Copyright (c) 2002 Walter Joris

This game is played on a 5x5 board:

SETUP - One player drops 6 white stones and 6 black stones on empty cells. The other player then may: (a) choose a color and be the second to move, or (b) choose to move first and the other choose color.
TURN - On each turn, each player must orthogonally slide a friendly stone, pushing all stones it that line, until at least one enemy stone is pushed out of the board.
GOAL - When one player cannot execute a valid move, the game ends. Wins the player with more stones on board.
An initial move

Given this initial position, Black may slide the marked stone at c3 to the north until c5, pushing out two white stones.

Then White can slide b4 two cells down to b2, pushing one white and one black stone. This black stone is pushed out of the board.

This game is presented at 100 Strategic Games for Pen and Paper by Walter Joris.