HanniBall was invented the 6th, 7th and 8th of April 2009, without board or pieces, to show that an idea can 'explain itself' by listening carefully, the very point I try to make in this very essay. I didn't quite succeed. The main flaw turned out to be a dominant strategy for the player in possession of the ball, coined catenaccio. This was remedied with a rule against clustering, suggested by Arty Sandler of iGGameCenter, where you can play the game live. You can find the story in a nutshell in late arrivals & final whispers.

hannibalRules

Board
The board is a rectangle of 9x13 squares, with two additional goals of 1x3 squares. There are two 'goal areas' of 2x5 squares.
Both players, White and Black, have 11 pieces: 1 Keeper, 2 Lions, 4 Elephants and 4 Horses.
The diagram shows the board with the pieces in the initial position. The ball lies in the centersquare.

Object
The object of HanniBall is to shoot the ball into the opponent's goal. If a player shoots the ball into his own goal, he loses the game.

Moving and capturing
White begins and players move in turn. Each turn a player is allowed to make up to 4 moves, which must lead to at least one change in the position. However, white on his first turn may make no more than 2 moves.

A 'move' may be:
  1. Moving a piece that does not have the ball.
  2. Moving a piece that does have the ball, with or without it (the latter barring the Keeper).
  3. Shooting the ball.

Shooting the ball can only be done by a piece that has the ball in its possesion. The pieces move and shoot as follows:

  • The Horse moves as the knight in Chess, but may not jump to its target square if both the in between squares are occupied by pieces. A Horse shoots the ball 'king's move' wise. If a Horse shoots the ball, it lands on a straight or diagonally adjacent square.
    Note that a knight's move is always possible between a cornersquare of the goal and the backrow of the field on that side (for instance b2 and d1), because there are no two intermediate squares beween these squares.
  • The Elephant moves as the king in Chess. An Elephant shoots the ball 'knight's move' wise. If an Elephant shoots the ball, it lands on a square one knight's move away, no restrictions.
  • The Lion combines the options of Knight and Elephant, so it moves and shoots either way in any combination.
  • The Keeper moves as a Lion, but may not leave the goal area (except for the goal itself). A Keeper in possesion of the ball, may not let go of it other than by shooting it (that is, he may not move and leave the ball behind). A Keeper shoots the ball up to five squares away, queenwise. Direction and distance are the player's choice, but the ball must land outside the goal area.

Inside the goal the Keeper or a defender should not have the ball in its possession, because a ball inside the own goal immediately ends the game in a win for the opponent.

The Ball
The Ball may land on any square, whether or not occupied.

  • If a piece moves to a square where the ball is, it takes possession of the ball.
  • If the ball lands on a square occupied by a piece, other than a Keeper, the piece takes possesion of the ball.
  • If a player is in possesion of the ball, and it is his turn, and he has still one or more move options left, than he can do one or more of the following:
    1. Shoot the ball.
    2. Move the piece and take the ball along.
    3. Barring the Keeper: move the piece and leave the ball.
    4. Move another piece.
  • If a player is in possesion of the ball, and it is not his turn, then the piece holding the ball can be captured by the opponent. Capture is by replacement. The captured piece is taken off the board, and the capturing piece takes possession of the ball.

Please note that if a player shoots the ball to an opponent's piece, and he has still one or more move options left, he may, if he can, capture that piece!
Note also that the opponent's goal is a freezone with regard to such an action: a player would have to shoot the ball into his own goal to do so, and thus lose the game.

Shots at the goal or the Keeper
  • If a player shoots the ball into the opponent's goal, he wins the game. If he shoots it into his own goal he loses.
  • If the ball is shot to a square occupied by a Keeper of either side, the ball 'ricochets' off the Keeper, queenwise, up to five squares, but not into the goal (though it may land in the goal area). Direction and distance are determined by the shooting player, whether the shot is directed at a player's own Keeper or the opponent's Keeper.

Note that a Keeper can only take possession of the ball by picking it up in the goal area, or by capturing a piece there, that is in possesion of the ball. A Keeper in possesion of the ball risks capture like any other piece.

Obstruction
Obstruction is a 'red card' offense against the rules. It is permitted, but may and usually will be punished.

  • If a player on his turn finds a position in which he has at least one piece other than a Keeper, and not one of his pieces can reach the ball in any number of moves, then the opponent has committed obstruction and the player to move may (but is not obliged to) remove one of the opponent's pieces from the board as his first move. This may or may not be a blocking piece.
    If the obstruction is still in place at the beginning of the blocking player's next turn, he must to undo it himself, or risk having yet another piece removed.

Clustering is another 'obstructional' offence. It limits the size of 'groups' of like colored pieces.

Definition: A 'group' is a number of like colored pieces that are orthogonally connected. The ball, if it is not in a piece's possession, is a 'like colored piece' for both players and can be part of a black or a white group, or both. If the ball is in possession of a piece, only the piece is counted as part of a group.


Clustering
Clustering is a 'red card' offense against the rules. It is permitted, but may and usually will be punished.

  • If a player on his turn finds a position in which one or more of the opponent's groups occupy more than three squares then the opponent has committed clustering and the player to move may remove one of the opponent's pieces from the board as his first move. This may or may not be a 'clustering' piece.
    If the clustering is still in place at the beginning of the clustering player's next turn, he must undo it himself or risk having yet another piece removed.


How I invented ... hanniball
External links

HanniBall © MindSports and Arty Sandler