Friday 13th – Black Friday –  is acknowledged as an unlucky day across a variety of countries and cultures. However, not everyone sees the 13th as negative and even those people who do, find it difficult to agree on the origins of the belief.

13 people sat down for The Last Supper

13 people sat down for The Last Supper Image by Waiting For The Word / CC BY 2.0

Part of the reputation of the number 13 is the significance of the number 12 which makes it into patterns and habits across cultures and countries. There were 12 apostles of Jesus, 12 months in the year, 12 gods of Olympus, 12 hours of the clock, 12 tribes of Israel, 12 Descendants of Muhammad Imams. Therefore, the 13th number is seen as an outsider, an addition that throws things out of kilter and disrupts the harmony of the number 12. Judas was the 13th person at the last supper.

Friday 13th features heavily in both biblical and popular culture throughout history, with Geoffrey Chaucer including stories about its bad luck in The Canterbury Tales, as well as Franklin D Roosevelt refusing to make decisions on Friday 13th.

The 13th number has gotten such a bad reputation over the years, that some apartment buildings get rid of the number entirely, whilst it’s generally frowned upon to have a dinner party of 13 people, the superstition being that the first person to leave the table will encounter misfortune.

Numbers often get ascribed negative or superstitious significance, even if it’s not the number 13. In Italy the number 17 is considered very unfortunate. The superstition supposedly dates back to ancient Rome, when the Roman numeral for 17 XVII, could be shuffled into saying ‘vixi’ or ‘i have lived’, implying therefore death.

In China the number 4 is considered to bring bad luck. Hospitals won’t have number 4 rooms, buildings often skip the number 4 floor. This is because the number 4 when pronounced in Chinese sounds very like the word for death, and the possible confusion between the two could bring bad luck.

In Japan the word for 9 sounds incredibly like the word for ‘torture’ and so the Japanese avoid it for houses and hotel and hospital rooms.

The number 13 is unlucky when compared to the number 12

The number 13 is unlucky when compared to the number 12 Image by Dave Bleasdale / CC BY 2.0

The fear of Friday the 13th though is widespread enough that it has its own name – Paraskevidekatriaphobia. This describes the irrational and powerful fear of Friday 13th as an actual psychosomatic phenomenon. It’s been documented that there is an increased number of people checking into hospital’s ERs on Friday 13th. But according to Doctor Caroline Watt who spoke to The Telegraph, the reason there are more incidents is because people are more anxious on Friday the 13th due to its reputation: “It is like telling someone they are cursed. If they believe they are then they will worry, their blood pressure will go up and they put themselves at risk.”

So perhaps the best advice is, keep calm and ignore Friday 13th!