Friday 13th and Superstition

FridayaThe13thby Jerry Richardson2/18/15
Does bad luck come in threes?  This year, 2015, there are 3 Friday 13ths; February 13, 2015, March 13, 2015, and November 13, 2015.  What has caused Friday 13th to be viewed as an unlucky day?

I will discuss the Friday 13th superstition and superstition in general, in this essay; and at the end show exactly how to know when and how many Friday 13ths there can be in a given year.

Most likely the stigma associated with Friday 13th is due to an intersection of two superstitions: The supposed unluckiness of the day Friday with the supposed unluckiness of the number 13;  so with Friday 13th we get a double whammy—shades of Evil-Eye Fleegle (Li’l Abner).

There is even a long polysyllabic word for the fear of Friday 13th, paraskevidekatriaphobia (hear it pronounced), and one for the fear of the number 13, triskaidekaphobia (hear it pronounced).  Don’t worry I won’t use these words again.


Some writers have suggested that the superstition concerning the day Friday can be contributed to Christian sources; but this doesn’t seem very likely.  It could be, because Christ was crucified on Friday (most people agree) and hence Friday could have been seen, by some, as an unlucky day.  But this doesn’t quite match the history of the use of Friday by early Christians and the labeling of crucifixion-Friday as “Good Friday.”

From the earliest times the Christians kept every Friday as a feast day; and the obvious reasons for those usages explain why Easter is the Sunday par excellence, and why the Friday which marks the anniversary of Christ’s death came to be called the Great or the Holy or the Good Friday. The origin of the term Good is not clear. Some say it is from “God’s Friday” (Gottes Freitag); others maintain that it is from the German Gute Freitag, and not specially English. Sometimes, too, the day was called Long Friday by the Anglo-Saxons; so today in Denmark.
Good Friday

Numerous sources I have read have stated that in the early days of Rome, Friday was execution day; and later in Britain Friday became the Hangman’s day.  Spectacular events such as public executions could certainly have served to color people’s opinion of the favorableness of the day.

It has also been suggested by some that Friday-phobia could have something to do with a Christian-distaste for the pagan origin of the name Friday: The Norse Goddess Frigg or Frige in Old English; hence Frige’s day or Friday.

But I don’t think that attributing the superstition to a Christian-distaste of the pagan-origin of the name of one week-day makes sense, because all the other week-day names came either from Teutonic deities (such as Germans or Scandinavians) or from Roman deities—and I have not found documentation of any organized Christian outcry. In addition, the earliest written reference that I can find where Friday is associated with bad luck is in Chaucer’s Canterbury Tales.

And on a Friday fell all this mischance.
Canterbury Tales, The Nun’s Priest’s Tale

Chaucer alluded to Friday as a day on which bad things seemed to happen in the Canterbury Tales as far back as the late 14th century (“And on a Friday fell all this mischance”), but references to Friday as a day connected with ill luck generally start to show up in Western literature around the mid-17th century:

      • “Now Friday came, you old wives say, Of all the week’s the unluckiest day.”   (1656)

From the early 19th century onward, examples abound of Friday’s being considered a bad day for all sorts of ordinary tasks, from writing letters to conducting business and receiving medical treatment:

      • “I knew another poor woman, who lost half her time in waiting for lucky days, and made it a rule never to . . . write a letter on business . . . on a Friday — so her business was never done, and her fortune suffered accordingly.”   (1804)
      • There are still a few respectable tradesmen and merchants who will not transact business, or be bled, or take physic, on a Friday, because it is an unlucky day.”   (1831)

Chaucer and Friday 13th

There is really no consensus that I can find, on exactly when or how the superstition of unluckiness of Friday began. It would be easy to hypothesize that the notion of unlucky Friday was initiated by the popular poet Chaucer in the 14th century; but my hunch is that it precedes that date and that Chaucer worked-in an already existing superstition into the Nun’s Priest’s Tale. I favor the execution day/hangman day theory as an earlier primary-cause of Friday-phobia; but there is no hard evidence for that.


