Put simply, a character flips a coin, which lands on its edge. This generally happens for one of three reasons:
- The coin just happens to land on its edge due to (ridiculously miniscule) chance. Law of Conservation of Detail means this is almost never the reason in fiction.
- The character is using the coin flip to make a decision. When the coin lands on edge, they take it as a signal either to be indecisive or to Take a Third Option. This frequently results in the best of both options being employed. Hilarity Ensues in a comedy series. Screw Destiny follows if the character was facing a Sadistic Choice. Gambit Pileup occurs if the other side of the conflict had a Xanatos Gambit in play to account for both possibilities but not this one. And if the coin was a metafictional Schrödinger's Gun, the entire plot goes Off the Rails.
- Something is messing with the laws of probability. Weighted coins, supernatural causes, Negative Space Wedgie, etc.
- Done with an omikuji (fortune) to settle a bet in Tenjho Tenge between Maya and Mitsuomi. The call was "above average luck", he won; "below average luck", Maya won. They never agreed what would happen if they drew "average luck". Also, Maya sniped the fortune before Mitsuomi could open it, so they never settled the bet anyway.
- In No Game No Life, Sora invokes this during "the world's most brutal coin toss" between him and Miko of the Warbeasts. He uses his foot to slide a floor tile and trap the coin on its edge just as it landed, thereby getting a draw and convincing Miko to agree to a deal where both sides get what they want.
- In Rifle Is Beautiful, during episode 10 of the anime, Izumi attempts to dissuade Hikari from buying a 11500-yen Jacket with "Heads you buy it, tails you don't" coin toss. The coin lands on its edge.
- In the game Betrayal at House on the Hill, there is an item called the Mystic Coin which, when flipped, has a one-third chance of landing on its edge, causing your character to take physical and mental damage.
- Asterix once had a con-man visit the village pretending to be an oracle that predicts the future. When captured and tested by Romans, they did the simple coin-flip test and the oracle, trying to prove he was not one, declared that it will be neither heads nor tails. The cartoon additionally showed the coin bouncing all over the place to finally land on edge, prompting the oracle to use I Know You Know I Know to try and get off the hook.
- In one of the early Two-Face stories in the Batman comics, Two-Face tosses his coin to decide whether to reform or not. It lands on its edge, caught in the gap in the floor boards. He declares it's now up to fate to decide and puts the coin away in his vest pocket. He is later saved when a policeman tries to shoot him and the bullet deflects off the coin. As the bullet struck the scarred side, Two-Face decides this means he was meant to be a criminal. Talk about nice job breaking it officer.
- In the very first Two-Face story, after Two-Face captured Batman and Robin and released them unharmed because the coin said so, he captured Batman again. Two-Face said that heads he would free Batman, tails he would kill, and Batman asked about the edge, and said he should agree to turn himself in and co-operate with all plastic surgery and psychotherapy needed to become normal. Two-Face agrees, and the coin does land on its edge. Afterward, Batman revealed to Robin that he had switched Two-Face's coin for one Batman had built and loaded himself. (Unfortunately, Two-Face was too interesting a villain to have only one story.)
- In one Spirou and Fantasio story, mobsters kidnap the eponymous duo to aid in their fight against the Triad (because they are Born Lucky while the gang is literally cursed with bad luck), and before the boss goes to talk with them, he asks his right hand man to flip his lucky coin, heads for them agreeing to help, tails for agreeing gladly. It lands in a roof gutter.
- In a Richie Rich single-page story, Reggie Van Dough was about to flip his double-headed coin to determine who would pay for a meal he and Richie shared: (paraphrasing) "If the coin lands on edge, I'll pay for both of our meals!" The coin did indeed land on edge. It turned out that Richie put glue all around the coin's edge.
- In one of many attempts to choose between Betty and Veronica, Archie Andrews flipped a coin. Naturally, it landed on its edge.
- Dilbert once tries to debunk Ratbert's claim of psychic powers with 100 coin flips.
Dilbert: Call it.
Dilbert: ...That is just a coincidence.
Ratbert: I call edge for the next 99 too.
