Tic - tac - toe - wikipedia Tic - tac - toe `` Tic Tac Toe '' and `` Noughts and crosses '' redirect here. For other uses, see Tic Tac Toe ( disambiguation ) and Noughts and crosses ( disambiguation ). Tic - tac - toe A completed game of Tic - tac - toe Genre ( s ) Paper - and - pencil game Players Setup time Minimal Playing time ~ 1 minute Random chance None Skill ( s ) required Strategy, tactics, observation Synonym ( s ) Noughts and crosses Xs and Os Tic - tac - toe ( also known as noughts and crosses or Xs and Os ) is a paper - and - pencil game for two players, X and O, who take turns marking the spaces in a 3 × 3 grid. The player who succeeds in placing three of their marks in a horizontal, vertical, or diagonal row wins the game. The following example game is won by the first player, X : Players soon discover that the best play from both parties leads to a draw. Hence, tic - tac - toe is most often played by young children. Because of the simplicity of tic - tac - toe, it is often used as a pedagogical tool for teaching the concepts of good sportsmanship and the branch of artificial intelligence that deals with the searching of game trees. It is straightforward to write a computer program to play tic - tac - toe perfectly or to enumerate the 7665 essentially different positions ( the state space complexity ) or the 26,830 possible games up to rotations and reflections ( the game tree complexity ) on this space. The game can be generalized to an m, n, k - game in which two players alternate placing stones of their own color on an m × n board, with the goal of getting k of their own color in a row. Tic - tac - toe is the ( 3, 3, 3 ) - game. Harary 's generalized tic - tac - toe is an even broader generalization of tic - tac - toe. It can also be generalized as a n game. Tic - tac - toe is the game where n equals 3 and d equals 2. If played properly, the game will end in a draw, making tic - tac - toe a futile game. Contents 1 History 2 Combinatorics 3 Strategy 3.1 Further details 4 Variations 5 English names 6 In popular culture 7 See also 8 References 9 External links History Games played on three - in - a-row boards can be traced back to ancient Egypt, where such game boards have been found on roofing tiles dating from around 1300 BCE. An early variation of tic - tac - toe was played in the Roman Empire, around the first century BC. It was called terni lapilli ( three pebbles at a time ) and instead of having any number of pieces, each player only had three, thus they had to move them around to empty spaces to keep playing. The game 's grid markings have been found chalked all over Rome. Another closely related ancient game is Three Men 's Morris which is also played on a simple grid and requires three pieces in a row to finish, and Picaria, a game of the Puebloans. The different names of the game are more recent. The first print reference to `` noughts and crosses '' ( nought being an alternative word for zero ), the British name, appeared in 1858, in an issue of Notes and Queries. The first print reference to a game called `` tick - tack - toe '' occurred in 1884, but referred to `` a children 's game played on a slate, consisting in trying with the eyes shut to bring the pencil down on one of the numbers of a set, the number hit being scored ''. `` Tic - tac - toe '' may also derive from `` tick - tack '', the name of an old version of backgammon first described in 1558. The US renaming of `` noughts and crosses '' as `` tic - tac - toe '' occurred in the 20th century. In 1952, OXO ( or Noughts and Crosses ), developed by British computer scientist Alexander S. Douglas for the EDSAC computer at the University of Cambridge, became one of the first known video games. The computer player could play perfect games of tic - tac - toe against a human opponent. In 1975, tic - tac - toe was also used by MIT students to demonstrate the computational power of Tinkertoy elements. The Tinkertoy computer, made out of ( almost ) only Tinkertoys, is able to play tic - tac - toe perfectly. It is currently on display at the Museum of Science, Boston. Combinatorics When considering only the state of the board, and after taking into account board symmetries ( i.e. rotations and reflections ), there are only 138 terminal board positions. A combinatorics study of the game shows that when `` X '' makes the first move every time, the game is won as follows : 91 distinct positions are won by ( X ) 44 distinct positions are won by ( O ) 3 distinct positions are drawn ( often called a `` cat 's game '' ) Strategy Optimal strategy for player X if starting in a corner. In each grid, the shaded red X denotes the optimal move, and the location of O 's next move gives the next subgrid to examine. Note that only two sequences of moves by O ( both starting with center, top - right, left - mid ) lead to a draw, with the remaining sequences leading to wins from X. Optimal strategy for player O. Player O can only force a win or draw by playing in the centre first. A player can play a perfect game of tic - tac - toe ( to win or at least, draw ) if each time it is his turn to play, he chooses the first available move from the following list, as used in Newell and Simon 's 1972 tic - tac - toe program. Win : If the player has two in a row, they can place a third to get three in a row. Block : If the opponent has two in a row, the player must play the third themselves to block the opponent. Fork : Create an opportunity where the player has two threats to win ( two non-blocked lines of 2 ). Blocking an opponent 's fork : If there is only one possible fork for the opponent, the player should block it. Otherwise, the player should block any forks in any way that simultaneously allows them to create two in a row. Otherwise, the player should create a two in a row to force the opponent into defending, as long as it does n't result in them creating a fork. For example, if `` X '' has two opposite corners and `` O '' has the center, `` O '' must not play a corner in order to win. ( Playing a corner in this scenario creates a fork for `` X '' to win. ) Center : A player marks the center. ( If it is the first move of the game, playing on a corner gives the second player more opportunities to make a mistake and may therefore be the better choice ; however, it makes no difference between perfect players. ) Opposite corner : If the opponent is in the corner, the player plays the opposite corner. Empty corner : The player plays in a corner square. Empty side : The player plays in a middle square on any of the 4 sides. The first player, who shall be designated `` X '', has 3 possible positions to mark during the first turn. Superficially, it might seem that there are 9 possible positions, corresponding to the 9 squares in the grid. However, by rotating the board, we will find that in the first turn, every corner mark is strategically equivalent to every other corner mark. The same is true of every edge ( side middle ) mark. For strategy purposes, there are therefore only three possible first marks : corner, edge, or center. Player X can win or force a draw from any of these starting marks ; however, playing the corner gives the opponent the smallest choice of squares which must be played to avoid losing. This might suggest that the corner is the best opening move for X, however another study shows that if the players are not perfect, an opening move in the center is best for X. The second player, who shall be designated `` O '', must respond to X 's opening mark in such a way as to avoid the forced win. Player O must always respond to a corner opening with a center mark, and to a center opening with a corner mark. An edge opening must be answered either with a center mark, a corner mark next to the X, or an edge mark opposite the X. Any other responses will allow X to force the win. Once the opening is completed, O 's task is to follow the above list of priorities in order to force the draw, or else to gain a win if X makes a weak play. More detailedly, to guarantee a draw, O should adopt the following strategies : If X plays corner opening move, O should take center, and then an edge, forcing X to block in the next move. This will stop any forks from happening. When both X and O are perfect players and X chooses to start by marking a corner, O takes the center, and X takes the corner opposite the original. In that case, O is free to choose any edge as its second move. However, if X is not a perfect player and has played a corner and then an edge, O should not play the opposite edge as its second move, because then X is not forced to block in the next move and can fork. If X plays edge opening move, O should take center or one of the corners adjacent to X, and then follow the above list of priorities, mainly paying attention to block forks. If X plays center opening move, O should take corner, and then follow the above list of priorities, mainly paying attention to block forks. When X plays corner first, and O is not a perfect player, the following may happen : If O responds with a center mark ( best move for them ), a perfect X player will take the corner opposite the original. Then O should play an edge. However, if O plays a corner as its second move, a perfect X player will mark the remaining corner, blocking O 's 3 - in - a-row and making their own fork. If O responds with a corner mark, X is guaranteed to win, by simply taking any of the other two corners and then the last, a fork. ( since when X takes the third corner, O can only take the position between the two X 's. Then X can take the only remaining corner to win ) If O responds with an edge mark, X is guaranteed to win, by taking center, then O can only take the corner opposite the corner which X plays first. Finally, X can take a corner to create a fork and then X will win on the next move. Further details Consider a board with the nine positions numbered as follows : 1 5 6 7 8 9 When X plays 1 as their opening move, then O should take 5. Then X takes 9 ( in this situation, O should not take 3 or 7, O should take 2, 4, 6 or 8 ) : X1 → O5 → X9 → O2 → X8 → O7 → X3 → O6 → X4, this game will be a draw. or 6 ( in this situation, O should not take 4 or 7, O should take 2, 3, 8 or 9. In fact, taking 9 is the best move, since a non-perfect player X may take 4, then O can take 7 to win ). X1 → O5 → X6 → O2 → X8, then O should not take 3, or X can take 7 to win, and O should not take 4, or X can take 9 to win, O should take 7 or 9. X1 → O5 → X6 → O2 → X8 → O7 → X3 → O9 → X4, this game will be a draw. X1 → O5 → X6 → O2 → X8 → O9 → X4 ( 7 ) → O7 ( 4 ) → X3, this game will be a draw. X1 → O5 → X6 → O3 → X7 → O4 → X8 ( 9 ) → O9 ( 8 ) → X2, this game will be a draw. X1 → O5 → X6 → O8 → X2 → O3 → X7 → O4 → X9, this game will be a draw. X1 → O5 → X6 → O9, then X should not take 4, or O can take 7 to win, X should take 2, 3, 7 or 8. X1 → O5 → X6 → O9 → X2 → O3 → X7 → O4 → X8, this game will be a draw. X1 → O5 → X6 → O9 → X3 → O2 → X8 → O4 ( 7 ) → X7 ( 4 ), this game will be a draw. X1 → O5 → X6 → O9 → X7 → O4 → X2 ( 3 ) → O3 ( 2 ) → X8, this game will be a draw. X1 → O5 → X6 → O9 → X8 → O2 ( 3, 4, 7 ) → X4 / 7 ( 4 / 7, 2 / 3, 2 / 3 ) → O7 / 4 ( 7 / 4, 3 / 2, 3 / 2 ) → X3 ( 2, 7, 4 ), this game will be a draw. In both of these situations ( X takes 9 or 6 as second move ), X has a 1 3 ( displaystyle ( \frac ( 1 ) ( 3 ) ) ) property to win. If X is not a perfect player, X may take 2 or 3 as second move. Then this game will be a draw, X can not win. X1 → O5 → X2 → O3 → X7 → O4 → X6 → O8 ( 9 ) → X9 ( 8 ), this game will be a draw. X1 → O5 → X3 → O2 → X8 → O4 ( 6 ) → X6 ( 4 ) → O9 ( 7 ) → X7 ( 9 ), this game will be a draw. If X plays 1 opening move, and O is not a perfect player, the following may happen : Although O takes the only good position ( 5 ) as first move, but O takes a bad position as second move : X1 → O5 → X9 → O3 → X7, then X can take 4 or 8 to win. X1 → O5 → X6 → O4 → X3, then X can take 2 or 9 to win. X1 → O5 → X6 → O7 → X3, then X can take 2 or 9 to win. Although O takes good positions as the first two moves, but O takes a bad position as third move : X1 → O5 → X6 → O2 → X8 → O3 → X7, then X can take 4 or 9 to win. X1 → O5 → X6 → O2 → X8 → O4 → X9, then X can take 3 or 7 to win. O takes a bad position as first move ( except of 5, all other positions are bad ) : X1 → O3 → X7 → O4 → X9, then X can take 5 or 8 to win. X1 → O9 → X3 → O2 → X7, then X can take 4 or 5 to win. X1 → O2 → X5 → O9 → X7, then X can take 3 or 4 to win. X1 → O6 → X5 → O9 → X3, then X can take 2 or 7 to win. Variations Main article : Tic - tac - toe variants Many board games