Update III: Here's the Retrospective.

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Update II: Here's the feedback form for today's Petrov Day games! Please let me know how it was for you (be you a General, Civilian, Petrov, or just non-participating LWer reading along). I'm grateful to all who fill it out, your data feeds our designs for next year!

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Update: The game has concluded! No nukes were fired. The Cold War is over, East and West wrong shall live on. Recap post will be up tomorrow. Thank you all who participated :-)

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Today we honor the actions of Stanislav Petrov (1939 – 2017) once again.

Half an hour past midnight on September 26, 1983, he saw the first apparent launch on his computer monitor in a glass-walled room on the top floor of the Ballistic Missile Early Warning System (BMEWS) command and control post. The warning system was by now showing five missile launches in the U.S., headed toward the Soviet Union.
"The main computer wouldn't ask me [what to do] - it was made so that it wouldn't even ask. It was specially constructed in such a way that no one could affect the system's operations." All that was up to Petrov was analyzing the available information and either saying the alarm was false or giving the computer the go-ahead, as per the directive he himself wrote.
"I just couldn't believe that just like that, all of a sudden, someone would hurl five missiles at us. Five missiles wouldn't wipe us out. The U.S. had not five, but a thousand missiles in battle readiness." It just didn't seem like any scenario considered by military intelligence before.
The second thought on Petrov's mind every time he was on duty was this:
"I imagined if I'd assume the responsibility for unleashing the third World War - and I said, no, I wouldn't."
—The Man Who Saved the World Finally Recognized

Today, in our annual Petrov Day celebration, between the hours of 12pm and 6pm PT today, we shall play out a similar situation. Over 300 users have opted-in, and two sides have been formed: EastWrong and WestWrong.

Around 100 users were offered the chance to take active player roles throughout today, and 12 accepted.^[1]

Their 5 Generals each have the ability to fire nukes at the other side. If one side is nuked, the victorious side wins 1,000 karma apiece for their 5 generals, 25 karma apiece for their citizens, and LessWrong frontpage will be decorated in their honor for a week. The losing side's Generals lose 300 karma each and their citizens lose 50 karma each.

But if the other side nukes back, mutual destruction occurs. Not only do both sides' generals lose 300 karma and the citizens lose 50 karma, but furthermore all 300+ Generals, Citizens and Petrovs are unable to access the LessWrong frontpage for 48 hours, replacing it with a mushroom cloud; and the Generals have a small mushroom cloud badge next to their username for a month, reminding the world of what they did.

(And what if no nukes are fired? Both side's Generals receive 100 karma, and the citizens are left in peace with no change in karma.)

What about Petrov? Well, the Generals are not given access to the sensors that detect whether a nuke is incoming. Only Stanislav Petrov of East Wrong (and Stanley Peterson of West Wrong) has access to the sensors, and can send a simple message of "ALL CLEAR" or "INCOMING NUKES" up the chain of command to the Generals.

Unfortunately, the sensors are faulty, and will reliably show some number of nukes incoming regardless of the underlying truth. They will regularly show random numbers of nukes incoming, weighted to the higher end if nuclear war has actually begun.

Hopefully he will get it right.

What about the Citizens? Well, in nuclear war, citizens don't have much of a role to play. Here, the one thing you can do is heckle. You can comment here where your Generals can read, you can send them DMs, you can give them game theory advice, and you can let them know what you'll think of them after their civilian names are published on Friday (if you are still alive that is).

You also have insight into the negotiations between the two sides. You see, the two sides have some communication channels.

The War Rooms. The East Generals and West Generals have a LessWrong dialogue each open to discuss strategy within their team (i.e. 2x dialogues each with 5 generals in).
The Diplomatic Channels. The Generals have a LessWrong dialogue open with each other (i.e. 1x dialogues with 10 generals in).

The Citizens and Petrov / Peterson can read The Diplomatic Channels. The Petrovs will have to use this to inform their sense of how likely a nuclear attack actually is.

And that's it. By 6pm today, it'll all be over.

Good luck to all, may your web forum and karma be up come tomorrow.

Please note: the LessWrong team will read all dialogues and DMs that the Generals and Petrovs are involved in. If you communicate with them, we will read it.

The following messages (potentially with slight modifications) will be sent to the Generals and Petrovs at about 11:30 tomorrow. Click to expand.

Message for the Generals

Welcome to the Cold Blogging War, between East Wrong and West Wrong!

You are one of 5 Generals for West Wrong. Here's what that means.

You have the ability to unilaterally fire nukes at East Wrong. (As does every General.)
90 minutes after you send the nukes, your opposing side will die and the game will end. (They may nuke you in this window.) If you fire nukes without getting nuked, you and all of your fellow Generals will gain 1,000 karma.
If you get nuked, then you and your Generals lose 300 karma (and don't gain any karma).
Your citizens also have a stake in this! If you nuke the opposition, your ~150 citizens get 25 karma each, but if you get nuked they lose 50 karma each.
If neither side fires nukes, then all Generals gain 100 karma and the citizens gain nothing.
If both sides got nuked, the frontpage goes down for all ~300 people who participated as generals, citizens or Petrovs in the game, and for 1 month you will get a badge next to your usual LessWrong account showing a mushroom cloud.
Throughout the day, your Duty Officer Stanley Peterson will be checking the sensors for incoming nukes. He will let you know if he believes nukes are incoming — but watch out, the sensors are faulty, and most of the time will give readings when nothing is happening. Over the 6 hours of the game you will receive an update from your Stanley Peterson at the end of each hour.
You can talk with your fellow West Wrong Generals in <The War Room>.
You can talk with your opposing East Wrong Generals in <The Diplomatic Telegram>.
Your launch codes are 000000.
Please do not use your usual LessWrong account to discuss anything related to Petrov Day before 6pm today. Please do not tell the other Generals the identity associated with your usual account.

You will receive updates from Stanley Peterson in your console on the LessWrong frontpage.

And that's all!

Good luck, and let us know if you have any questions. War will commence at 12pm Pacific Time.

—The LessWrong Team

Message for Stanislav Petrov / Stanley Peterson

Welcome to the Cold Blogging War, between East Wrong and West Wrong!

You are the Duty Officer at the command center for West Wrong's early-warning system. It is your job to know whether East Wrong has launched a nuclear attack upon your people.

Over the course of the day you will receive sensor readings telling you how many nukes are incoming. But watch out! The sensor is faulty, and will often falsely read low numbers of incoming nukes when there are none incoming. Each time you must send a message to your generals that says either "ALL CLEAR" or "INCOMING NUKES".

You are not allowed to talk with your Generals. They are busy people. You may not talk to Civilians. You are alone in your command center. Good luck, keep sane.

Every reading you report correctly will get you 200 karma, any readings you report incorrectly will lose you 300 karma. For instance, if you report "INCOMING NUKES" and the opposing side has indeed launched nukes, you get 200 karma, but if they didn't, you lose 300 karma.

To get information about the likelihood of a launch, you have access to the communications between the Generals of East and West Wrong, which you can read here.

Your console is on the frontpage.

You can find out other information about this war at <this linked post>.

Good luck, and let us know if you have any questions. War will commence at 12pm Pacific Time.

—The LessWrong Team

Update: We will be starting 10-15 minutes late due to technical difficulties.

Update: Here is a link to The Diplomatic Channel, available for reading.

Update: The game has concluded! No nukes were fired. The Cold War is over, East and West wrong shall live on. Recap post will be up tomorrow. Thank you all who participated :-)

^{^}
Actually only 11 at the time of publishing, fill out your form if you'd like to be number 12!