Copyright (c) 1992 Claude Soucie
This game is played on a 5x5 square board:
There are 26 white and 26 black stones.
- DROP PHASE - On each turn, each player drops a stone (of either color) into an empty cell or a cell with one stone, until there are just one white and one black stone left.
- PIE RULE - One player drops the remaining two stones on top of two stacks (of size 2) and the other player choose color and who starts.
- Both final stones must not be adjacent and must be over different stacks (i.e., stacks with different configuration of stones).
- MOVE PHASE - On each turn, each player moves his final stone to an (orthogonal or diagonal) adjacent stack (jumping over any empty cells) of size 2.
- The stack where the final stone was is removed from the board.
- [suggested extra rule for larger boards] The final stone cannot move into a stack equals to the stack where the other final stone is.
- GOAL - The winner is whoever stalemates the adversary.
An initial move
This is a possible board configuration just after the pie rule adoption. The final stones are marked in the diagram.
[with the suggested extra rule] If White starts by moving to the left, into b5 he loses the game. Why? Because Black move to b4 (he cannot move to a3 or b3 since those are stacks equal to the stack under the white final stone).
Then White is stalemated: the only possible paths were a5 and c4 but they are equal to the stack where the black final stone stands.
The original game use different colors. I changed the rules a bit to include this game into the Towers section. Obviously, the game can be played with larger boards and with higher stacks (stacks of size 3 could represent at least 8 colors, stacks of size 4, represent 16 colors...). I also suggest the extra rule to improve the game strategy for larger boards.