Copyright (c) 2001 Gigamic Publ.

This game is played on the following 5x5 square board:

TURN - On each turn, each player must do one of the following things:
Move a stone - a stone moves to an empty cell (see the board with a 45º left rotation) forwards or diagonally to the left or right (no jumps and no captures)
Shift a row of cells: players can move a row/column of 5 cells if the row/column contains at least one of their stones. 
All stones in that row/column move one cell in the shift direction.
A stone on the edge appears on the other side.
The only way of moving a stone backwards is to shift a row. 
KO rule - You cannot reverse an opponent’s move.
The stones are removed from the board when they reach the corner cell which is opposite to their home base.
GOAL - The first player to remove 3 stones wins.
An example

Black's turn. He may move to cell [1] removing the 3rd stone and winning the game! 

If it was White to move, the red dots show what were his possible single moves. But his best move would be to shift the 'b' row to the left, placing the a2 Black stone at cell e2.

You will find the detailed rules at Gigamic's QUITS webpage.