To celebrate National Scrabble Day—commemorated on April 13 each year, on the birthday of its inventor, Alfred Mosher Butts—here are a few fun facts about the game and the competitions it has inspired.

1. SCRABBLE WAS INVENTED BY AN ARCHITECT.

In 1933, New York City architect Alfred Mosher Butts created an early version of the game we know as Scrabble. To determine how many tiles there should be and how many points each letter should be worth, he calculated letter frequency on the front page of The New York Times. So, for example, "Q is a letter that occurs least often in English text, so it should be a letter that there is only one tile of, and that tile should be worth 10 points," says John Chew, the co-president of the North American Scrabble Players Association (NASPA).

2. IT WASN'T ALWAYS CALLED SCRABBLE.

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Butts named his game Lexico, then changed the name to Criss-Cross Words. His friend and eventual business partner James Brunot came up with the name Scrabble in the late 1930s.

3. INITIALLY, NO GAME MANUFACTURERS WOULD BUY SCRABBLE.

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Butts made the games himself in his garage with Brunot's help, says Chris Cree, co-president of NASPA. "Around 1957, the president of Macy’s saw a game or became familiar with one and placed a huge order that Brunot and Butts couldn’t really fill," Cree says. "Butts had to sell it to Brunot, who had to sell it to Selchow and Righter, who were the manufacturers of the game when I started playing. And they held it until they sold it to Coleco Industries, which sold it to Hasbro."

4. DESPITE ITS LONG HISTORY, SCRABBLE HASN'T CHANGED MUCH.

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"The previous squares are exactly what they were when I first started off—the same 100 tiles and the same distribution," Cree says. "That’s something pretty neat about the game. It hasn’t changed one iota and it’s still popular."

Still, there are crazy variations that people play, including one called Clabbers. "That’s the anagram of Scrabble," Cree says. "You can play words in any order you want to and play the letters in any order you want to as long as the letters can make an anagram of a word."

5. BUT THE GAME MIGHT NOT STAY THE SAME FOR MUCH LONGER.

"There was some controversy [recently] over whether or not—given how much the nature of the game has changed based on the expansion of its playing lexicon in the 60 years that the game has existed—we should still be playing with the same tile values as they get increasingly out of whack compared to the original statistics on which they were based," Chew says. "To be specific, there was a major change in the strategy in the game when the word qat was introduced, I think in the 1980s, and more recently, when the word qi was introduced. Playing the game before you had either of these words as options, if you got the Q, you were pretty much stuck with it until you got a U. And even then, you weren’t sure you could score a lot with it. So we would think that whoever got the Q on average was going to get 10 or fewer points in their game. Now the Q is a much less negative tile to hold on to, so there are some people who think it should be worth 8 points instead of 10 points."

6. YOU CAN USE THE WORD 'BINGO' WHILE PLAYING.

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When players use all seven of their Scrabble tiles to make a word, it’s called a bingo. Yell it out to confuse your opponent!

7. NASPA USES DIFFERENT TILES FOR COMPETITION.

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"If you reach your hand in a bag of wooden set of tiles, you can kind of feel what doesn’t have anything on it and know it’s a blank," Cree says. "We play with smooth tiles to make sure no one can Braille anything."

8. THERE ARE DIFFERENT WORD LISTS FOR DIFFERENT LEVELS OF COMPETITION.

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If you’re playing at the school level, the competitive level, or the international level, NASPA has different lists. "Those are all sort of inclusively nested so that you just have to learn more words as you get on and on to a higher level," Chew says. "The nature of the vocabulary changes—if you're playing at a school level, you're not allowed to play words that could possibly cause offense, even if used in the most polite situations. If you’re playing at an adult-level, you’re supposed to be able to play any word a well-read college educated person should have seen in print in some way. And then if you want to compete at an international level, you have to memorize things like misprints in Shakespearian manuscripts and Syrian texts, names of various obscure animals and plants from around the world and words in Indian and things like that."

9. THE GAME IS PLAYED COMPETITIVELY IN OTHER LANGUAGES—WHICH CAN MAKE THINGS COMPLICATED.

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Chew says he thinks the game is best played in English, though, for a number of reasons. "Some of the aspects of the board and the rules in terms in the spacing of the bonus tiles and the way you build words is best utilized in English," he says. "For instance, in French, it’s a little bit too easy to make words because most French words they can stick an E or an S at the end of so, every time you make a word, your opponent just sticks more letters and gets more points. It’s kind of frustrating that way; everyone scores more points overall."

German Scrabble players have the opposite problem, Chew says; it’s hard to turn an existing German word into a longer German word, which creates a looser word grid—and led to a debate about whether they should use the standard seven tiles or up it to eight. "There was a substantial body of players who felt that there are relatively few words that are interesting in German that are less than eight letters long," he says. "There’s no point to playing with just seven letters." Eventually, the dispute was resolved, and today, Germans play with seven letters, just like the rest of the world does.

There are also tiles specific to certain countries. "In Spanish, there’s a single tile that has two Ls on it," Chew says. "Or Catalan, which has two Ls with a dot in between it, or Dutch, which has an I and a J on it that look a little bit odd to our eyes." Professional linguists have determined the values of those tiles.

