Por el canto de un duro

by the skin of one's teeth; **by the skin of one's teeth**; **by a whisker**; **by a hair's breadth**; **by a very narrow margin**; **only just**

Por el canto de un duro means by a very narrow margin, by the skin of one's teeth, or almost not at all.

It is used when someone narrowly avoids something, narrowly succeeds, or comes very close to an undesirable outcome.

• someone narrowly escapes danger
• someone just manages to achieve something
• a result is decided by a very small difference
• something almost goes wrong
• someone barely avoids missing an opportunity

The expression refers to the duro, a popular name for the old Spanish five-peseta coin.

The canto is the edge or rim of a coin. The edge is extremely narrow compared with the coin's diameter.

Therefore, to succeed por el canto de un duro is to succeed by a tiny margin, almost as though the difference between success and failure were no wider than the edge of a coin.

The expression belongs to the large group of Spanish idioms that preserve references to old Spanish currency.

The expression is normally used to emphasise just how narrowly something happened.

Compare:

Aprobé por poco.

→ I passed by a small margin.

with:

Aprobé por el canto de un duro.

→ I only just passed / I passed by the skin of my teeth.

The second is much more vivid and colloquial.

The expression can refer both to success and to avoiding failure or danger.

The duro was not officially the name of the coin: it was the popular name for the five-peseta coin.

The word duro came from the old peso duro, a historical Spanish silver coin. Even after the peseta replaced earlier monetary systems, duro remained in popular speech as a synonym for five pesetas.

Thus, an expression such as:

No tengo ni un duro.

literally means:

I don't have even a duro.

and came to mean simply:

I have no money.

The disappearance of the peseta has made these expressions increasingly historical, but por el canto de un duro remains understandable and is still occasionally used.

Do not translate:

Aprobé por el canto de un duro.

literally as:

I passed by the edge of a duro.

Natural translations include:

I only just passed.

I passed by the skin of my teeth.

I scraped through.