Get into an elevator in a Korean high-rise and look at the panel. The buttons might run 1, 2, 3, F, 5, 6. That F is not a mislabel or a mechanical floor. It stands for “Four,” a polite substitution for a number the building would rather not print. Korean cultural resources describe exactly this: in many South Korean hospitals the fourth floor is omitted, or the letter F stands in for the fourth floor instead.

I find this interesting because it sits at a strange intersection. It’s a superstition, yes, but one with a completely rational explanation, and one that has been poured into concrete and steel.

Where the F actually shows up

The substitution is most visible in tall buildings, but it doesn’t stop at the elevator panel. In many South Korean buildings, the fourth floor is either labelled F or skipped altogether, and the habit extends inward to room numbering.

The taboo runs strongest in exactly the places where people are already thinking about mortality. Korea.net notes that while fourth floors may sometimes appear in ordinary buildings, they are generally not found in Korean hospitals.

The practice varies. Not every building does it, and the exact treatment differs — some skip the number, some swap in the F. It is a widespread convention rather than a strict rule.

Why four sounds like death

The reason is linguistic, and it’s cleaner than most superstitions get to be.

The Sino-Korean word for four and the Sino-Korean word for death are both pronounced sa (사). They are written with different Chinese characters — 四 for four and 死 for death — but that difference lives on the page, not in the ear. As a Korea.net article explains, the two words sound identical when spoken.

What makes the Korean case sharper than its Mandarin Chinese cousin is tone, or the lack of it in standard Korean. Mandarin has the same rough pairing, but four and death are distinguished by tone, so they sound close rather than identical. In Korean, the homophone is exact, which is probably part of why the avoidance took such firm hold.

How far the habit reaches

Beyond floors and rooms, the number turns up avoided in small everyday choices. Gift-giving is a good example. Gifts and household sets may come in groups of three or five rather than four, and people avoid giving gifts in fours for celebratory occasions. The same instinct can show up in apartment unit numbers.

There’s a real-estate wrinkle here too, though it needs care. An academic study of the Greater Vancouver housing market found that, in neighbourhoods with an above-average share of Chinese residents, houses with addresses ending in four sold at a 2.2% discount, or about CAD$8,000 at the sample’s average price. That is Canadian evidence, not a measured Korean discount, but it shows that tetraphobia can affect property values.

Science and superstition

What keeps pulling my attention is the gap between how easily people can explain this and how little that explanation dissolves it. Awhy the fourth floor says F and you’ll get a clear, almost cheerful answer about a homophone. And then the F stays on the button anyway.

There’s even a scientific chapter to this, and it cuts against the superstition. A 2001 study in the BMJ by sociologist David Phillips reported what its authors called a “Hound of the Baskervilles effect,” claiming that deaths from chronic heart disease among Chinese and Japanese Americans were around 13% above expected on the fourth of the month. It’s a striking idea. It also didn’t clearly hold up. A reanalysis by Gary Smith found no unusual fourth-day peak using broader comparisons, while a study by N. S. Panesar and colleagues found no excess cardiac deaths on the 4th, 14th or 24th in Hong Kong.

Writing for McGill’s Office for Science and Society, science communicator Jonathan Jarry sums up the trajectory bluntly: “One study shows that more East Asians die on ‘death day’, the fourth of every month. But better studies show this Baskerville effect to be nothing more than an illusion.”

That is a failure to replicate the original statistical pattern, not proof that stress can never affect health. But the specific prediction — that more East Asians die on the fourth because of tetraphobia — does not appear in the stronger follow-up data.

Closing thoughts

The F isn’t hiding anything; everyone knows what it means. It’s there because avoiding the shape of the number costs almost nothing, and printing it would mean insisting on a point nobody feels like insisting on. So the number stays quietly absent, and the architecture keeps its manners.