- He then called "inexplicable hovering followed by hen noises".
Dilbert: THAT IS LUCK. LUCK LUCK LUCK LUCK LUCK LUCK LUCK!
- Dilbert once tries to debunk Ratbert's claim of psychic powers with 100 coin flips.
- This happens in the February 12, 1990 Garfield strip.
Garfield: Heads I stay in bed, Tails, I watch TV.
[coin lands on edge]
[cut to Garfield lying in bed... holding the TV above him]
- The King from The Wizard of Id tried to decide how to execute a condemned prisoner (hanging or guillotine) with a coin toss, only to have the coin land on its edge. The prisoner is briefly overjoyed until the King tells Sir Rodney to hang him with the rope on the guillotine.
- In Mafalda, Felipe attempts a decision with the flip of a coin, but it ends on the side
Felipe: The worst part is that this ambiguous ending made me forget what I was trying to decide...
- "What's the Case" by Ann-Kathrin Kniggendorf, written for Galaxy Rangers. A suspect decides to try an rob a store Gooseman and several other armed customers are shopping in. Goose bums a quarter to try and decide how to find the case. "Heads: it's a robbery, tails: a suicide." The coin lodges in the floor.
- In the Welcome to Night Vale fanfic Existence Is the Most Exciting Thing of All, a bunch of characters try to use coin flipping for some minor decision making, but give up when every single one of them lands on the edge.
- Harry Potter and the Natural 20: After having been bitten by an acromantula, Milo is trying to decide whether a potion Professor Snape gave him is truly acromantula venom antidote like he said it was or another poison designed to kill him faster. He flips a coin to decide whether to drink it or not, and it lands on its edge. Ron comments he didn't know that was possible, while Hermione says it's highly improbable. Seeing as Milo is still alive, he chose to drink it offscreen.
- In Hands Across the Table, Fred MacMurray tells Carole Lombard that hell get a job (something he doesn't want) if the coin lands on the edge. Theyre on a moving bus, and it falls onto oncoming traffic. They block up traffic trying to find the coin, and it's found on its edge, because it landed in a crevice of a manhole. Hilarious Hijinks Ensure indeed.
- The governor in Mr. Smith Goes to Washington needs to appoint a senator; he's trying to decide whether to pick the guy the political boss likes or the popular favorite. When the coin lands on edge, propped up by a newspaper, he picks the guy his kids like — who also happens to be the subject of the story in the newspaper.
- Occurs in MouseHunt. The two brothers flip their only coin to decide who gets the sole twin-sized bed in the house they inherited. The coin lands on its edge, and rolls across the floor until it falls into a hole. They slowly turn to look at each other, amazed... cut to them both in bed together.
- In Shaolin Soccer, one of the ex monks states that their chances of winning the soccer tournament are the same as the coin landing on its side. He drops the coin, and it lands in a crack in the sidewalk, on its edge.
- In Truth or Consequences, N.M., the Psycho for Hire played by Kiefer Sutherland, obsessed with the Twilight Zone episode mentioned below, keeps flipping a coin to try to get it to land on its side. During the climax, it finally does right before he's killed.
- In surreal French-Spanish comedy Charlots Go to Spain (a.k.a. Crazy Boys in Spain, a.k.a. Les Charlots font l'Espagne) The Charlots disagree reading the map and can't figure their yacht's position relative to the minefield. They toss a coin to decide where to turn. In spite of the violently jerking ship the coin firmly stands on edge and they decide to drive the yacht straight into the visible mine.
- World War II. It has become obvious that Nazi Germany is losing. Then Hitler hears a rumor that there is a rabbi who can predict the future. He orders the rabbi be brought to him. Then, this dialogue ensues:
Rabbi: You throw a coin. Heads means: The British Empire will win the war. Tails: The Soviet Union will win.
Hitler: And what if the coin lands on its edge?
Rabbi: Oh, then France will win.
Hitler: [throwing a fit] That's all that can happen?!?
Rabbi: Of course not. It could happen that G-D does a miracle and makes the coin stay in the air. Then, Czechoslovakia will win.
