Copyright (c) 2001 Wei-Hwa Huang

The game is played on a 11x19 half Go board, with the following initial setup:

THE BALL - The ball is represented by one black stone. It is placed on the middle of the board.

TURN - Each player on his turn, may do one of the following options .
Drop a white stone (a pressor) into an empty cell adjacent (orthogonal or diagonal) to the ball;
Pass your turn, only if the opponent has not passed on the previous move.
PUSHES - When a pressor is dropped, the ball is "bumped" one space away from the pressor.
If that space is occupied by another pressor, then that pressor is "bumped" one space further, and so on. 
If a pressor on a goal line is bumped, it is bumped "off the edge" and leaves play. 
If a pressor on the edge of the board is bumped diagonally, it "reflects" off the edge and bumps diagonally at 90 degrees to the original direction. 
If a pressor on the edge of the board is bumped horizontally, it is pushed to the side (at 90 degrees to the original direction), away from the player whose turn it is.
GOAL - Wins the player that pushes the ball to the opponent's first line (the goal line).
An example

If a player drops at cell [1] the ball moves to [2] reaching the goal line. The opponent must protect himself, by pushing the ball away from his first line, but he has a desperate position. For e.g., if he plays [3] then a drop at [4] wins the game.

Wei-Hwa Huang also proposes some variants:

1. (Original PP) Players may pass at any time. If both players pass, it is a draw.
2. A pressor may be placed anywhere on the board, and not just adjacent to the ball. In those cases, there is no bumping.
3. Seed the board with a random arrangement of pressors.