Described by the author as a mix between chess and checkers, this game is not for purchase but the rules are freely available [only in French though]. Let's go over a brief overview :

GOAL of the game :
Surround the opposing King between 4 pieces (Princesses or Pawns) with a minimum of one of your own pieces.

PIECES :
The King : can't capture/can't be captured/can't jump over pieces and no other piece can jump over the king.

The pawn : you have vertical and horizontal pieces, can capture other pieces. Moves 1 space.

The princess : again : you have vertical and horizontal pieces. May move the full length.