Copyright (c) 1993 Henri Vergne
This game is played on a 13x13 square board with the following setup:
- GOAL CELL - the marked cells on the bottom and top row.
- PIECES - There are the following pieces:
- Passage stones (in the diagram, the black/white stacks of size 1).
- Rest stones (in the diagram, the black/white stacks of size 2).
- Passage and rest stones may: (i) move to an (orthogonal or diagonal) adjacent empty cell or (ii) jump over (orthogonal or diagonal) adjacent passage or rest stones (of either color) landing on the immediate next cell (which must be empty). Jumps can be multiple but are not mandatory.
- Double stones (in the diagram, the black/white stacks of size 3 or 4).
- Double stones move like passage or rest stones, except they can slide a line of one or more empty cells before they make a jump. Double stones can also jump over the enemy double stone.
- The player can change the size of his double stack from 3 to 4 stones or vice versa. With size 3 they can act as passage stones and with 4 like rest stones, regarding the ball (see below). This size change costs an entire turn.
- The ball (the red stack).
- The ball may move if it is (orthogonal or diagonal) adjacent to a friendly passage stone. Then, if the passage stone is also adjacent to a friendly rest stone, the player may transfer the ball to this rest stone. This sequence can be repeated if the player has more passage and rest stones adjacent to this new ball position.
- However, on each transfer, the ball cannot end in a cell adjacent to its previous position (i.e., each transfer must move the ball at a distance of two cells).
- The rest stone carrying the ball cannot move or jump and cannot be jumped.
- Goal cells are seen as rest stones regarding ball transfers.
- Any enemy piece adjacent to his goal cell can be stacked over with a friendly stack (by jump or move). Covered stacks cannot move or jump. A player can only cover one enemy stack at any given moment.
- TURN - On each turn, each player may do two actions:
- Moves one friendly stack or changes the size of his double stone.
- Optionally, transfer the ball.
- GOAL - The player that moves the ball to the adversary goal cell wins the game.
Some jump examples
Piece b4 can jump over b5 landing on b6 and then jump over c5 landing on d4. But it cannot continue its jump over d3 because d3 is a double stone (rest and passage stones can only jump rest and passage stones).
The double stone at c2 can jump over c5 and then d6. After the second jump it must land at e6 (always land on the immediate next cell).
A transfer example
The rest piece at d5 has the ball. White could transfer it to b4 using c5 and then transfer it to c2 (the double piece is acting as a rest piece) using b3.
White could not transfer d5 to c6 because the ball would be adjacent to its previous position.
A winning example
White's turn. He moves d5 over the enemy stack at c5 (it is legal, since c5 is adjacent to his own goal cell).
Then, White makes the transfer from c2 to b4 (thru b3) and then from b4 to c6 (thru c5). White transferred the ball into the enemy goal cell, winning the game.