- In The Wheel of Time, this happens around Rand all the time, because he's ta'veren. At one point, Mat flips a coin to try to decide if he should follow Rand or not; the coin lands on edge, but then after a minute falls down on the side that says he shouldn't. It's implied that Rand tips it over by channelling. Later on, Mat's luck powers can make dice balance on edge. Which is how he manages to roll two dice and get a sum of one.
- In The Colour of Magic, when Rincewind is demonstrating that there is a high magical field in the area — flipped coins all land on their edge, aside from a few that turn into other things, and one that falls upwards.
- In a variant, trolls (who aren't too bright, at least at room temperatures) have a gambling game where they bet on whether or not a coin will come down at all. Although given how strong trolls are, this may not be as certain as it sounds.
- Then there's Cohen the Barbarian in The Last Hero, who does a variant of this when told by the gods to roll a seven on a six-sided die. He throws it up in the air, cuts it in half, and has the six and one land facing up on the table.
- Subverted in the BattleTech novel Grave Covenant: A battle for possession of a planet is called by a coin toss (long backstory). The defending commander (who is supposed to throw the "battle") calls "Edge" during the toss. It doesn't come up edge, but the defending commander says something along the lines of "can you imagine the glory of my victory if it did?"
- In the Callahan's Crosstime Saloon series by Spider Robinson, the character of the Lucky Duck bends the laws of probability around him. However, it's done in such a reliable way that when he tosses a coin and asks narrator Jake Stonebender to call it in the air, Jake knows the correct answer is "On its edge."
- In that particular incident, the coin stuck in a crack in the rafters. Quoth Jake: "I'm still right." (or something to that effect).
- And who can forget the tower of five coins...each balanced on its edge...on top of each other.
- In the Forgotten Realms universe, a folk story holds that the goddess of bad luck calls a coin toss by the goddess of good luck to decide the fortune of each newborn, and when the coin lands on its edge the "luckless" child makes their own fate. In another version given in the novel Prince of Lies, Cyric claims that when his turn came up he made the coin disappear before they could see the results (though this is unlikely to have been the case).
- Case 1 and 2 are combined in The Way of Shadows by Brent Weeks. Durzo is being blackmailed into a Sadistic Choice, and is flipping a coin about it: Head he wins, tails I lose. Durzo's friend Kylar wants to cheer him up, and uses some magic to make the coin land on edge. Kylar tells Durzo that there is always a third option, but Durzo is not convinced.
- In an episode of Malcolm in the Middle, Malcolm is driving himself nuts trying to decide whether to get rid of a store display that his mother considers racist but the store owner does not, so he tries to be impartial and dispassionate about it by flipping a coin. Sure enough, the coin lands on its edge. He then turns to the camera looking panicked, but the scene ends before we can see his head exploding.
- Scrubs: JD and Kim flip a coin to decide on keeping their baby. It lands on its side so it remains undecided for the time being.
- The Twilight Zone (1959): In "A Penny for Your Thoughts", when Hector B. Poole pays for a newspaper, the coin lands on its edge and he gains the power to read minds. In the final scene, Hector accidentally knocks over the first coin with a second one and thereby loses his new ability.
- Jimmy James of NewsRadio once tried to pick the new news director this way, between Dave and Lisa. The first time, it landed on its edge. The second time, he flips it into the air... and just stares straight up into the air saying "now that's something spooky"
- A variant occurs in Friends when Chandler, while Monica is on a lucky streak in a game of craps, declares that if her next dice toss is another hard 8 (two fours) again, he and Monica will get married today in Las Vegas. She throws the dice... and one of them rolls off the table. They find it wedged against the table leg, balanced on one corner with two of its faces facing partly up: one of which is the second 4 that they need. Monica tells Chandler that he can decide the result of the dice, and Chandler says that it's a 4.
- In the Charmed episode "From Fear to Eternity", Phoebe flips a coin to decide if she should cover for her boss's affair. The coin lands on its edge and Phoebe remarks, "Oh, that helped a lot".
- An episode of Hannah Montana where Miley is trying to decide which friend she sides with over a stupid argument. She then lampshades this by saying "Oh come on!"