share the element of trying to be the first to get n - in - a-row, including Three Men 's Morris, Nine Men 's Morris, pente, gomoku, Qubic, Connect Four, Quarto, Gobblet, Order and Chaos, Toss Across, and Mojo. Tic - tac - toe is an instance of an m, n, k - game, where two players alternate taking turns on an m × n board until one of them gets k in a row. Harary 's generalized tic - tac - toe is an even broader generalization. Other variations of tic - tac - toe include : 3 - dimensional tic - tac - toe on a 3 × 3 × 3 board. In this game, the first player has an easy win by playing in the centre if 2 people are playing. One can play on a board of 4x4 squares, winning in several ways. Winning can include : 4 in a straight line, 4 in a diagonal line, 4 in a diamond, or 4 to make a square. Another variant, Qubic, is played on a 4 × 4 × 4 board ; it was solved by Oren Patashnik in 1980 ( the first player can force a win ). Higher dimensional variations are also possible. In misère tic - tac - toe, the player wins if the opponent gets n in a row. A 3 × 3 game is a draw. More generally, the first player can draw or win on any board ( of any dimension ) whose side length is odd, by playing first in the central cell and then mirroring the opponent 's moves. In `` wild '' tic - tac - toe, players can choose to place either X or O on each move. Number Scrabble or Pick15 is isomorphic to tic - tac - toe but on the surface appears completely different. Two players in turn say a number between one and nine. A particular number may not be repeated. The game is won by the player who has said three numbers whose sum is 15. If all the numbers are used and no one gets three numbers that add up to 15 then the game is a draw. Plotting these numbers on a 3 × 3 magic square shows that the game exactly corresponds with tic - tac - toe, since three numbers will be arranged in a straight line if and only if they total 15. eat bee less → e air bits lip → i soda book lot → o ↙ s ↓ ↓ ↓ l ↘ Another isomorphic game uses a list of nine carefully chosen words, for instance `` eat '', `` bee '', `` less '', `` air '', `` bits '', `` lip '', `` soda '', `` book '', and `` lot ''. Each player picks one word in turn and to win, a player must select three words with the same letter. The words may be plotted on a tic - tac - toe grid in such a way that a three - in - a-row line wins. Numerical Tic Tac Toe is a variation invented by the mathematician Ronald Graham. The numbers 1 to 9 are used in this game. The first player plays with the odd numbers, the second player plays with the even numbers. All numbers can be used only once. The player who puts down 15 points in a line wins ( sum of 3 numbers ). In the 1970s, there was a two player game made by Tri-ang Toys & Games called Check Lines, in which the board consisted of eleven holes arranged in a geometrical pattern of twelve straight lines each containing three of the holes. Each player had exactly five tokens and played in turn placing one token in any of the holes. The winner was the first player whose tokens were arranged in two lines of three ( which by definition were intersecting lines ). If neither player had won by the tenth turn, subsequent turns consisted of moving one of one 's own tokens to the remaining empty hole, with the constraint that this move could only be from an adjacent hole. Quantum tic tac toe allows players to place a quantum superposition of numbers on the board, i.e. the players ' moves are `` superpositions '' of plays in the original classical game. This variation was invented by Allan Goff of Novatia Labs. English names This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. ( August 2018 ) The game has a number of English names. Tick - tack - toe, tic - tac - toe, tick - tat - toe, or tit - tat - toe ( United States, Canada ) Noughts and crosses or naughts and crosses ( United Kingdom, Republic of Ireland, Australia, New Zealand, South Africa, Zimbabwe, India ) Exy - ozys, xsie - osies ( verbal name only ) ( Northern Ireland ) Xs and Os ( Republic of Ireland, Zimbabwe ) Sometimes, the games tic - tac - toe ( where players keep adding `` pieces '' ) and Three Men 's Morris ( where pieces start to move after a certain number have been placed ) are confused with each other. In popular Culture This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( May 2017 ) Wordsworth alludes to tic - tac - toe in his The Prelude ( 1799 ). In the movie WarGames, a computer learns through a tic - tac - toe analogy that nuclear war is unwinnable. The BBC 's Test Card F image includes a picture of a game. In the updated version, Test Card J, the game 's X indicates the exact center of the screen. George Cooper wrote the words and John Rogers Thomas wrote the music for a song `` Tit, Tac, Toe '' in 1876. The adventure game Sam & Max Save the World features an arcade version called Tic - Tac - Doom, but its artificial intelligence is intentionally poor. Rather than beating the game, the player must lose it in order to progress. Episode 452 of This American Life recounts the true story of a legal defense team that sought to overturn the state of Florida 's decision to execute a mentally ill murderer by eliciting a tic - tac - toe playing chicken as evidence. Arcade games with tic - tac - toe - playing chickens were popular in the mid 1970s ; the animals were trained using operant conditioning. In the 1957 film version of Twelve Angry Men there is a small scene were two jurors are playing the game in order to pass the time. In the Three Stooges short Disorder in the Court, Moe and Larry are seen playing tic - tac - toe in a couple of different scenes. ( One with Curly playing jacks over it. ) Elle King 's debut solo single Ex 's & Oh 's references another name for Tic - Tac - Toe, with a punning allusion to her exes ; and how accumulating former partners who never seem to leave her alone is a pointless, unwinnable exercise. Various game shows have been based on tic - tac - toe and its variants : On Hollywood Squares, nine celebrities filled the cells of the tic - tac - toe grid ; players put symbols on the board by correctly agreeing or disagreeing with a celebrity 's answer to a question. Variations of the show include Storybook Squares and Hip Hop Squares. The British version was Celebrity Squares. Australia had various versions under the names of Celebrity Squares, Personality Squares & All Star Squares. In Tic - Tac - Dough, players put symbols up on the board by answering questions in various categories, which shuffle after each player 's turn. In Beat the Teacher, contestants answer questions to win a turn to influence a tic - tac - toe grid. On The Price Is Right, several national variants feature a pricing game called `` Secret X '', in which players must guess prices of two small prizes to win Xs ( in addition to one free X ) to place on a blank board. They must place the X 's in position to guess the location of the titular `` secret X '' hidden in the center column of the board and form a tic - tac - toe line across or diagonally ( no vertical lines allowed ). There are no Os in this variant of the game. On Minute to Win It, the game Ping Tac Toe has one contestant playing the game with nine water - filled glasses and white and orange ping - pong balls, trying to get three in a row of either color. He must alternate colors after each successful landing and must be careful not to block himself. See also Hales -- Jewett theorem Notakto Pick 15 SOS ( game ) Ultimate tic - tac - toe References Jump up ^ Schaefer, Steve ( 2002 ). `` MathRec Solutions ( Tic - Tac - Toe ) ''. Retrieved 2015 - 09 - 18. Jump up ^ Pham, Duc - Nghia ; Park, Seong - Bae ( 2014 - 11 - 12 ). PRICAI 2014 : Trends in Artificial Intelligence : 13th Pacific Rim International Conference on Artificial Intelligence, PRICAI 2014, Gold Coast, QLD, Australia, December 1 - 5, 2014, Proceedings. Springer. ISBN 9783319135601. Jump up ^ Golomb, Solomon ; Hales, Alfred. `` Hypercube Tic - Tac - Toe '' ( PDF ). Retrieved December 17, 2016. Jump up ^ W., Weisstein, Eric. `` Tic - Tac - Toe ''. mathworld.wolfram.com. Retrieved 2017 - 05 - 12. Jump up ^ Zaslavsky, Claudia ( 1982 ). Tic Tac Toe : And Other Three - In - A Row Games from Ancient Egypt to the Modern Computer. Crowell. ISBN 0 - 690 - 04316 - 3. Jump up ^ https://books.google.co.uk/books?id=N4nmGjq5dWsC&pg=PA153 Jump up ^ `` Tic tac toe Ancient Roman 1st