# Cluedo
**Cluedo** is a murder-mystery board game of deduction in which two to six players race to be the first to correctly name a murder suspect, weapon, and room, using elimination reasoning over a deck of cards. It was invented by Anthony E. Pratt, a solicitors' clerk from Birmingham, England, and first produced in the United Kingdom by Waddingtons in 1949.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) The North American edition, licensed the same year to [Parker Brothers](https://www.edgepedia.org/parker-brothers), is sold as **Clue**.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
| Key fact | Detail |
|---|---|
| Designer | Anthony E. Pratt of Birmingham, with his wife Elva; conceived during World War II air-raid blackouts[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) • [3](https://www.history.com/articles/clue-game-origin-wwii) |
| First release | Patented 1947; launched 1949 as Cluedo (Waddingtons, UK) and Clue (Parker Brothers, US), delayed by post-war shortages[3](https://www.history.com/articles/clue-game-origin-wwii) • [2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) |
| Card structure | 21 cards: 6 suspects, 6 weapons, 9 rooms; one of each type hidden in the case file, the remaining 18 dealt to players[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) |
| Solution space | 6 × 6 × 9 = 324 possible solutions before any deduction[4](https://tabletopcalc.com/clue-deduction-strategy.html) |
| Players | 2 to 6, each taking the role of one of the suspects; a player's guilt or innocence does not affect play[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) • [1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) |
| Publication record | In print continuously since 1949, with international versions including a Norwegian edition titled 'Key' (1953)[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) |
| Current owner | Waddingtons' games division was sold to Hasbro in 1994[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) |
## Origin
Pratt worked as a pianist in European hotels between the world wars and enjoyed the murder-mystery party games played there, in which guests roamed a house, crept up on one another in corridors, and fell 'dead' on the floor.[5](https://www.toyhalloffame.org/toys/clue/) • [2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) During the Second World War, the blackout restricted such parties, so he recreated the experience in miniature as a board game he called *Mur!*.[3](https://www.history.com/articles/clue-game-origin-wwii) • [2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
In 1944, Pratt and his wife Elva took the game to Waddingtons in Leeds and presented it to the executive Norman Watson, who accepted it and renamed it Cluedo, possibly as a play on the game [Ludo](https://www.edgepedia.org/ludo), whose name is Latin for 'I play'.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) Pratt patented the game in 1947 and sold it to Waddingtons and its American counterpart Parker Brothers (now owned by Hasbro).[3](https://www.history.com/articles/clue-game-origin-wwii) Post-war material shortages delayed the launch until 1949, when the game appeared simultaneously in both markets.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
## Gameplay
A deck of 21 cards depicts the six suspects, six weapons, and nine rooms. One card of each type is chosen at random and placed unseen into a case-file envelope; these three cards are the solution. The remaining 18 cards are shuffled and dealt clockwise, as evenly as the player count allows.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) In the back-story, Mr. Boddy has been murdered in a room of his mansion, and the object is to deduce the suspect, weapon, and room.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) In the British edition the victim is Dr. Black.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
On each turn a player rolls dice to move around the board, visiting rooms and making suggestions: a named suspect, weapon, and room. Opponents answer in clockwise order; a player holding one or more of the suggested cards must reveal one of them privately to the suggester, and a player with none must say so.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) Each player may make one accusation during the game, checking the case file directly: a correct accusation wins, an incorrect one eliminates the accuser from winning, though the player continues to answer suggestions.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf)
Because every card seen or ruled out removes possibilities, the game is at root an information problem. Before any deduction there are 324 possible solutions; each card a player holds removes a share of that space, and each suggestion and answer updates the probabilities of what remains in the envelope.[4](https://tabletopcalc.com/clue-deduction-strategy.html)
## Deduction and strategy
**What players can deduce.** [Beginners](https://www.edgepedia.org/beginners) typically rely on exhaustive elimination, marking only the cards in their hand and cards they have seen. Experienced players also apply propositional logic to cards they have not seen: if player X asks player Y for cards A, B, or C and Y shows a card, everyone can deduce that Y holds at least one of the three; if Y passes, everyone knows Y holds none of them; and a player whose full hand is known holds none of the remaining cards.[6](https://teaching.bb-ai.net/Student-Projects/papers-slides/Cluedo-Strategy-Kingston-AISB-2017.pdf)
**Measured strategies.** John Kingston of the University of Brighton built a program, based on the movement-free 'Speed Clue' variant, to compare five questioning strategies in three- and six-player games.[6](https://teaching.bb-ai.net/Student-Projects/papers-slides/Cluedo-Strategy-Kingston-AISB-2017.pdf) The results showed that using logic about present and absent cards to guide questioning does improve performance, but not always: there were games in which logical deduction made play worse than random questioning. The best strategy overall was 'Next-not-held', asking about cards known to be absent from the next player's hand in order to search for a possible solution, and the room proved the hardest category to deduce, making room-focused questions valuable.[6](https://teaching.bb-ai.net/Student-Projects/papers-slides/Cluedo-Strategy-Kingston-AISB-2017.pdf)
**Formal reasoning.** Todd W. Neller, a computer scientist at [Gettysburg College](https://www.edgepedia.org/gettysburg-college), and Ziqian Luo modeled Clue knowledge with pseudo-Boolean 'at-least' constraints and estimated card probabilities with a WalkSAT-based sampling algorithm, treating the game as a knowledge game in the sense of van Ditmarsch.[1](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf) The game has also been used as a testbed for language models: in a text-based multi-agent version with six agents drawn from GPT-4o-mini and Gemini-2.5-Flash, the agents achieved only four correct wins across 18 simulated games, indicating difficulty maintaining consistent deductive reasoning over a full game.[7](https://arxiv.org/abs/2603.17169)
## Editions and characters
The game has never been out of print since 1949 and has spawned many international versions.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) The North American Clue edition made small changes: the victim became Mr. Boddy, and the suspect Reverend Green became Mr. Green, reportedly because Parker Brothers' Bob Barton thought the American public would not accept a parson as a murder suspect.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x) A Norwegian edition titled 'Key' was published by N.W. Damm of Oslo in 1953, and a Leeds Centenary Edition of 1993 replaced the suspects with local celebrities such as Barbara Taylor Bradford and [Jilly Cooper](https://www.edgepedia.org/jilly-cooper) and the rooms with Leeds landmarks.[2](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
The cast has changed with the times. In 2016 Hasbro retired Mrs. White after 70 years and introduced Dr. Orchid, a female scientist with a PhD in plant toxicology and the adopted daughter of the mansion's owner; she was the game's first female character with an official profession outside the home.[8](https://time.com/4401819/clue-board-game-dr-orchid-mrs-white/) In January 2023 Hasbro launched a reimagined edition built around the question 'Who killed Boddy Black?', with each suspect given a new character, backstory, and motive, and announced further Clue games and virtual experiences.[9](https://corp.hasbro.com/news-releases/news-release-details/hasbros-classic-clue-board-game-reimagined-thrilling-new) An official digital version by Marmalade Game Studio, released on iOS and Android in 2023, offers both the 2023 cast and a 'Retro Rules Set' restoring the 1949 rulebook and the 2016 characters.[10](https://www.marmaladegamestudio.com/games/cluedo) • [11](https://www.marmaladegamestudio.com/news/fan-favourite-clue-cluedo-suspects-arrive-in-clue-cluedo-mobile-game)
## Related deduction games
Cluedo belongs to a family of deduction board games with different structures. 13 Clues, set in Victorian London, inverts the Cluedo information structure: each player can see the clues held by the others but not their own.[12](https://opinionatedgamers.com/2017/01/25/dale-yu-review-of-13-clues/) Konami's digital game Crimesight reformulates the Cluedo premise, a mansion, six guests, a weapon, and a victim, into a two-player contest between AI avatars of Sherlock and Moriarty.[13](https://as.com/meristation/2022/06/21/analisis/1655799662_649205.html)
## References
1. [Todd W. Neller and Ziqian Luo (2018). Mixed logical and probabilistic reasoning in the game of Clue. ICGA Journal 40, 406–416.](https://cs.gettysburg.edu/~tneller/papers/icgaj18-clue.pdf)
2. [Rebecca Fallas (2016). Waddingtons Cluedo and how 'The Great Detective Game' was made in Leeds. Leeds Museums and Galleries.](https://museumsandgalleries.leeds.gov.uk/blog-waddingtons-cluedo-and-how-the-great-detective-game-was-made-in-leeds-m83x)
3. [The Game Clue Was Born of Boredom During WWII Air-Raid Blackouts. HISTORY.](https://www.history.com/articles/clue-game-origin-wwii)
4. [Clue / Cluedo Deduction Strategy: The Probability Behind Solving the Case. TabletopCalc.](https://tabletopcalc.com/clue-deduction-strategy.html)
5. [Clue. The Strong National Museum of Play.](https://www.toyhalloffame.org/toys/clue/)
6. [John Kingston (2017). Comparing question asking strategies for Cluedo. AISB Symposium on AI & Games, University of Brighton.](https://teaching.bb-ai.net/Student-Projects/papers-slides/Cluedo-Strategy-Kingston-AISB-2017.pdf)
7. [Rebecca Ansell and Autumn Toney-Wails (2026). How Clued up are LLMs? Evaluating Multi-Step Deductive Reasoning in a Text-Based Game Environment. arXiv:2603.17169.](https://arxiv.org/abs/2603.17169)
8. [Meet the New Character in the Classic Board Game Clue. TIME.](https://time.com/4401819/clue-board-game-dr-orchid-mrs-white/)
9. [Hasbro's Classic Clue Board Game Reimagined in Thrilling New Experience. Hasbro, Inc., 4 January 2023.](https://corp.hasbro.com/news-releases/news-release-details/hasbros-classic-clue-board-game-reimagined-thrilling-new)
10. [Official Cluedo Game. Marmalade Game Studio.](https://www.marmaladegamestudio.com/games/cluedo)
11. [Fan-Favourite CLUE/CLUEDO Suspects Arrive in CLUE/CLUEDO Mobile Game. Marmalade Game Studio.](https://www.marmaladegamestudio.com/news/fan-favourite-clue-cluedo-suspects-arrive-in-clue-cluedo-mobile-game)
12. [Dale Yu (2017). Review of 13 Clues. The Opinionated Gamers.](https://opinionatedgamers.com/2017/01/25/dale-yu-review-of-13-clues/)
13. [Crimesight, análisis. MeriStation (AS.com), 21 June 2022.](https://as.com/meristation/2022/06/21/analisis/1655799662_649205.html)
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*Topic: Encyclopedia › Sports, games, and recreation › Board, card, and puzzle games › Board games › Modern designer board games › Deduction and hidden-information board games*
*Initially written Sep 17, 2026 · Reviewed: Oct 21, 2026 · Edited: Oct 15, 2026; Oct 21, 2026; Oct 25, 2026 · Last review: Oct 21, 2026*
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License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license