Score more points than your opponent by making 4 or 5 symbols in a row (horizontally, vertically or diagonally) on a 5×5 board.
Extending an existing 4 to a 5 only awards the extension point (+1), not the full +2.
You may not place next to your own last move. All 8 cells around your last move are forbidden for your next turn.
If one player has no valid moves left while the other still does, the other player gets one bonus turn. After that the game ends.
Player with the most points wins. Equal score = tie.