century BCE ''. Sweetooth Design Company. Retrieved 2016 - 12 - 04. Jump up ^ Canisius College -- Morris Games Jump up ^ Notes and Queries, 2nd Series Volume VI 152, Nov. 27 1858. Jump up ^ Oxford English Dictionary entries for `` Noughts and Crosses '', `` Tick - Tack '' and `` Tick - Tack - Toe '', dictionary.oed.com ^ Jump up to : Wolf, Mark J.P. ( 2012 - 08 - 16 ). Encyclopedia of Video Games : The Culture, Technology, and Art of Gaming. Greenwood Publishing Group. pp. 3 -- 7. ISBN 978 - 0 - 313 - 37936 - 9. Jump up ^ Cohen, D.S. ( 2014 - 09 - 20 ). `` OXO aka Noughts and Crosses - The First Video Game ''. About.com. IAC. Archived from the original on 2015 - 12 - 22. Retrieved 2015 - 12 - 18. Jump up ^ `` Tinkertoys and tic - tac - toe ''. Archived from the original on August 24, 2007. Retrieved 2007 - 09 - 27. Jump up ^ Bolon, Thomas ( 2013 - 05 - 21 ). How to never lose at Tic - Tac - Toe. BookCountry. ISBN 9781463001926. Jump up ^ `` Searching for the cat in tic tac toe ''. TimesDaily. Retrieved 2016 - 12 - 19. Jump up ^ Kevin Crowley, Robert S. Siegler ( 1993 ). `` Flexible Strategy Use in Young Children 's Tic - Tac - Toe ''. Cognitive Science. 17 ( 4 ) : 531 -- 561. doi : 10.1016 / 0364 - 0213 ( 93 ) 90003 - Q. Jump up ^ Martin Gardner ( 1988 ). Hexaflexagons and Other Mathematical Diversions. University of Chicago Press. Jump up ^ Kutschera, Ant. `` The best opening move in a game of tic - tac - toe - The Kitchen in the Zoo ''. blog.maxant.co.uk. Retrieved 2018 - 04 - 07. Jump up ^ Oren Patashnik, Qubic : 4 x 4 x 4 Tic - Tac - Toe, Mathematical Magazine 53 ( 1980 ) 202 -- 216. ^ Jump up to : Golomb, Solomon W. ; Hales, Alfred W. ( 2002 ), `` Hypercube tic - tac - toe '', More games of no chance ( Berkeley, CA, 2000 ), Math. Sci. Res. Inst. Publ., 42, Cambridge : Cambridge Univ. Press, pp. 167 -- 182, MR 1973012. Jump up ^ Averbach, Bonnie ; Chein, Orin ( 1980 ), Problem Solving Through Recreational Mathematics, Dover, p. 252, ISBN 9780486131740. Jump up ^ Mendelson, Elliott ( 2016 - 02 - 03 ). Introducing Game Theory and its Applications. CRC Press. ISBN 9781482285871. Jump up ^ `` Puzzles in Education - Wild Tic - Tac - Toe ''. puzzles.com. Retrieved 2016 - 11 - 29. Jump up ^ Epstein, Richard A. ( 2012 - 12 - 28 ). The Theory of Gambling and Statistical Logic. Academic Press. ISBN 9780123978707. ^ Jump up to : Juul, Jesper ( 2011 - 08 - 19 ). Half - Real : Video Games Between Real Rules and Fictional Worlds. MIT Press. ISBN 9780262516518. Jump up ^ Michon, John A. ( 1967 - 01 - 01 ). `` The Game of JAM : An Isomorph of Tic - Tac - Toe ''. The American Journal of Psychology. 80 ( 1 ) : 137 -- 140. doi : 10.2307 / 1420555. JSTOR 1420555. Jump up ^ `` TicTacToe Magic '' ( PDF ). Retrieved December 17, 2016. Jump up ^ Math !, Oh Boy I. Get To Do ( 2015 - 05 - 30 ). `` Oh Boy ! I Get to do Math ! : Tic - Tac - Toe as a Magic Square ''. Oh Boy ! I Get to do Math !. Retrieved 2016 - 12 - 17. Jump up ^ Schumer, Peter D. ( 2004 ), Mathematical Journeys, John Wiley & Sons, pp. 71 -- 72, ISBN 9780471220664. Jump up ^ Check Lines, BoardGameGeek, retrieved 2013 - 09 - 13. Jump up ^ Goff, Allan ( November 2006 ). `` Quantum tic - tac - toe : A teaching metaphor for superposition in quantum mechanics ''. American Journal of Physics. College Park, MD : American Association of Physics Teachers. 74 ( 11 ) : 962 -- 973. doi : 10.1119 / 1.2213635. ISSN 0002 - 9505. Jump up ^ `` 452 : Poultry Slam 2011 ''. This American Life. Retrieved 28 May 2016. Jump up ^ Trillin, Calvin ( 1999 - 02 - 01 ). `` The Chicken Vanishes ''. The New Yorker. External links The dictionary definition of tic - tac - toe at Wiktionary Media related to Tic Tac Toe at Wikimedia Commons Tic - Tac - Toe at Wolfram 's MathWorld Discussion about the term `` cat 's game '' for a drawn game of tic - tac - toe Tic - Tac - Toe Tic - Tac - Toe variants 3D tic - tac - toe Gomoku Notakto Number Scrabble Order and Chaos Pente Quantum tic - tac - toe Renju SOS Treblecross Ultimate tic - tac - toe Wild tic - tac - toe List Related concepts m, n, k - game n game Kaplansky 's game Harary 's generalized tic - tac - toe Hales -- Jewett theorem Strategy - stealing argument Futile game Paper - and - pencil game Similar games Nine men 's morris Score Four Tic - Stac - Toe Gobblet Quarto Three men 's morris Nine Holes Achi Connect Four Connect6 OXO Toss Across Pentago Topics in game theory Definitions Cooperative game Determinacy Escalation of commitment Extensive - form game First - player and second - player win Game complexity Graphical game Hierarchy of beliefs Information set Normal - form game Preference Sequential game Simultaneous game Simultaneous action selection Solved game Succinct game Equilibrium concepts Nash equilibrium Subgame perfection Mertens - stable equilibrium Bayesian Nash equilibrium Perfect Bayesian equilibrium Trembling hand Proper equilibrium Epsilon - equilibrium Correlated equilibrium Sequential equilibrium Quasi-perfect equilibrium Evolutionarily stable strategy Risk dominance Core Shapley value Pareto efficiency Gibbs equilibrium Quantal response equilibrium Self - confirming equilibrium Strong Nash equilibrium Markov perfect equilibrium Strategies Dominant strategies Pure strategy Mixed strategy Strategy - stealing argument Tit for tat Grim trigger Collusion Backward induction Forward induction Markov strategy Classes of games Symmetric game Perfect information Repeated game Signaling game Screening game Cheap talk Zero - sum game Mechanism design Bargaining problem Stochastic game n - player game Large Poisson game Nontransitive game Global game Strictly determined game Potential game Games Chess Infinite chess Checkers Tic - tac - toe Prisoner 's dilemma Optional prisoner 's dilemma Traveler 's dilemma Coordination game Chicken Centipede game Volunteer 's dilemma Dollar auction Battle of the sexes Stag hunt Matching pennies Ultimatum game Rock -- paper -- scissors Pirate game Dictator game Public goods game Blotto game War of attrition El Farol Bar problem Fair division Fair cake - cutting Cournot game Deadlock Diner 's dilemma Guess 2 / 3 of the average Kuhn poker Nash bargaining game Prisoners and hats puzzle Trust game Princess and Monster game Rendezvous problem Theorems Arrow 's impossibility theorem Aumann 's agreement theorem Folk theorem Minimax theorem Nash 's theorem Purification theorem Revelation principle Zermelo 's theorem Key figures Albert W. Tucker Amos Tversky Ariel Rubinstein Claude Shannon Daniel Kahneman David K. Levine David M. Kreps Donald B. Gillies Drew Fudenberg Eric Maskin Harold W. Kuhn Herbert Simon Hervé Moulin Jean Tirole Jean - François Mertens Jennifer Tour Chayes John Harsanyi John Maynard Smith Antoine Augustin Cournot John Nash John von Neumann Kenneth Arrow Kenneth Binmore Leonid Hurwicz Lloyd Shapley Melvin Dresher Merrill M. Flood Olga Bondareva Oskar Morgenstern Paul Milgrom Peyton Young Reinhard Selten Robert Axelrod Robert Aumann Robert B. Wilson Roger Myerson Samuel Bowles Suzanne Scotchmer Thomas Schelling William Vickrey See also All - pay auction Alpha -- beta pruning Bertrand paradox Bounded rationality Combinatorial game theory Confrontation analysis Coopetition First - move advantage in chess Game mechanics Glossary of game theory List of game theorists List of games in game theory No - win situation Solving chess Topological game Tragedy of the commons Tyranny of small decisions Retrieved from `` https://en.wikipedia.org/w/index.php?title=Tic-tac-toe&oldid=866101388 '' Categories : Tic - tac - toe Abstract strategy games Positional games Paper - and - pencil games Solved games Hidden categories : Pages using deprecated image syntax Articles needing additional references from August 2018 All articles needing additional references Articles needing additional references from May 2017 Talk Contents About Wikipedia Беларуская Беларуская ( тарашкевіца ) ‎ Català Čeština Dansk Deutsch Español Esperanto Euskara فارسی Français Galego 한국어 Hrvatski Italiano עברית Latina Lëtzebuergesch Lietuvių Magyar Bahasa Melayu Nederlands 日本 語 Norsk ଓଡ଼ିଆ Polski Português Română Русский Seeltersk Slovenčina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் ไทย Українська Tiếng Việt 粵語 中文 33 more Edit links This page was last edited on 28 October 2018, at 07 : 46 ( UTC ). 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Question: what is it called when no one wins at tic tac toe
Answer: cat's game