1. Object

Aporia* is a two-player strategy game played on a two-by-two game board. The game board consists of four large squares, or platforms, and each is further subdivided into four playable corners, or nodes.

Players alternate turns, with each player controlling their respective colored pieces. On each player’s turn, that player may move only a black or white piece.

1.1. Setup

Each player sits across from each other on opposite ends of the game board. Two black and two white pieces should be arranged, side by side, on the four innermost nodes on each platform, while the remaining two black and two white pieces should be arranged, opposite each other, on the outermost corner nodes on each platform.

Players should decide who goes first, with the loser of a previous round of play being entitled to choose the opening player on the subsequent round of play.

• