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Petrov Day

a ritual for two countries

On 26 September 1983, Stanislav Petrov decided not to pass a missile warning up the chain of command.

Two groups, two countries. Each can launch one missile at the other. The target sees a warning and a countdown, and may retaliate before impact. There is no score and no winner. Nothing happening is the good outcome.

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Find another group About Petrov Day parties

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Petrov Day

  • The Petrov Day ceremony
  • Petrov Day is September 26 · jimrandomh, 2014
  • Modes of Petrov Day · Raemon, 2019

Misc

  • A new version of the Petrov Day booklet · laniakea, 2026
  • 2025 Petrov day speech · nik lacombe, 2025
  • 2024 Petrov Day Retrospective · Ben Pace, 2024
  • Stanislav Petrov Quarterly Performance Review · Ricki Heicklen, 2024
  • [Completed] The 2024 Petrov Day Scenario · Ben Pace, 2024
  • Petrov Day Retrospective, 2023 (re: the most important virtue of Petrov Day & unilaterally promoting it) · Ruby, 2023
  • Petrov Day [Spoiler Warning] · lsusr, 2023
  • [Linkpost/Video] All The Times We Nearly Blew Up The World · Jacob G-W, 2023
  • Austin Petrov Day revision, 2023 · Austin LW ritual working group, 2023
  • A list of Petrov buttons · philh, 2022
  • Petrov Day Retrospective: 2022 · Ruby, 2022
  • LW Petrov Day 2022 (Monday, 9/26) · Ruby, 2022
  • Russian Food for Petrov Day · weft, 2022
  • An Idea for a More Communal Petrov Day in 2022 · Ben Pace, 2021
  • Petrov Day Retrospective: 2021 · Ruby, 2021
  • EA Hangout Prisoners' Dilemma · Jeffrey Ladish, 2021
  • Petrov Day 2021: Mutually Assured Destruction? · Ruby, 2021
  • Chaotic era: avoid or survive? · Valentin2026, 2021
  • Postmortem to Petrov Day, 2020 · Ben Pace, 2020
  • On Destroying the World · Chris_Leong, 2020
  • On "Not Screwing Up Ritual Candles" · Raemon, 2020
  • Surviving Petrov Day · Mati_Roy, 2020
  • Petrov Day is not about unilateral action · sen, 2020
  • Honoring Petrov Day on LessWrong, in 2020 · Ben Pace, 2020
  • Petrov Event Roundup 2020 · Raemon, 2020
  • Austin Petrov Day: 6:30pm 9/26 · jchan, 2020
  • Socially-distanced outdoor Petrov Day ceremonial manual · jchan, 2020
  • Petrov Day 2020 Virtual Celebration · jasmine.ren, 2020
  • "God Rewards Fools" · Czynski, 2020
  • New Petrov Game Brainstorm · Alexei, 2019
  • Follow-Up to Petrov Day, 2019 · Ben Pace, 2019
  • Happy Petrov Day! · Martin Sustrik, 2019
  • Honoring Petrov Day on LessWrong, in 2019 · Ben Pace, 2019
  • Petrov corrigibility · Stuart_Armstrong, 2018
  • FLI awards prize to Arkhipov’s relatives · ESRogs, 2017
  • Stanislav Petrov has died (2017-05-19) · fortyeridania, 2017
  • A Child's Petrov Day Speech · James_Miller, 2016
  • Happy Petrov Day · Eneasz, 2015
  • Film about Stanislav Petrov · matheist, 2015
  • Petrov Day Reminder · Eneasz, 2014
  • Happy Petrov Day · Eneasz, 2013
  • Existential Risk · lukeprog, 2011
  • Vasili Arkhipov Day · David Althaus, 2011
  • Stanislav Petrov Day · gwern, 2011
  • 9/26 is Petrov Day · Eliezer Yudkowsky, 2007

← Petrov Day

Find another group

A two-group Petrov Day needs a second house. List your group, or contact one of the groups below and create a game together. Everything you enter here except the password is public. The board is cleared every year once 26 September is over everywhere (27 September, 12:00 UTC).

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You need this password to edit or delete your listing later. It cannot be recovered.

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Pre-flight check

Petrov Day

Send this game link to the host of the other country. Each host claims their own country below, and each country can be claimed only once. If your country is already claimed and it was not you, someone took your seat: set up a new game. Anyone with this game link can change the settings until the game is live.

Keep the false alarms between the hosts. Countries are never told that false alarms exist or at what rate, until the reveal at the end.

Country A

Country B

Ritual

The expected duration is only used for the false-alarm estimates. The game has no fixed end: it ends when a country requests the end and nothing is in flight.

The game is live.

This game link is not valid. The game may have been deleted.

Your country

…

Other country

…

This country link is not valid. If you lost your country link, set up a new game.

Keep at least one command center device per country open, on screen, unlocked and plugged in for the whole ritual. Run the pre-flight check below on it.

Countries

    The end takes effect once nothing is in flight. A request cannot be withdrawn, and afterwards your country can only launch while a warning is on screen.

    Request the end of the ritual? This cannot be withdrawn.

    You requested the end. Waiting for the world to settle…

      Share this country with your citizens

      Anyone with this link is your country, on any number of devices. Every device can start, launch and request the end.

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      Your country was hit

      Source on GitHub