Game combinations of tic-tac-toe [closed]

How many combinations are possible in the game tic-tac-toe (Noughts and crosses)?

So for example a game which looked like: (with positions 1-9)

A1   --   B1

A2   --   B2

A3   --   --

[1][3][4][6][7] would be one combination


This information is taken from this website.

A naive estimate would be $9!=362\,880$, since there are $9$ possible first moves, $8$ for the second move, etc. This does not take into account games which finish in less than $9$ moves.

  • Ending on the $5^\text{th}$ move: $1\,440$ possibilities
  • Ending on the $6^\text{th}$ move: $5\,328$ possibilities
  • Ending on the $7^\text{th}$ move: $47\,952$ possibilities
  • Ending on the $8^\text{th}$ move: $72\,576$ possibilities
  • Ending on the $9^\text{th}$ move: $127\,872$ possibilities

This gives a total of $255168$ possible games. This calculation doesn't take into account symmetry in the game.


I will say that the board combinations are 3^9, which is 19683 possibilities, and 2032 winning positions. The answer of 9! is related to how many ways we have to fell all the positions, rather than the possible combinations.

I have answered this question already in another post, please see the next link: https://stackoverflow.com/a/54035004/5117217

Cheers!