As you know, tic tac toe is a solved game that end in a tie with optimal play. And it's too short to really get any initiative as the second player, even for children. Going second there is no way to force a win without 2 misplays from the first player. So if you want a "strategy" for player 2, it really comes down to just not losing.
As for going ...
This is a generalized version of @Guvante's answer.
O (player 2) always wins in 4. The diagonals are not necessary to achieve a win.
Examples are included in bold, but this strategy works for all choices made by X.
X places a piece at (a,b): (1,1)
O chooses a row that is not a, and places two pieces in that row, but not in column b: (2,2) and (2,5)
Now, O ...
You could draw a 2D array of 2D boards, like this:
▢▢▢ ▢▢▢ ▢b▢
aaa ▢▢▢ ▢▢▢
▢▢▢ ▢▢▢ ▢▢▢
▢▢▢ ▢▢▢ ▢▢▢
▢▢▢ ▢b▢ ▢▢▢
▢▢▢ ▢▢▢ ▢▢▢
c▢▢ ▢▢▢ ▢▢▢
▢▢▢ ▢c▢ ▢▢▢
▢b▢ ▢▢▢ ▢▢c
You'd probably want a 4x4 array of 4x4 boards, though I used 3s everywhere instead to make the example smaller. The example shows a few of the many winning lines (a-c). If it's not clear what ...
The game you are describing is more similar to Three Men's Morris than to Tic Tac Toe. Unlike Three Men's Morris, the extra movement options under the rules you cite mean the game is likely a draw under optimal play. I'm assuming that this game has something akin to Chess's draw due to Threefold Repition; if not, the optimal result of the game is that you ...
Optimal play on NxN boards where you need N in a row leads to a draw for all N > 2.
Contemporary Combinatorics, by Bela Bollobas has a proof of it. Below is a summary of this. The images below are from this book.
All board sizes 5x5 and up can be proven to be a draw by the second player employing a pairing strategy, namely where the second player plays a ...
This sounds like Cube Fusion, specifically the MINI Cube Fusion version as Jay A pointed out based on the number of components.
From the description:
The game includes a playing board with a 3x3 grid and 12 playing
pieces. Each piece consists of two cubes, each with marbles in the
center - one red, one green. Players take turns placing pieces on the
I have flip-flopped a few times, but think that Player 2 has an unbeatable strategy. The trick is that Player 1 needs an X in each row and each column while Player 2 needs a "box". Four O's that form a rectangle with no X's that share a row or column with said rectangle.
First two O's sharing a row with self and separated by 1 square. Never put below or ...
BGG doesn't have any game with "Spillage" in the title. Looking at the Tic-Tac-Toe entry there is also no game that reimplements Tic-Tac-Toe which is the same as Spillage. There are a number of games which play some sort of meta-game of Tic-Tac-Toe in which there are nine 3x3 games being played and the object is to get 3 in a row on the meta-board. So all in ...
This generalization of Tic-Tac-Toe is called m,n,k-game. (the goal is to get k in a row on a (m,n) board).
Some known bounds: (source wikipedia)
(5,5,4) is a draw.
(6,6,5) is a draw.
(7,7,5) and (8,8,5) are draws.
(15,15,5) is a win.
(9,6,6) and (7,7,6) are both draws via pairings.
When the goal is 9 or larger (k>=9) the second player can force a ...
There are several generalizations to tic-tac-toe. The most natural one (imho), is the m,n,k-game, which is the game of k-in-a-row played on an (m,n) board.
In (n,n,n) games, for n>2, the second player can force a draw. See m,n,k-game for many other results.