10. NASPA'S RULE BOOK IS 50 PAGES LONG.

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"Basically every rule that you look at is a result of someone coming up with a weird interpretation or weird situation," Chew says. If two games are happening at one table, they try to use different colored tiles so they don’t get mixed up (although that sometimes still happens). Each player has 25 minutes total to play his game, and opponents shouldn’t address each other. And there’s computer adjudication of words, too.

11. THERE HAVE BEEN A FEW SCANDALS.

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Before players start a game, they lay out the 100 tiles—in four groups of 5x5 squares—to make sure all the letters are there. One player, says Cree, allegedly saw the blanks and made sure to pick them out and hide them under his leg. "Various times during the game he would introduce them from underneath his leg to his rack," he says. "He was suspected first year of doing so, and it was reported he drew both blanks in 29 out of 31 games. The next year, people were looking for him and he was caught."

There’s also something Chew referred to as the "strip search incident," which occurred during a world championship. "In the world championship, we get a huge cultural divide between the way the people play Scrabble in different countries," he says. "The rules are slightly different around the world, and definitely the etiquette is different around the world."

In this particular incident, a Thai player was facing off against a British player. It was near the end of the game "to the point where there were few enough tiles in the bag that they were keeping track of all the tiles they didn’t play, all the tiles that were sitting in front of them on their rack, and tried to figure out what tiles were still in play and work out all the possibilities and maximize their score regardless of what tiles were in the bag," Chew says. "And they realized that there was a tile that was missing from the game."

The players assured the officials that they had counted the tiles as they were supposed to, but that this tile was gone. "It’s not unheard of for this to happen," Chew says. "Sometimes people turn the board too energetically or brush up against it and a tile falls off. In this case, whether or not the missing tile was in the bag, or was active in the game, affected the win/loss of the game. It was played in the tournament, so there was a lot riding on it. So the emotions were quite heated because the two players didn’t know each other, and the Thai player didn’t really speak English and couldn’t express himself in English to his opponent. It was a situation where if the tile was not discovered or brought back into play, the Thai player would win and if not, the English player would win."

So someone asked the Thai player to turn out his pockets, which made him very angry; he wanted his opponent to turn out his pockets, too—which the Brit didn’t feel like he should have to do, because there was no advantage for him to hold on to the tile. "Then this escalated to well, maybe it’s not in their pockets, maybe it’s down their pants," Chew says. "Maybe they should be strip searched. Maybe they should be taken to the bathroom and undergo a thorough examination at that point. At which point, the British press got a hold of it and I don’t think they ever reported who ended up winning the tournament, but for several days all the tabloids wanted to talk about the missing G."

The missing tile was later found in the coat pocket of a player who had played in the game before. "What happened was, instead of making four 5x5 squares for the players to verify that there are a 100 tiles, these guys made one 9x11 square,” Cree says. "Which when you just sit down and look at what you think is a square and it’s actually a bit of a rectangle, 9x11, 10x10, you just glance at it, it looks fine."

12. THE MOST VALUABLE TILES DEPEND ON YOUR LEVEL OF PLAY.

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"When you’re at a lower level, you probably want to hang on to higher value tiles because you don’t know enough about board strategy to get double or triple value for the high value tiles," Chew says. "At the lowest level, if you get a blank, all you’re going to score with it is 0. But if you get even to the bottom rung of competitive play, then the blank becomes by far the most important tile to hang on to. It lets you occasionally make the 50 point bonus for playing all of your tiles. In theory, if you’re paying at your best, or if you’re a computer program, then that blank is worth about 25 points to the average future value of your score." S is also a good tile to save, Chew says, and a good combination to keep on your rack is "ER or ERS or as many letters in the word RETINAS as you can hold on to."

13. TONS OF NEW WORDS WERE ADDED TO THE DICTIONARY IN 2014.

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They included geocache, chillax, beatbox, frenemy, hashtag, joypad, mojito, selfie, soju, texter, vodcast, vlog, and yuzu, among others. But the ones that will make the most difference are the two letter words, Cree says, the addition of which "allows words to fit on the board that otherwise wouldn’t have."

The two-letter words added were gi, po, te, and da, which is actually making a comeback—it was in the first edition of the Scrabble dictionary, but Chew had it removed for the second edition. "I’m a little bit relieved and nervous about da coming back into the dictionary," he says. "I got [death threats] for about 10 years after it was removed. I’ve learned that if there’s one thing Scrabble players can really get united on—despite the fact that they disagree about everything else—it’s that they don’t want anyone messing with their words. Add new ones if you want, but don’t take away the old ones. Ever since then, I’ve made sure we don’t delete words except in extremely unusual situations, and we definitely don’t mess with the two letter words."

14. IT'S POSSIBLE TO SCORE 1782 POINTS ON A SINGLE WORD.

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That word is OXYPHENBUTAZONE, and to get the points, it would need to be played across the top of the board, hitting three Triple Word Score squares while making seven crosswords downward.

A version of this story ran in 2014.