Why Does “Reading Mackerel” Mean Lying About Your Age in Japanese?

In Japanese, 鯖を読む (saba o yomu) is a familiar expression for fudging a number—especially your age.

Taken literally, however, it looks bizarre:

鯖 (saba) = mackerel
読む (yomu) = to read

So why would “reading mackerel” mean making yourself a few years younger?

The answer leads back to older meanings of Japanese words, Edo-period fish markets, and several competing etymological theories. The important point is that the story is more interesting—and less certain—than the usual one-line explanation suggests.

First: yomu did not only mean “to read”

The first clue is the verb 読む (yomu).

Today, Japanese learners encounter it mainly as “to read”: you yomu a book, a newspaper, or a message. But historically, yomu also meant to count.

Japanese dictionaries preserve this older sense, with examples involving counting days, months, nights, and objects one by one.

So historically, 鯖を読む makes more sense if we understand it not as “read mackerel,” but as:

“count mackerel.”

That solves half the mystery.

The other half is harder: why would counting mackerel become associated with inaccurate or deliberately manipulated numbers?

The expression was already in use in the Edo period

The expression is not modern slang.

The Nihon Kokugo Daijiten records a 1753 example in which saba o yomu was already being used figuratively in the sense of misrepresenting a count.

That means the expression was established in Japanese more than 270 years ago.

What we cannot say with the same confidence is exactly how it originated. Several explanations survive, and dictionaries generally treat the etymology as uncertain.

Theory 1: mackerel had to be counted quickly

This is the best-known explanation.

Mackerel is relatively perishable. Before modern refrigeration, merchants had good reason to move a large catch quickly.

According to this theory, fish sellers counted mackerel at speed. Rapid counting could naturally become inaccurate—and it could also make intentional miscounting easier.

Over time, “counting mackerel” became associated with a conveniently unreliable count.

It is an appealing image: a busy market, boxes of rapidly spoiling fish, merchants calling out numbers, and a total that might be just a little more flexible than it should be.

But this is not the only explanation.

Theory 2: two mackerel could be counted as one unit

Traditional Japan also had a preserved product called 刺鯖 (sashi-saba).

Mackerel were prepared and arranged in pairs, and historical descriptions note that a pair could be treated as one counting unit called an 一刺 (issashi).

That creates an obvious ambiguity: are you counting individual fish, or units made from pairs of fish?

Some explanations of saba-yomi connect this old counting convention with the later idea of numbers that do not quite match the actual number of fish.

Theory 3: perhaps saba was not originally mackerel

A particularly interesting alternative concerns the old word 魚市 (isaba), associated with fish markets and the fish trade.

Some etymological explanations connect the expression with 魚市読み (isaba-yomi), a rapid style of counting used in the fish trade. Under this theory, isaba-yomi eventually shortened to saba-yomi, and the familiar character 鯖—mackerel—became associated with it later.

If this is correct, the expression may have originally meant something closer to “fish-market counting” than specifically “counting mackerel.”

This theory is one reason it is better not to present the common “mackerel spoils quickly” story as proven fact.

So which theory is correct?

We do not know for certain.

What the major explanations share is a similar historical setting: fish, markets, rapid counting, unusual counting units, and commercial transactions in which numbers could become flexible.

By 1753, saba o yomu was already being used to mean misrepresenting a number. The exact path by which that meaning developed remains uncertain.

That uncertainty is not a weakness in the story. It is part of the story.

It was not originally only about age

Today, 鯖を読む is especially familiar when talking about age.

Someone who is 42 but claims to be 39 is サバを読んでいる (saba o yonde iru).

But the expression itself is broader. It means manipulating a number for your own convenience. Depending on context, it can apply to quantities, money, height, weight, or other figures.

There is even a playful modern expression, 逆サバ (gyaku-saba, “reverse saba”), for claiming to be older rather than younger.

The fish has disappeared completely from the situation. What remains is the idea of a suspiciously convenient number.

Is there an English equivalent?

There is no exact English equivalent involving fish.

For the general meaning, English has expressions such as “fudge the numbers” or “massage the figures.”

For age specifically, someone might “shave a few years off their age.”

So the concept itself is not uniquely Japanese. What is distinctive is the linguistic fossil preserved inside the Japanese phrase.

A casual modern sentence such as:

ちょっとサバ読んだ。 Chotto saba yonda.

roughly means:

“I fudged the number a little.”

Usually, nobody is thinking about an actual mackerel.

An Edo-period fish market hiding inside everyday Japanese

This is one of the pleasures of ordinary language: expressions can survive long after the world that produced them has disappeared.

Modern Japan has refrigeration, electronic scales, barcodes, and computerized inventory systems. Yet someone making themselves three years younger can still be accused of counting mackerel.

Whether the expression ultimately came from hurried merchants, paired preserved fish, isaba market counting, or some combination of these traditions is still debated.

But beneath a casual joke about age lies the vocabulary of an older commercial Japan.

Sometimes history survives not in famous temples or museum displays, but in the strange little phrases people use every day without thinking about them.

And somewhere inside 鯖を読む, an Edo-period fish merchant may still be counting just a little too quickly.