- This result came up in The Peter Serafinowicz Show's Who Wants to Be a Millionaire? knockoff "Heads Or Tails".
- In the "Blitzgiving" episode of How I Met Your Mother, Barney inherits the "Blitz" curse which makes awesome things happen just as he's not there to see it. He leaves the room, and the previous Blitz flips a coin and it lands on its edge. It falls over just as Barney comes back.
- In the Community season 4 finale, a die tossed lands in a crack on a table on its edge, opening a portal from the darkest timeline.
- One of the methods used on Fringe to determine if there is a hole in the universe. Said holes cause the laws of probability to deteriorate, so when they toss a coin ten times (offscreen) and get edges each time, they know there's something fishy going on.
- Game of Thrones: a recurring metaphor through the series is "When a Targaryen is born, the Gods flip a coin." Due to centuries of inbreeding and dealing with otherworldly magic, there is a strong current of hereditary insanity that runs through the Targaryen bloodline. Normally there's no middle ground: a Targaryen ruler is either great or terrible, a just king or a monstrous tyrant. And then Daenerys was born. When the Gods tossed her coin, it landed on its edge. She was both great and terrible, just and monstrous, in equal measure, at the exact same time. And it would only take one final push to knock her coin over to one side or the other. When that push finally came, it landed on tails, and Dany went full Mad Queen and burned King's Landing to the ground.
- In BattleTech's "Twilight of the Clans" story arc, this is both defied and invoked. Clan Nova Cat made deals with the Draconis Combine, but to make their 'losses' look realistic while causing the minimum amount of actual losses, a series of show trials were performed between DCMS and Nova Cat forces. One such trial was down to a coin flip. The Star Colonel in charge calls 'edge', which of course, doesn't happen. When the DCMS commander asks why the Star Colonel made such an impossible call, the Star Colonel replies, "Can you imagine the glory of my victory if I had won?"
- Downplayed and Justified in many wargames which rely on a 6-sided dice. Rolling a handful of dice on a table filled up with models and terrain pieces means that once in a while a die is going to get land on something at an angle and you won't have a clear indicator of which number faces "up". In most cases, the rules advise you to simply reroll these dice.
- The coin landing on its edge is a recurring metaphor for fate in the Legacy of Kain series; it represents Kain's Sadistic Choice in the first game, Blood Omen, to either kill himself and thus doom the vampire race to extinction, or else watch the Pillars of Nosgoth that govern the land's health lower the world into decay as they're unable to be restored while he lives. Given that the Sealed Evil in a Can the Pillars are keeping trapped will be released if either the vampires die out or the Pillars are destroyed, Kain aptly states, "either way, the game is rigged." The "edge", in this case, is the hope that Raziel will realize he possesses true free will and use it to break the Stable Time Loops of the series and throw the timeline into chaos, and hopefully once the dust settles the two of them will be able to Take a Third Option and find a way to get the good bits of both choices. And by the end of the series, they (apparently) succeed.
- CHARNAME from Baldur's Gate is described as a coin on the edge by a seer, based on an in-universe story: at the birth of every person, the goddesses of good and bad luck flip a coin, the sides deciding which goddess' influence will dominate that person's life. If it lands on the edge, neither goddess has a claim and the person is truly free to forge their own path, for good or ill.
- In Poker Night 2, robot character Claptrap occasionally flips a virtual coin to decide what to do. "YAUGH! How does a virtual coin land on its side?!"
- This can happen in Tabletop Simulator, a game that is to tabletop games what Surgeon Simulator 2013 is to actual surgery.
- Freefall, comic 1803, has a peculiar variant. Florence flips a coin to decide whether to help Sam or the police officer who's chasing him. Sam steals the coin before it lands, so she decides to help neither.
- In Check, Please!, when Dex and Nursey are arguing about which one of them should get dibs on Lardo's room, Bitty proposes that they resolve it with a coin flip. The coin winds up getting stuck upright in a crack on the floor and Lardo and Bitty take it as a sign that both of them should share the room, much to Dex's horror.
