Why does “break a leg” translate to good luck and where did the phrase come from?
Some more thoughts here.
Before going onstage, I urge all members of my opera company to “snap a vocal cord.”
"Good luck is bad,
bad luck is good.
Say ‘Break a Leg’,
and it’s understood.
Funny you should mention that. Before going onto a performance, magicians say, “Break a thread.” to each other.
There also seems to be a lesser known prohibition against saying ‘MacBeth’. I’ve curious circumlocutions referring to ‘The Scottish Play’. Also complicated routines to shake off the bad luck, should it be uttered, featuring rhymes and slapping.
Perhaps this was just comedic exaggeration of Thespian Superstitions?
It was featured prominently in a Black Adder episode, but I’ve seen it elsewhere.
Anyone got the Straight Dope?
You are not supposed to say Macbeth backstage, nor are you supposed to say any lines from Macbeth. To break the curse I was always told you had to say a line from one of the comedies and then turn three times. There is a lot of bad luck associated with the play, possibly because when people think something is bad luck they remember the bad things that happen in the course of a production. One theory though goes something like Shakespeare did his research on the witch’s spells too well.
Another back stage bad luck thing has to do with whistling. You are never supposed to whistle backstage. This one has its basis in historical fact actually. To create all the scenic magic takes alot of rigging. In the old days much of that rigging was taught to stagehands by sailors. You also have to be able to do things like bring scenery up and down fast and in unision with someone else. In the days before headsets the sailor’t trick of the bosun’s whistle was used. If someone whistled backstage and happened to hit the right pitch, it could happen that thousands of pounds of scenery would come plowing towards someone’s head.
This is the reason I always assumed to be correct for “break a leg.” That is, “break” = “bend” while taking your bow. The better you do, the better the crowd responds, the deeper your bow at curtain call should be in appreciation of the audience’s appreciation of you. Similarly, with the Shakespearean bow (one leg straight out front), the deeper the bow, the more it feels like that leg really will break. So “break a leg” is basically “earn the right to bow low.”
I find it strange that the commonly accepted theories outside of the theater about the origin of break a leg are so different from those inside the teatrical community. I don’t know it it is indeed true but the site that Only Mostly Dead posted has the answer that most theater people will give you. I was told it dates back to Elizabethan theater when you had a very stylized deep bow, left leg placed far in front of you (not bent) and right leg “broken” at the knee behind it. You then bend at the waist and bring yourself as close to the ground as possible.
Also, as far as referencing The Scottish Play, I am not personally superstitious but saying MacBeth in a theater is one of the best ways to freak out almost anyone within earshot. The last show I worked on someone accidentaly let the word slip and about 10 people stopped what they were doing and made the poor girl jump through all kinds of hoops to reverse the cure. The problem is that there is very little agreement on counter curse messures, so she had to do a half dozen things before everyone was satisfied.
There are tons of theories about why uttering the word MacBeth is bad luck, my favorite being that Shakespeare used a real witch’s spell in the opening of the play (double double toil and trouble etc) and that mentioning the play brings down the wrath of the spirits.
Another favorite theory is that in the 1800’s MacBeth was only perfromed by theaters that were about to go out of business in a last ditch effort to bring patrons to the theater. This is because MacBeth lends itself to a lot of blood and spectical and is almost certain to bring in crowds. But because the theaters were generally failing anyway MacBeth was frequently the last show performed before the theater went under. So MacBeth became associated with the theater failing.
Theater has the best folklore 
Yep. Forgot to say that where I had heard the explanation was during my high school days, when I was very much into theater, and was a leading member (either performing onstage or working tech when the acting bug was dormant) in my high school’s group. It is, as you said, probably an “in” thing to use that explanation.
And no theater is worth beans without its very own ghost.