Copyright (c) 1996 Nicolas Herlas, Strate&J Publ.

This game is played on a 6x6 square board with the following setup:

LEVEL - Each cell has a level, depending on the ring it is:
The cells inside the central 2x2 square have level 0.
The cells inside the middle 4x4 ring have level 3.
The cells inside the outer 6x6 ring have level 6.
STACK - The player that has the top stone controls that stack.
HEIGHT - A stack A is higher than a stack B, if the number of stones of A plus the cell level that A occupies is higher than the number of stones of B plus the cell level that B occupies.
TURN -  On each turn, each player must do one of the following things:
MOVE - A player may move the top stone of one of his stacks to any adjacent (orthogonal and diagonal) empty cell (the cell level does not matter). This means that the stack looses one stone.
CAPTURE - A stack higher or equal than an opponent's stack may move its top stone into the lower stack capturing it. 
A captured stack flip the color of all its stones.
SURRENDER - A stack lower or equal than an opponent's stack may surrender. Then the first stack goes under the second stack, without changing the stones color (the bottom stones are the prisoners) .
When a stack has a majority of prisoners (more than half) then the whole stack is turned over to the surrenders color!
GOAL - Wins the player that owns all stacks.

An example

The top left stone is lower that  stack at b6 (3 stones plus level 6 < 5 stones plus level 6) . Black can surrender it, putting the stack under b6. Then, the whole stack will have 5 black stones and just 3 white stones, so the stack turns into a 8 black stone stack!

On the bottom right corner, the white stack cannot capture, since it is on a lower level than its opponent (it could surrender but it would not be sufficient to flip the black stack). White could try to save the top stone moving it to an adjacent empty cell.

There is some information at this website (in French).