- In Let's Play Furious Mario - Episode 1 by ProtonJon, he decided to choose which path he would take by flipping a Game Boy Advance cartridge. It landed on its corner.
- Something similar happened to Chuggaaconroy in this episode of Pikmin 2, when deciding which dungeon to enter. It got stuck vertically in the side of his chair.
- Explicitly said never to happen to an SCP Foundation artifact, SCP-1289.
- Also, there is subject SCP-2599, a girl who can fulfill any request, but never fulfills it completely. When ordered to flip a coin so that it lands on heads, it landed on the edge 24 times in a row.
- Uncyclopedia has a template that simulates a coin flip. Digging into the code reveals a 1/2019 chance of landing on "edge", along with a chance of getting "down the drain".
- One episode of Batman: The Animated Series has Batman switch Two-Face's coin with one that always lands on edge. The main result is not so much an inability to make a decision as the fact that the coin rolls away, and he freaks right the hell out and has to chase after it.
- In an adaptation of Asterix and the Big Fight and Asterix and the Soothsayer, said soothsayer is attempting to prove to a centurion that he really isn't a soothsayer. When pressed to guess the result of a coin toss, he panics and says he bets on "neither". Guess what happens?
- The Simpsons: A creepy school inspector (and Anton Chigurh expy) asks Homer to call a coin toss.
Inspector: Call it — friend-o.
Homer: Heads! I mean tails! I mean, on its side! [the coin lands on its side]Inspector: Well done. Now, let me validate your parking. [dramatically punches a ticket, with the same sound as the cattle-gun]
- Happens in the first episode of Gawayn; the coin gets stuck in a gap in a bridge after being flipped.
- The New Scooby-Doo Movies does this in the debut episode "Ghastly Ghost Town." Shaggy and Scooby are in the amusement park ghost town the Three Stooges run looking for Velma, who has gone missing. Deciding whether or not to enter a decrepit saloon, Shaggy flips a coin (a two-headed one at that). He flips, it lands on its side and rolls off into the saloon and into a coin-operated player piano.
- Birthday card: "Heads, you get gifts; Tails, you get money." (Inside) "That darn thing landed on its edge."
- Hey, man. It happens. According to this article, it happens about 1 in every 6000 nickel tosses. It works better with nickels than quarters; nickels have a flat edge, while most other coins have rounded and ridged edges. They're also thicker than the other coins.
- The English baroque composer Jeremiah Clarke, having resolved to commit suicide, stood by the side of a pond, unable to decide whether he should drown himself in it, or hang himself from a tree by its edge. The coin stuck on its side in the mud. So he shot himself.
- The 1987 League Cup semi-final, held over two legs, led to a tie between Arsenal and Tottenham Hotspur. The rules of the competition at the time required a replay, with a coin toss to decide the venue. The coin was tossed up into the air...and wedged itself, edge first, into the White Hart lane mud. (The coin was re-flipped; Spurs won the toss, Arsenal the replay.)
- There is an anecdote that John von Neumann and some of the boys at RAND needed to set up a three way coin flip, when one of them produced a small, specially milled cylinder shaped so that it was equally probable for the 'coin' to come up heads, tails, or edge. Von Neumann studied the cylinder for a few seconds and announced its proportions.
- The same principle is used to make a five-sided die — a triangular prism shaped to have a 2/5 chance of landing on one of its two triangular "heads or tails" faces and a 3/5 chance of landing on one of its three rectangular "edge" faces, giving each a 1/5 chance.
- The coin tossed for the Colombia-Paraguay group match in Copa América Centenario landed on its edge the first time, to the amusement of the officiating team and the two captains. Paraguay won the re-toss, while Colombia won the match 2-1.
- Matt Parker (of Numberphile fame) has been trying to work out the precise coin thickness to ensure that heads, tails and edge each have a one-in-three chance. More information here.
- YouTuber sirrandalot has done more computer models of three-sided coins and notes that there are more variables in play than Matt Parker's team was assuming. In fact, depending on what the coin is made of, how you're tossing it, and what you're tossing it onto the desired ratio varies a lot. However, if you want a single value D/t=1.855 appears to be it.