It's a square board that is made up of nine equal squares (3x3).
One of the squares is empty so you can slide the 8 wooden squares around, within the larger board.
The 8 squares have 9 hollows where you can put balls.
You have to get 4 balls next to each other to form a square. You can thwart your opponent by sliding a wooden square away so the balls are no longer in the right place.
Does anyone know what this game is called? Thank you!