BREAKTHRU

Copyright (c) 1965 Alex Randolph

The game is played on a 11x11 board. The Inner player (the Gold Army) places his 12 soldiers in the central 5x5 area, while placing the King in the center. The Outer player (the Silver army) places his 20 soldiers outside the central area.

This is a possible setup:


MOVE - Each piece slides a straight orthogonal line of empty cells (like a chess Rook). 
CAPTURE - Soldiers can also capture an enemy piece placed on an adjacent diagonal cell.
TURN - On each turn, each player may do one of the following things:
Move two soldiers;
Move the King (for the player playing the King side);
Use a soldier to capture one piece (soldiers capture by replacement but only to an adjacent diagonal cell).
On the first move of the game, the first player (the King side) may pass his turn.
GOAL - The King side wins if the King reaches the edge of the board.  Otherwise (the King is captured or stalemated), he looses. 

An example

Black's turn. He must move his soldiers to prevent the King for reaching the edge. In this position, the Red King loses, because there are always enemy soldiers that can cover all its 4 possible exit lines.

This game is Randolph's answer to Tablut problems (which strongly favors the King's side). Even so, perhaps players should use the Pie rule (you move first, I choose sides) in order to balance the game (especially after some game experience is gathered). Check here for some information.

I wish to thank Yannick JACOB for clarifications about the setup phase.