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.

TURN -  On each turn, each player must do one of the following options.
Drop a friendly stone on a stack of size 1.
Slide a line of one or two stacks into the direction of the empty cell.
Move a friendly top stone of a stack of size 2 into the top of any stack of size 1. 
GOAL - A player wins by making a (orthogonal or diagonal) 3 in-a-row with his stones (i.e., a line of three stacks with friendly stones at the top).
An example

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.