PRIME 13

I think that '13 is unlucky' was a cover story to prevent people from discovering that 13 was the number that could break early banking codes.

13 is the first prime number that is relatively difficult to multiply and divide. With no calculators and dependent upon a few encoding and decoding people, 13 would be a reasonable choice for a prime number based code.

The 'unlucky 13' probably started as an 'in' joke, because people who talk about a secret banking code can get very unlucky. %<)  It worked so well as a superstition that it actually made people afraid to use the number 13. The bankers must still be giggling from beyond the grave.

I am certain that 'the seven years bad luck to break a mirror' was made up by a merchant trying to get curious people to be VERY careful with the fragile early mirrors. Remember that NO ONE had seen a clear image of themselves. EVERYONE wanted to see themselves for the first time.

Of course, the 'bad luck to walk under a ladder' was started by builders who could not get boys to understand how dangerous ladders can be.

Maybe we can start a superstition that would keep people from answering Nigerian email scams.

Meanwhile, as usual, the non supertitious can make a lot of money playing on your supertitioms.