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

Step 1 The Middle Block

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.

Comments

[J-Five]

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!!!

[Blue Mullet]

Cool!

[CamillaLuvzMusic]

Thanks! Now, to figure out how to win rock paper scissors every time...

[codongolev]

here you go.

[or_ford98]

wow....

[CamillaLuvzMusic]

aweeeesome! I love the Mario Kart reference xDD

[james4]

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

[Blue Mullet]

Huh? Tell me.

[CamillaLuvzMusic]

I havent yet, I want to though.

[Blue Mullet]

Oh. Well good luck trying.

[Dumchicken]

or you could just do the double win

XIXIX
OIXIO
OIXIO

[rimar2000]

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.

[kelseymh]

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]

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.

[kelseymh]

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]

Thanks for the help =)

[kelseymh]

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. Pepper]

Awesome! I love it!