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Ultimate Tic Tac Toe

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Re: Ultimate Tic Tac Toe

#61

Post by shardling »

A weird version of tic-tac-toe my friends and I came up with years ago: you play without a board. Any move is valid so long as you could superimpose a standard tic-tac-toe grid over the results. (You assume the marks are at the center of their respective squares; you allow the board to be at any scale or angle, but you can't skew it.)

The first two moves have no constraint, so you can just start with an X and O already on the board. And after a few moves there might be only one implied board possible, after which it reduces to the normal game. But I always thought it was an interesting twist.

Re: Ultimate Tic Tac Toe

#62

Post by seri »

bierik wrote: post #51
nawitus wrote: post #39

Does anyone else play the 'infinite board' tic-tac-toe which requires you to get five in a row? It's what I used to play as a student, and it's pretty well-known at least where I live. Nobody bothers with the 3x3 version, but the five in a row version is pretty exciting and requires plenty of strategy and thinking ahead.

I think this is called "Gomoku" (just on a quasi-infinite board): http://en.wikipedia.org/wiki/Gomoku I used to play this a lot when I was still at the university

Yup, Gomoku is a much more difficult game than it looks. Indeed, the game is challenging enough that there is a world championship every odd year. You can find the games from the last world championship here: http://renju.net/media/games.php?gameid=45016

I am amazed by the fact that Gomoku can be so hard to master with rules so simple you can explain to a five year old. And unlike Chess where there are a hundred year of theories to learn from before you can get going, Gomoku is still new. After a few weeks studying the standard surewin openings, you can expect to see things in a very different light and the game will get much more interesting.

Perhaps Gomoku is best known for programmers as a problem to solve. But it is nowhere near being solved. In fact, the best software are weaker than many top players.

I find Gomoku hits the sweet spot when it comes to my desire to play board games. It doesn't consume much of my time. I am always excited to find those long and obscure wins. I think the game needs more love from programmers like me.

Facebook page: https://www.facebook.com/GomokuWorld Play here: http://www.playok.com/en/gomoku/ Or here: http://fumind.com

Re: Ultimate Tic Tac Toe

#64

Post by homonculus »

3pt14159 wrote: post #36
jbri wrote: post #30

Earlier quoted context omitted.

Instead of filling the center square on the last board, you can fill the corresponding square and then start forcing your opponent to win that board.

Doesn't quite work, since the opponent can chose the centre square which leaves you with a free move, but whatever master square you place your free move in, can no longer be used to force him back into the same master square.

The opponent can't choose the center square because you've already filled them all in the initial phase of the gambit.

Re: Ultimate Tic Tac Toe

#66

Post by danielweber »

opendomain wrote: post #40
quesera wrote: post #23

I think the Orwin gambit can be extended to win the game every time. - Force opponent to fill center miniboard, as he describes. - Force opponent to fill (e.g.) northeast corner in the same way. Opponent now has taken two miniboards, and you have none, but you are one turn away from taking each of the remaining seven. - Pick SW corner of SW corner. You have taken SW corner miniboard. Opponent is forced to play in sam…

The answer is obvious: the next player must play the corresponding board UNLESS it is already won. Thne they can choose which board to go to randomly.

This raises an interesting wrinkle: a sub-board can be won by both X and O, if you can keep on playing after it is won.

Re: Ultimate Tic Tac Toe

#67

Post by Someone »

CJefferson wrote: post #20
k2enemy wrote: post #18

Earlier quoted context omitted.

Zermelo's theorem[1] says "yes," although I don't know which it is (between draw, p1 win, p1 lose). [1] https://en.wikipedia.org/wiki/Zermelo%27s_theorem_%28game_th...

In fact, it can't be a p1 lose, because the extra piece p1 gets can never be a disadvantage (you can prove this more carefully). The question is then is it a p1 win, or draw? A similar situation arises in the game 'hex', except in that game there is no draw, so it has to be a p1 win!

"because the extra piece p1 gets can never be a disadvantage (you can prove this more carefully)"

Please do so, as I do not see that this is trivially true. I see two tricky cases:

- your opponent must play on the board where p1 is placed, and that board would have room iff p1 weren't present => Addition of p1 gives him a 'move anywhere' move.

- you must play on the board where p1 is placed, and that board would have room iff p1 weren't present. The normal argument 'move anywhere and assume that that 'anywhere' is where your first move went, and you just played p1' does not help here, as changing the first move may change where your opponent's first move could have gone.

Except from an exhaustive search, I do not see how to prove that you can prevent either case.

Re: Ultimate Tic Tac Toe

#68

Post by danielweber »

speeder wrote: post #42
yarekt wrote: post #34

http://graffitiwall.co.uk/ultimatetictactoe My quick implementation of this game Edit: For anyone who arrived 10 seconds after i posted that link, The board resembled the ultimate tic tac toe, and then quickly degraded into a paint fight

Interesting that hackers instead of working or reading HN are very interested in fighting over the board (ie: gray color people try to erase it, pink color try to draw a board, and blue color trying to play the game...)

"Someone keeps stealing my letters" http://www.lunchtimers.com/

Re: Ultimate Tic Tac Toe

#69

Post by lucb1e »

tripzilch wrote: post #59
lucb1e wrote: post #6

Earlier quoted context omitted.

A "small" update? I think this is more like the difference between checkers and chess. But yes, relevant xkcd

> I think this is more like the difference between checkers and chess I'm not sure what you mean by this? BTW are you aware that despite it has only one type of stone and simpler rules, checkers is in fact the more complex game, to write an AI for?

I don't know why you're downvoted for asking a question, but what I meant is this: The person I replied to said the admin of XKCD could do a "small" update to his post about tic tac toe. I remarked that this is not a small update, and used checkers and chess as an analogy. Chess is much more complex and harder to learn than checkers, and as you remarked, chess is indeed harder to write an effective AI for. Just like the difference between tic tac toe and ultimate tic tac toe ;)

Edit: I meant chess is harder to write an AI for of course, not checkers. Fixed.

Re: Ultimate Tic Tac Toe

#70

Post by CJefferson »

Someone wrote: post #67
CJefferson wrote: post #20

Earlier quoted context omitted.

In fact, it can't be a p1 lose, because the extra piece p1 gets can never be a disadvantage (you can prove this more carefully). The question is then is it a p1 win, or draw? A similar situation arises in the game 'hex', except in that game there is no draw, so it has to be a p1 win!

"because the extra piece p1 gets can never be a disadvantage (you can prove this more carefully)" Please do so, as I do not see that this is trivially true. I see two tricky cases: - your opponent must play on the board where p1 is placed, and that board would have room iff p1 weren't present => Addition of p1 gives him a 'move anywhere' move. - you must play on the board where p1 is placed, and that board would have…

Yes, you are right.

Actually, the fact you force your opponent isn't the problem (I don't think) but the fact that the presence of that piece might later give p2 a free move, where previously they wouldn't means it doesn't work.

Sorry, that's what I get for thinking I didn't need to figure out all the details carefully!

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