Your move's position within a mini-board determines which mini-board your opponent must play in. Sent to a finished board? Play anywhere. Three mini-board wins in a row on the meta board wins the game.
The board is a 3×3 grid of nine smaller tic-tac-toe boards. You play X, the AI plays O. X moves first and can pick any cell on the board.
After your move, the position you played (top-left, center, bottom-right, etc.) tells your opponent which mini-board they must play in next. If that mini-board is already won or full, the opponent gets a free choice anywhere on the board.
Win a mini-board by getting three in a row inside it — that claims the matching cell on the meta board. Win three mini-boards in a row on the meta board to win the game.