summer postcard that disappeared

Japan once had a postcard made specifically for this season, called kamome-ru.

Issued from 1950 as the summer correspondence card, it gained a lottery number in 1986 — like the New Year’s cards, a matching number won you a prize. For decades these cards moved back and forth across the country every summer.

The peak came in 1993, when 340 million of them were printed. That is more than two per person in the country.

After that the numbers fell, year on year. Email and messaging apps became ordinary, and fewer and fewer people bought postcards. With the 2020 issue, kamome-ru was discontinued.

Illustrated summer postcards are still sold, and an ordinary postcard works perfectly well. But the shared national marker — this is the card you send in summer — is gone.

This is a custom in retreat, and it seems worth saying so plainly. And yet, for that very reason, a card that does arrive now carries more than it used to.

How to write one — four blocks

The form is clearly set, and once you know it the whole thing takes a few minutes. The usual order is:

The greeting itself — Zansho o-mimai mōshiagemasu (“I offer you my greetings in the lingering heat”). Written slightly larger than the body, and with no full stop
Weather and well-being — a line about this summer’s heat, and a word of concern for the reader’s health
The body — brief thanks, or a short note of your own news. Keeping it short is the skill
The date — never a specific day. Just the month or a season word: “August,” “late summer,” “Risshu”

One more rule saves a lot of hesitation: do not write “haikei” or “keigu.”

Japanese letters normally open and close with a matched pair of set phrases — begin with haikei, end with keigu. In a zansho-mimai, the opening line already performs that duty, so the pair is not added on top of it.

A short example:

My greetings to you in the lingering heat

Risshu has passed, and still the heat holds. I hope this finds you and yours as well as ever.

All is unchanged and well on my side. The heat looks set to stay a while yet — please take good care of yourself.

Late summer, 2026

That is enough. Having no business to raise is the business of this letter.

Worth knowing

A few points where people commonly hesitate.

You may send one during mourning. In Japan, a household that has lost a family member refrains for a period from celebratory greetings such as New Year’s cards; this period is called mochū. But a zansho-mimai is a seasonal greeting, not a celebration, so it is considered fine to send whether you are in mourning or the recipient is.

As a courtesy, though, people generally wait until the forty-nine days of mourning have passed, and when writing to someone in mourning they choose a quiet design rather than a bright, festive one.

It works as a late reply. If you received a shochu-mimai and let the reply slip, simply send it back as a zansho-mimai once Risshu has passed. There is, in effect, a name waiting for you when you are late.

When the other person is struggling, skip the weather. If they are unwell or have been through a disaster, write about them before you write about the heat. Asking after someone is the whole point of the letter; the season was only ever the excuse.

Closing

A zansho-mimai says nothing much.

Still hot. Are you well? I am well. Take care of yourself. Truly, that is all of it. There is no business in it, so no reply is needed either.

But having no business is precisely what lets it carry something: I had no reason to contact you, and I thought of you anyway. A message with a reason can be sent any day of the year. A message without one usually needs the calendar to nudge you.

Autumn on the calendar, summer in the air. Into those few unresolved weeks, Japan slipped a letter. It was the misalignment itself that gave people something to write about.

If, at the end of a Japanese summer, someone crosses your mind — you need nothing long. “Still hot, isn’t it. Are you well?” That single line is, already, a Japanese seasonal greeting.

Sources

National Astronomical Observatory of Japan, Almanac for Reiwa 8 (2026), Twenty-Four Solar Terms — https://eco.mtk.nao.ac.jp/koyomi/yoko/2026/rekiyou262.html
Wikipedia (Japanese), “暑中見舞い” — https://ja.wikipedia.org/wiki/暑中見舞い
Wikipedia (Japanese), “夏のおたより郵便葉書” — https://ja.wikipedia.org/wiki/夏のおたより郵便葉書
Midori, “The origins of the shochu-mimai” — https://letter.midori-japan.co.jp/special/summer/origins/
Midori, “How to compose a shochu-mimai / zansho-mimai” — https://letter.midori-japan.co.jp/special/summer/format/
Ringbell, “Zansho-mimai: from when until when?” — https://www.ringbell.co.jp/giftconcierge/2054
Tokyo Gas Uchikoto, “Zansho-mimai: timing, writing and manners” — https://uchi.tokyo-gas.co.jp/topics/2586
Mitsukoshi Isetan, “Summer greeting etiquette during mourning” — https://www.mistore.jp/gifts/summergift/summergift_mochu_manner/
ITmedia NEWS, “Kamome-ru discontinued from FY2021, Japan Post announces” — https://www.itmedia.co.jp/news/articles/2103/30/news087.html