Copyright (c) 1980 Max Gerchambeau

7 Sages is played on the following board (the central neutral stone is called the ball) :

GOAL AREA - The central five cells of the player's first row.
OUTSIDES - The edge cells around the central area (the marked cells in the diagram).
MOVE - A stone may move on the following ways:
Slide diagonally or orthogonally into to an empty cell, except diagonally backward.
Slide diagonally or orthogonally (with no restrictions) into the ball. Then:
The ball slides in the same direction of the previous moved stone, and must meet another stone (friendly or foe) bouncing on it, making a 90 or 180 turn. The pivot cell is the cell just before the bouncing stone.
The ball can bounce more than one time on several stones.
It is the player that moved the ball that decides where it ends its movement.
The ball cannot move into the outside, but it can bounce on stones that are there. 
A stone may move into the outside.
A stone may move thru the opponent central area, but is not allowed to stop there.
A player cannot have more than one stone on his goal area (they may be empty).
Point - If a player moves the ball into the opponent's goal area, it scores one point. After that move, the stones resume the initial position and the opponent starts moving. 
GOAL - Wins the player to score five points.
An opening example

If the Black stones move northeast, it will move into the ball, which slides at the direction until it meets another stone. Then it may turn 90 degrees (at the pivot red cell) or turn back.

I wish to thank Claude Chaunier for information about the game.