Copyright (c) 1982 Ravensburger
This game is played on a 3x3 square board with the following setup:
There are three white and three black stones off board.
If it was White's turn, he could win by moving the top white stone at a3 into c3, making a diagonal 3 in-a-row.
If it was Black's turn, he could win by sliding the stacks at a2 and b2 into the right (i.e., a2 would slide to b2, and b2 to c2), making a horizontal 3 in-a-row.