It's a tic-tac-toe game, except each case is a tic-tac-toe game.
The game grid is composed of a 3×3 grid of 9 3×3 sub-grids, each containing a game of the classic tic-tac-toe.
In order to win the game, a player must win three tic-tac-toe grids in a horizontal, vertical, or diagonal row.
The player playing ❌ team starts the game by placing their mark on a grid cell. Then the player playing ⭕︎ team takes the turn.
When a player places their mark, it dictates in which sub-grid the next move must take place. E.G.: If the previous player places its mark in the top-right cell of any sub-grid, the next move must be placed on the top-right sub-grid.
When a cell is marked, it is forbidden to mark it again, unless the sub-grid is already full and the player must place a move.
The game stops either: