Slingshot

Slingshot is a traverse connection game played on a 9 x 9 (or 7 x 7) checkerboard, for two players. The game mechanics include the use of a pie rule, opposing traverse goals, and remote custodial flipping. Game play is tense as both players multi-task trying to build their connection path and disrupt their opponent's. It is quick to play, surprising, and captivating.

One player sets up an empty board with like-colored pieces on two different squares, then the other player decides who uses which color. The first player will start game play with the colored pieces not used in the set up. Turns alternate.

The goal for the first player taking a turn is to orthogonally connect the top and bottom sides of the board; and the goal of the other player is to connect the left and right sides.

Each turn, if possible, a player must place a piece on each of two empty squares on opposite sides of a row, column, or diagonal that contains a target opponent piece. To end the turn, a third piece replaces (or "flips") the targeted piece which is returned to its owner.

Dennis the Menace - John Hauser Comics

Figure 1. Sample Game 7 x 7
The symbol "+" indicates custodial placemnents and "n" indicates the target's replacement/flip.

If a player cannot play all three pieces as described above, custodial movement ends. Players instead stack a piece on top of any opponent singleton. The stack is considered neutral and can contribute to paths of either player.

At the end of a turn, a player wins by completing an orthogonal path connecting his/her assigned sides. See Figure 1,

For questions, more detailed rules and figures follow.

"Well-aimed slingshots can topple giants." - Maggie Kuhn

Components

A 9 x 9 checkerboard (7 x 7 also works)
90 pieces, 2 sets of 45, here teal and black

Concepts

Target line is a row, column, or diagonal of squares which contains at least one opponent piece.

Orthogonally connected pieces are two like-colored pieces in two adjacent squares that share an edge.

Neutral stacks contain a piece from each player. These stacks are treated as like-colored pieces for either player.

Connected path is a chain of orthogonally connected pieces.

Goal

The goal is to connect opposite sides of the board with a chain of orthogonally connected pieces, the first player to move (black) is to connect the top and bottom sides of the board, and second player (teal) the left and right sides. Paths can include the game board's corner squares, which are usable by both players. The paths can also include bi-colored neutral stacks that are used to resolve stalemate positions.

The first player to complete a connected path wins.

Game Set Up

To balance the game's opening, either player sets up an empty board with two like-colored pieces (teal). See Figure 2. The other player decides who plays which color (teal or black).

Figure 2. Sample setup

Game Play

Turns alternate, black plays first.

Each turn, if possible, a player must place three pieces.

Two pieces must be placed on empty squares, which are on opposite sides of any row, column, or diagonal containing an opponent piece (the target). These two pieces are referred to as custodial pieces. The row, column, or diagonal is referred to as a target line and can have any combination of empty and occupied squares. In addition, the following conditions must be met:

An imagined line segment connecting the two custodial pieces must be perpendicular to the target line, and
There must be exactly one square (empty or not) on this imagined line segment.

See Figure 3, Sample Custodial Pairs.

To finish, the target piece is replaced with the active player's third piece. The removed piece is returned to the opponent. If this completes an orthogonally connected path, the game ends and the player wins.

Figure 3. Sample Custodial Pairs
The black player is targeting the center teal piece and contemplating where to place her custodial pieces.
The 'a' pair is legal. It does not matter that the square between the 'a' pieces is occupied by either player or empty. Moreover, any combination of pieces and empty squares can be on the target's line.
The 'b' pair is legal. The target can be between the two custodial pieces! The 'c' pair is legal. Note the pair would be placed on squares that are the same color as the diagonal target line. One square must be on the target line between the custodial pair.
The 'd' pair is illegal. The imagined line connecting these two pieces is not perpendicular to the target line.
The 'e' pair is illegal. There is no square between the two pieces.

Stalemate Resolution: A stalemate can occur if a player is unable to place place all three required pieces. The winner is determined using the following procedure:

Starting with the player who was not able to complete a slingshot move, players take turns placing a piece on top of any opponent singleton piece, creating a neutral stack that can be used by either player to complete a path. See Figures 4 to 8.

The first player who completes an orthorgonally connected path using singletons and stacks wins.

Figure 4. Custodial Play Ends
On a 7 x 7 game board, it's Black's turn but he has no legal move because custodial pieces cannot be placed; and neither player was able to complete a path on the 7 x 7 board.

Figure 5. Black's First Stack Move
Black plays a piece at b5 with the intention of later completing a path from b7 to a1 or c1.

Figure 6. Teal's First Stack Move
Teal creates a stack at d4. Other moves would work just as well. Teal wants to connect g4 to a6 or a7.

Figure 7. Black's Second Stack Move
Black plays b3 and completes two winning paths!

Figure 8. Game Over Black Wins
An alternate path from b7 to c1 would also wins. Teal does not get to complete his/her path with b6 or b7.

Please note that for now these game rules may be duplicated and distributed via the web. All rights are reserved. Those that wish to program or sell this game in any form should contact the author at philleduc.pled@gmail.com for permission or a license to do so.

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