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Winning tic-tac-toe strategies

Picture of Winning tic-tac-toe strategies

Everyone loves the simple game of tic-tac-toe, but it seems like a random game. Actually, its not!

It seems that many disputes can be solved by a simple game...

Now you can win the next tic-tac-toe-off by looking at these 4 easy strategies!

**EDIT** Thanks to kelseymh for pointing this out- you can only win if your opponent makes a mistake. If both players make the best move they can, the game will tie

 
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Step 1: The Middle Block

Picture of The Middle Block
Tic-Tac-Toe.jpg
Ok, so there are 8 possible ways to win. Here they are in the pic below...

I also labeled  each block with a number to make reference easier.

Did you notice that exactly half (4) of the combinations use the block 5? Most people, if starting, will take that block. They figure it gives them the best chance of winning, because it has more possibilities than, say, taking block 1, where you only have 3 possible paths.

So, by taking block 1 you theoretically have the best chance. But any path using block 1 is very easy to stop.

Step 4: Strategies 3+4

These next two are basically the same but flipped. They aren't as good as the first two, because you only get two paths.

I reccomend taking blocks 4 and 8 first because it makes your move less obvious. But if you do that, the other player may take 5.
J-Five2 years ago
If you start this is an easy win X in center O in corner, then X in diagonal opposite (i.e. upper left lower right). Then if O goes right next the first O then X blocks it. Now O has 2 choices to block X's places, but only place to go. Now, X wins!!!


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Thanks! Now, to figure out how to win rock paper scissors every time...
wow....
CamillaLuvzMusic (author)  codongolev3 years ago
aweeeesome! I love the Mario Kart reference xDD
i know how to
ok first do a regular round of rock paper scissors then call a break after every round if the opponent was scissors and they where rock they would think you would do paper because you would think to do paper so they would do scissors and then you would do rock and win
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I havent yet, I want to though.
Dumchicken3 years ago
or you could just do the double win

XIXIX
OIXIO
OIXIO
rimar20003 years ago
I do not quite understand, my English is poor. My strategy is, taking the center, place the second piece so as to force the opponent to align the second piece with his first, as if he were about to win. Then I lock him with my third piece, and it has no alternative of winning.
kelseymh3 years ago
This is slightly more compact: http://xkcd.com/832/. You may or may not know that if both players make optimal moves every time, the game will always end in a draw. This was proven long ago.
CamillaLuvzMusic (author)  kelseymh3 years ago
So what you mean is if both players are trying to use the same "winning" strategy, it will end in a draw? I get that now, thanks for the help! I found out that when I told my mom what the move I used was, the next time I tried using it she tried to block that move. Because she tried to block that move, I won by another move.,,this is so crazy.
Yes, if both players make the best move they can, you can prove that the game will end in a draw. Tic-tac-toe is simple enough that you can write down every single possible move (that's what the cartoon shows). Every winning game is due to one player or the other making a mistake.
CamillaLuvzMusic (author)  kelseymh3 years ago
Thanks for the help =)
You're welcome! Tic-tac-toe is a very good problem to learn game theory. It is simple enough that you can work out the solution by hand (the Wikipedia article gives you the basic outline), and you can relate it to much more complicated games and theories.
Dr. Pepper3 years ago
Awesome! I love it!