<p><strong>As soon as any player gets 3 in a row, that player wins and the game ends. If the board fills up without that happening, the game ends in a draw.</strong></p>
<p>Here are a few sources that clearly indicate this:</p>
<ul>
<li><a href="https://en.wikipedia.org/wiki/Tic-tac-toe" rel="nofollow noreferrer">Wikipedia</a> (This is not explicitly stated in the rules, but the example is like in the question: X wins, O could also make 3 in a row if they could make another move)</li>
<li><a href="https://mathworld.wolfram.com/Tic-Tac-Toe.html" rel="nofollow noreferrer">Wolfram MathWorld</a></li>
<li><a href="https://www.exploratorium.edu/brain_explorer/tictactoe.html" rel="nofollow noreferrer">The Exploratorium</a></li>
<li><a href="https://www.wikihow.com/Play-Tic-Tac-Toe" rel="nofollow noreferrer">wikiHow</a></li>
<li><a href="https://www.gamesver.com/all-about-tic-tac-toe-purpose-rules-how-to-play-strategy/" rel="nofollow noreferrer">gamesver</a></li>
<li><a href="https://www.rookieroad.com/games-for-kids/tic-tac-toe-basic-rules-for-8613021/" rel="nofollow noreferrer">Rookie Road</a></li>
<li><a href="https://www.quora.com/What-are-the-rules-of-tic-tac-toe" rel="nofollow noreferrer">GamesCrafters</a></li>
<li><a href="https://www.quora.com/What-are-the-rules-of-tic-tac-toe" rel="nofollow noreferrer">Quora</a></li>
</ul>

CC BY-SA 4.0
2023-01-30T22:26:12.243Z
The rules on the wikipedia page cited no source. [I've added your answer as a source](https://xkcd.com/978/).
Stef
CC BY-SA 4.0
2023-01-30T22:41:17.780Z
The rules section of the Wikipedia page does not explicitly have a citation, but the page's citations list includes at least a couple of sources that describe the rules in a way that agrees with the article, including one source I previously linked and once source I just added.
murgatroid99
CC BY-SA 4.0
2023-01-19T17:45:52.980Z
2023-01-30T22:40:17.620Z
2023-01-30T22:40:17.620Z
murgatroid99
<p>Tic Tac Toe is famously a <a href="https://en.wikipedia.org/wiki/Futile_game" rel="nofollow noreferrer">futile game</a>, because when both sides play optimally, it always ends in a draw.</p>
<p>Curiously now, a friend of mine (let's call her Alice) played Tic Tac Toe with another friend (let's call him Bob).</p>
<p>The game went as follows:</p>
<pre><code>X: Bob
O: Alice

Move #1                 Move #2

     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
     |     |                 |     |     

Move #3                 Move #4
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
     |     |                 |     |     

Move #5                 Move #6
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
     |     |                 |     |          
</code></pre>
<p>The problem is:</p>
<ul>
<li>Bob maintains he won, because after move #5, he had three <code>X</code> in a row</li>
<li>Alice maintains it's a draw, because after move #6, both had three <code>X</code> or <code>O</code> in a row</li>
<li>Bob argues that the winner is who gets there first</li>
<li>Alice argues that as the second player she's owed a third turn to have the same number of turns, leading to a draw</li>
</ul>
<p>This became a hot debate during an evening with several other friends, where we discovered that people from different countries remembered different rules from their childhood.</p>
<p>Interestingly, rules online seem inconclusive. It usually says the winner is the one who gets three in a row, but it doesn't clearly specify when the game ends. At least one reference mentioned that the game ends when all nine places of the board are filled.</p>
<p>People of the internet, please fix this issue once and for all.</p>

CC BY-SA 4.0
2023-01-19T17:37:03.147Z
I'm having trouble finding ambiguous rules online. What rules were you looking at?
murgatroid99
CC BY-SA 4.0
2023-01-19T18:09:11.467Z
I do love the concept of saying "tic tac toe has an unfair first player advantage, so we'll fix that by giving all players equal turns! After all that works for plenty of good board games!"
GendoIkari
CC BY-SA 4.0
2023-01-19T19:17:46.030Z
The game (like all games) ends when it is won. (Some games have other ending conditions on top of this, but this one is always true for winnable games)
L. Scott Johnson
CC BY-SA 4.0
2023-01-19T19:19:10.037Z
Please cite any reference that says that tic-tac-toe doesn't end until all nine places are filled, so that the reference can be corrected.
L. Scott Johnson
<tic-tac-toe>
What constitutes the end of a Tic Tac Toe game?
marius
# What constitutes the end of a Tic Tac Toe game?

(Asked by: username_0 on 2023-01-19)

Tic Tac Toe is famously a [futile game](https://en.wikipedia.org/wiki/Futile_game), because when both sides play optimally, it always ends in a draw.

Curiously now, a friend of mine (let's call her Alice) played Tic Tac Toe with another friend (let's call him Bob).

The game went as follows:

```
X: Bob
O: Alice

Move #1                 Move #2

     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
     |     |                 |     |     

Move #3                 Move #4
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  -  |  -  |  -           -  |  -  |  -  
     |     |                 |     |     

Move #5                 Move #6
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  O  |  -           X  |  O  |  -  
_____|_____|_____       _____|_____|_____
     |     |                 |     |     
  X  |  -  |  -           X  |  O  |  -  
     |     |                 |     |          

```

The problem is:

* Bob maintains he won, because after move #5, he had three `X` in a row
* Alice maintains it's a draw, because after move #6, both had three `X` or `O` in a row
* Bob argues that the winner is who gets there first
* Alice argues that as the second player she's owed a third turn to have the same number of turns, leading to a draw

This became a hot debate during an evening with several other friends, where we discovered that people from different countries remembered different rules from their childhood.

Interestingly, rules online seem inconclusive. It usually says the winner is the one who gets three in a row, but it doesn't clearly specify when the game ends. At least one reference mentioned that the game ends when all nine places of the board are filled.

People of the internet, please fix this issue once and for all.

**Tags:** tic-tac-toe

> **Comments:**
> **username_1**: I'm having trouble finding ambiguous rules online. What rules were you looking at?  
> **username_2**: I do love the concept of saying "tic tac toe has an unfair first player advantage, so we'll fix that by giving all players equal turns! After all that works for plenty of good board games!"  
> **username_3**: The game (like all games) ends when it is won. (Some games have other ending conditions on top of this, but this one is always true for winnable games)  
> **username_3**: Please cite any reference that says that tic-tac-toe doesn't end until all nine places are filled, so that the reference can be corrected.  

---

## 1 answers

### Answer by username_1 on 2023-01-19. Score: 2

**As soon as any player gets 3 in a row, that player wins and the game ends. If the board fills up without that happening, the game ends in a draw.**

Here are a few sources that clearly indicate this:

* [Wikipedia](https://en.wikipedia.org/wiki/Tic-tac-toe) (This is not explicitly stated in the rules, but the example is like in the question: X wins, O could also make 3 in a row if they could make another move)
* [Wolfram MathWorld](https://mathworld.wolfram.com/Tic-Tac-Toe.html)
* [The Exploratorium](https://www.exploratorium.edu/brain_explorer/tictactoe.html)
* [wikiHow](https://www.wikihow.com/Play-Tic-Tac-Toe)
* [gamesver](https://www.gamesver.com/all-about-tic-tac-toe-purpose-rules-how-to-play-strategy/)
* [Rookie Road](https://www.rookieroad.com/games-for-kids/tic-tac-toe-basic-rules-for-8613021/)
* [GamesCrafters](https://www.quora.com/What-are-the-rules-of-tic-tac-toe)
* [Quora](https://www.quora.com/What-are-the-rules-of-tic-tac-toe)

> **Comments:**
> **username_4**: The rules on the wikipedia page cited no source. [I've added your answer as a source](https://xkcd.com/978/).  
> **username_1**: The rules section of the Wikipedia page does not explicitly have a citation, but the page's citations list includes at least a couple of sources that describe the rules in a way that agrees with the article, including one source I previously linked and once source I just added.  

---