We have already discussed how the Crucifixion of Christ could possibly be linked to the notion that Friday is unlucky.  In addition to that, the “last supper” of Christ with his 12 disciples has been suggested as a reason for the number 13 superstition—Christ plus the 12 equals 13 and Judas left and after his betrayal of Jesus, he hanged himself.  There is also a Norse myth where having 13 diners seated around one table results in the death of one of the diners.

Much of the distaste for 13 is doubtlessly grounded in numerology.  In biblical numerology, the number 12 indicates something that is finished or complete and which forms a perfectly harmonious unity; therefore the number 13 represents the overdoing and hence the spoiling of completeness.

In the King James Version of the Bible, the word twelve is found 189 times in 165 different verses.  Wherever it is found, there is an unarticulated sense of completeness surrounding it:  “twelve disciples”; “twelve baskets full”; “twelve legions of angels”; “twelve tribes of Israel”; “twelve thrones”; “twelve years old” (Jesus in the temple).

The numerological significance of 12 is that it is the product of 3 * 4.  The number 3 is the number of spiritual completion, e.g., the Trinity; whereas the number four is the number of creations’ completeness, e.g., the 4 directions of the compass; hence 4*3 = 12 is the number of completeness of the rule of God relative to his creation.

In addition 12 can be seen as a symbol of completeness in more places than the Bible; there are 12 months in a year, 12 signs of the zodiac, 12 labors of Hercules, and 12 gods of the Olympus.

So how did Friday 13th get its bad reputation?

The earliest written reference appears in the biography of Gioachino Rossini who, according to his 1869 biography, written by Henry Sutherland Edwards, which stated, “like so many Italians, he regarded Fridays as an unlucky day and thirteen as an unlucky number, it is remarkable that on Friday 13th November he passed away.”
Friday 13th, Unlucky

Dossey…a folklore historian and author of Holiday Folklore, Phobias and Fun, said fear of Friday the 13th is rooted in ancient, separate bad-luck associations with the number 13 and the day Friday. The two unlucky entities ultimately combined to make one super unlucky day.  Dossey traces the fear of 13 to a Norse myth about 12 gods having a dinner party at Valhalla, their heaven. In walked the uninvited 13th guest, the mischievous Loki. Once there, Loki arranged for Hoder, the blind god of darkness, to shoot Balder the Beautiful, the god of joy and gladness, with a mistletoe-tipped arrow. “Balder died and the whole Earth got dark. The whole Earth mourned. It was a bad, unlucky day,” said Dossey. From that moment on, the number 13 has been considered ominous and foreboding.
Unlucky 13

A fear of Friday 13th as an unlucky day is just one of many human superstitions.  A typical definition of superstition is the following:

Although superstitions occur in a variety of forms, they may be defined as irrational beliefs that an object, action, or circumstance that is not logically related to a course of events influences its outcome.
Keeping Your Fingers Crossed

There are basically two types of superstition: 1) Positive, and 2) Negative.  A positive superstition is the belief that if a person performs some action, even though there is no known or explicable causal connection, a good or positive result will ensue.  Athletes and students are especially known for this type of superstition:

Throughout his entire career, for example, basketball player Michael Jordan wore his old blue University of North Carolina shorts underneath his National Basketball Association uniform, for good luck. Similarly, tennis player Serena Williams once admitted wearing the same pair of socks throughout a tournament, and golf pro Tiger Woods wears a red shirt on tournament Sundays, which is usually the last (and critical) day of a tournament. Indeed, many people develop and observe superstitions, such as crossing their fingers (Vyse, 1997), knocking on wood (Keinan,2002), or carrying a lucky charm (Wiseman & Watt, 2004).

Keeping Your Fingers Crossed

A fear or apprehension of Friday 13th is arguably the best known and most prevalent of American superstitions.  It is typical of a negative superstition—to be avoided if possible—in that it is something that is thought to bring bad (negative) results as opposed to good (positive) results.

Many people, especially modern-day atheists, often wish to conflate religious beliefs with superstition.  But of course this conflation hinges upon the primary defined-essence of superstition: “Irrational” beliefs. The notion of “irrational” (not consistent with reason) is obviously a pejorative term but also is very subjective and it is often difficult or impossible to demonstrate or prove any objective labeling of some thought or belief as “irrational.”

As human beings, we all hold many unproven and perhaps unprovable beliefs; and even though any specific one of those beliefs may be incorrect it is not necessarily irrational (without reason).  I believe that a Friday 13th-phobia falls into this category;

I personally assume that this belief is irrational, but I cannot prove it.

The preceding discussion perhaps accounts for the fact that common superstitions such as fear or apprehension of Friday 13th never seem to go away—the accounting is that there is, in fact, no actual way to prove or demonstrate, to everyone’s satisfaction, that there is no reason to fear Friday 13th as bringing about bad occurrences.

Who do you suppose could have convinced Michael Jordan, and how, that wearing his old blue University of North Carolina shorts underneath his NBA uniform did not, in fact, enhance his basketball performance?  And the amusing thing is, according to at least one Association for Psychological Science (APS) research report superstitions may indeed be beneficial:

These findings are an initial demonstration of the performance benefits of superstitions. Individuals indeed performed better if a good-luck-related superstition was activated.
Although superstitions are often seen as inconsequential creations of irrational minds, it is possible that the extra effort invested into the execution of superstitions may also turn into an advantage for the individuals concerned. In fact, researchers have speculated that engaging in superstitions regulates psychological tension and creates a feeling of
control and a sense of predictability in otherwise chaotic environments…We propose that over and above these possible psychological benefits, superstitions also entail directly observable performance benefits.
Keeping Your Fingers Crossed

I am reasonably sure that most people do not believe that any positive, or negative, effect that may arise from exercising a superstition comes about because of some unseen direct causal-link.  However it doesn’t take much of a stretch of the imagination to give credence to the idea that the exercise of a superstition might carry with it a psychological benefit.

In medicine, the placebo effect is very well-known and in double-blind drug-testing experiments has to be considered.  It has been demonstrated often enough to be uncontroversial that a simple sugar-pill (not identified as such) given to someone as a supposed “medicine” may have as good or better effect than the actual medicine given to others in the double-blind test.  What is the cause for this?  Undoubtedly some powerful psychological effects that are still imperfectly understood.

The placebo effect is not deception, fluke, experimenter bias, or statistical anomaly. It is, instead, a product of expectation. The human brain anticipates outcomes, and anticipation produces those outcomes. The placebo effect is self-fulfilling prophecy, and it follows the patterns you’d predict if the brain were, indeed, producing its own desired outcomes.
The Placebo Effect

A German doctoral (PhD) dissertation of Superstition, available online, provides experimental and statistical facts and related research to support the following conclusion:

Superstitious thoughts or behaviors have been demonstrated to occur frequently and persistently in our current population. Typically, they are held or performed in the context of an important performance task with the aim to gain good luck or prevent bad luck. However, to date, little is known about the reason for the maintenance of this seemingly irrational phenomenon, its psychological functions, or its behavioral consequences. The current analysis suggests that superstitions exert a causal influence on subsequent task performance…Furthermore, I argue that this influence is explained by the underlying mechanism of increased levels of perceived task-specific self-efficacy beliefs.
The Influence of Superstition

Self-efficacy is a much studied and discussed psychological concept.  In order to verify that for yourself just Google self-efficacy; I got the following: About 8,570,000 results (0.23 seconds).

Self-efficacy is the key concept in Bandura’s social cognitive theory (Bandura, 1977, 1986) and refers to one’s perceived capability to produce results and to attain designated types of performance (Bandura, 1977, 1997…the beliefs people hold about their capabilities can often be a better predictor of their behavioral outcomes than what they are actually capable of accomplishing.
The Influence of Superstition

My personal explanation for superstitions is that they result from the fact that mankind is a casualty-seeking being.  We want to know and understand what causes anything to happen.  If we cannot, within our own powers of observation, or via trial-and-error, or from a trusted authority discover the cause of some occurrence or result, then we will often hypothesize that there is a cause that we cannot see—and this absolutely may be true.  In addition, not only will we hypothesize the unseen cause, we will begin to seek to discover it.

We now know from the world of quantum physics that the decay of a sub-atomic particle—which is described as spontaneous—is either uncaused or has a cause that so-far cannot be accounted-for.  I believe in the latter explanation but cannot prove it; the reason for my belief is that I believe in the Leibniz principle of sufficient reason (for every fact F, there must be an explanation for why F is the case); I simply do not believe that uncaused is a reasonable explanation for any physical event—in addition, I believe there is only one uncaused entity, God.   I claim that my belief is not irrational (without reason); hence not superstitious.

Does my belief differ in kind from Michael Jordan’s belief in the helpfulness of his old basketball shorts?  Neither of us has proof.  In Michael Jordan’s case he seemed unwilling to accept the completely sufficient explanation—to most of us—for his basketball success: His own talent and industry. But for Michael that didn’t seem to be enough.  For most of mankind, there always seems to be that shadow of transcendence: Something is there that we cannot see; and we want to find a way to connect with it.



Periodically someone on the Internet will ask how many Friday 13ths there are in a particular year, and how many there can be.  And just as frequently someone else on the Internet will provide the answer; however, I have noticed that they never seem to explain or reference someone else who will explain how to arrive at the answer.

Question: How many Friday 13ths are there in 2015 and when will they occur, and how many Friday 13ths can there be in a year? Answer: There are 3, which is the maximum number that can occur in a year; and the dates of occurrence are February 13th, March13th, and November 13th.  How did I arrive at the answer just given?

There are 14 possible configurations of days in a Gregorian year; 7 unique configurations for a LEAP YEAR; and 7 different, unique configurations for a NON-LEAP YEAR resulting in a total of 14 configurations.

Below is a table that shows all 14 of these configurations (I will explain the table in the discussion below the table):



Any given month-day (for example the 13th of the month) will occur in a specific month on a certain week-day (for example Tuesday).  The week-days are numbered as follows: (0 = Sunday, 1 = Monday…6 = Saturday).  The rationale for the use of these numbers is that they represent the MOD (Modular) 7 equivalent of the numbers 1 – 7 (the MOD 7 equivalent of 7 is 0).  Most people understand this as a type of “clock” arithmetic, which is taught to most elementary math students.

Let’s look at how this “clock” arithmetic works in the table above.  Suppose the month-day 13 occurs in January on Tuesday, which is the case for this year, 2015. Examine the top row of DAY OF THE WEEK NUMBERS in the NON-LEAP YEAR portion of the table above, the row opposite JAN, and you will find the week-day number 2 under the abbreviation for the week-day name, TUE.

Now, If I wish to know when the month-day 13 will occur in February, I have to count (add) 31 month-days (days in January) from the week-day 02; this is because I have to finish with the 18 days left in January and then count (add) the 13 days that I want in February which equals 31 (18 + 13) days, the number of month-days in the month of January.  When I perform this count, I get the number 33 which is equivalent to 5 MOD 7 (5 is the remainder when I divide 33 by 7).  Examine the second row, the row opposite FEB, in the table above and under TUE you find 5 which is the week-day number for Friday; so in 2015 the month-date 13 will fall on Friday in February if the 13th falls on Tuesday in January.

The arithmetic just discussed can be performed quickly by using the MOD 7 number for 31, in the third column of the table, which is 3 (31 MOD 7 = 3); then the modular arithmetic become 3 + 2 = 5 (MOD 7); and 5 is the week-day number for Friday.

The same procedure is used for the rest of the year to complete the table.

Now examine the entire column in the table under the week-day TUE, and look for 5 (Friday).  You will find 3 5s (Fridays).  They occur in February, March, and November.

At the bottom of the table above, I have tabulated the number of occurrences of each week-day for each calendar configuration. Under the NON-LEAP YEAR part of the table you will find that Friday occurs 3-times only once in this configuration; occurs 1-time in 3 different configurations, and occurs 2-times in 3 different configurations.

Examine the LEAP YEAR side of the table which shows that if a month-day (in our discussion the 13th) occurs on week-day 5 (Friday) in January it will occur 3 times during that year, January 13th, April 13th, and July 13th.

The tabular numbers are good for any month-day not just the 13Th.  For example in 2012 (a LEAP YEAR), January 1st was on Sunday.  If we look under the 0 (SUN) column in the LEAP YEAR side of the table we see that in 2012 the month-day, in this case 1st, occurs on the week-day 0 (Sunday) on January 1st, April 1st, and July 1st.

To find specific results, a person must know what week-day a specific month-day occurs in come specific month.  There are numerous computer algorithms to compute this information, or of course, one can always look at a calendar. An Excel spreadsheet can automate procedures for use of the above information.  From such a spreadsheet we can quickly obtain information such as the following:


© 2015, Jerry Richardson • (2220 views)

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10 Responses to Friday 13th and Superstition

  1. Timothy Lane says:

    I have various observations to make here. First, I will note that in the “Pigs in Space” portion of the old Muppet Show from the late 1970s, they would identify the characters in various ways. On one occasion, they referred to Dr. Julius Strangepork as “triskaidekaphobic”. (On another occasion he was called “sesquipedalian”, which is appropriate for this discussion.)

    The discussion of the placebo effect reminds me of a scene in the movie Bull Dirham in which Crash Davis, when the woman complains that he had gotten Nuke LaLoosh to stop bedding her, explains the delicate psychological effects and says that if a player thinks something will help (or hurt) his performance, he should act on those feelings.

    There is also a story that someone once visited Niels Bohr and noticed that he had a horseshoe over his door. The visitor wondered if Bohr could actually believe in the superstition, and Bohr answered that he didn’t — but he was informed that it would bring good luck even if he didn’t believe in it. (An interesting scene involving a horseshow over a door occurs in an episode of the mid-1960s Batman show. The villain Shame had a horseshoe over his door for good luck — and at a key point it fell off, conking his girlfriend Calamity Jan over the head. So much for good luck.)

  2. Jerry Richardson says:


    Thanks much for your, as usual, very appropriate and thoughtful comments. I am overdue in expressing my appreciation for the way you always manage to find the time and take the effort to comment on any article published in Stubborn Things.

    I sincerely hope you do not stop this very encouraging and helpful practice. I always feel like that if I make some drastic spelling or factual blunder, you will spot it and point it out in the spirit of helpfulness. I appreciate that.

    Thanks again.

  3. Rosalys says:

    Very interesting and enjoyable read, Jerry. That is up until the Determining the Occurrences portion. Still interesting, but I don’t know about enjoyable. I am exceedingly glad to not be superstitious this morning, as I would feel compelled to memorize the formula if I were!

    • Jerry Richardson says:


      Very interesting and enjoyable read, Jerry. That is up until the Determining the Occurrences portion. Still interesting, but I don’t know about enjoyable. —Rosalys

      Thanks for the comments. Your statement about the Determining the Occurrences is the reason I tacked-it on to the end, actually as an appendix even though I didn’t label it as that. Being an old math and computer person, I know full-well that it will not be many-people’s cup of tea. However, I did and do hope that it will not prevent people from reading and enjoying the first part. And as far as memorizing it, I don’t even do that.

      • Timothy Lane says:

        I must confess I only scanned that section myself, though I did read the section on computing days of the week for any year that Charles Lutwidge Dodgson worked up, and which is explained in full in Robin Wilson’s Lewis Carroll in Numberland, which I suspect you would enjoy. You might also enjoy Georges Ifrah’s Universal History of Numbers.

  4. Jerry Richardson says:


    Thanks for the book tips. I just ordered a Kindle copy of Lewis Carroll in Numberland. I thought I had a paperback copy of that purchase several years ago, but cannot locate it. I have so many hard-copy books but no indexing system; so if I can find a hard copy that I know or thought I had, I just buy a Kindle version if it’s available. Do you have this problem? If so, how do you manage it?

    • Timothy Lane says:

      I definitely have the problem, and haven’t worked up a good way of dealing with it. In fact, there have been a few cases here where I wanted to comment on something by mentioning an item in a book that I then couldn’t locate. It can be very frustrating. A lot of my books can be located readily enough, but a lot of others are simply . . . somewhere.

  5. Jerry Richardson says:

    What is the relationship between superstition and enchantment with a mythical, fictitious character; for example Slender Man?

    They are related.

    Superstition is the mistaken attribution of causality; not correctly connected with reality. Fantasy is imagination that is unrestricted by reality. Both Superstition and fantasy miss or ignore true reality.

    Superstitions and fantasies are not always harmless. But is there a way to discern the difference between non-harmful and harmful superstitions and fantasies? Yes there is, and the answer is found in the Bible. What is necessary is the discernment between what is evil and what isn’t. The Bible (Jesus speaking) clearly describes what this essence is:

    The thief comes only to steal and kill and destroy; I came that they may have life, and have it abundantly.
    —John 10:10 NASB

    When Jesus uses the word “Thief” in the context above he is talking about false “mediators of salvation”; we can interpret that, without contorting the scripture, as being anyone who teaches a lifestyle that is essentially evil (satanic). And the way we can discern the evil of their teaching is that their advice and examples will involve some form of stealing (taking something that does not belong to you), killing (murder), or destroying (something of value).

    The evil of the fantasy of Slender Man can thus be identified.

    The Slender Man (also known as Slenderman) is a fictional supernatural character that originated as an Internet meme created by Something Awful forums user Eric Knudsen (a.k.a. “Victor Surge”) in 2009. It is depicted as resembling a thin, unnaturally tall man with a blank and usually featureless face, wearing a black suit. Stories of the Slender Man commonly feature him stalking, abducting or traumatizing people; particularly children. The Slender Man is not confined to a single narrative, but appears in many disparate works of fiction, mostly composed online.

    Slender Man

    Here is a report of an actual instance of the harm that this fictional character has done in the lives of three young girls.

    It is almost a year since Payton Leutner, then 12, was lured into woods near her home in Waukesha, Wisconsin in late May and brutally stabbed 19 times by friends hoping to win the approval of sinister fictional character, the Slender Man.

    Just one day earlier Payton had excitedly gone to a sleep-over with Morgan Geyser and Anissa Weier, both 12 at the time of the attack, unaware of what police have described as the five month plan concocted by her best friends intent on murdering her. The slumber party was to celebrate Geyser’s twelfth birthday.
    Page after page of the books, seen by the court, revealed images including a young cat-like girl armed with a scythe standing over a dead girl with a speech bubble that says, ‘I love killing people.’ Elsewhere the 12-year-old wrote of her admiration of the Slender Man, whom she allegedly sincerely believed to live in a mythical Mansion in the woods.

    Slender Man stabbing victim

  6. Jerry Richardson says:

    The Chinese have their own particular, and popular, brand of superstition: Animal-sign astrology.

    Chinese were seeing in the Year of the Sheep on Thursday, but with fortune-tellers predicting accidents and an unstable economy and some parents-to-be fretting over the year’s reputation for docile kids, it wasn’t exactly warming everyone’s heart.

    This animal sign, which comes once every dozen years, can be said to have an identity crisis. Known variably as the Year of the Goat, Sheep or Ram, the sign’s confusion stems from its Chinese character, “yang,” which broadly describes any of the ruminating mammals, with or without horns.
    Still, Xinhua is going with “Year of the Sheep” in its English-language reports rather than “Year of the Goat.”

    During the seven-day holiday that started Wednesday, the world’s second-biggest economy largely shuts down.
    Astrologists interviewed said this year would bring a volatile economy, more transport accidents and windy natural disasters such as tornadoes in the United States and typhoons to Southeast Asia.

    For China, which doesn’t get tornadoes, that means air pollution, “coming in with dirty air currents and affecting everyone’s lives,” said Shanghai-based astrologer Dong Jialing.

    Happy Ewe Year

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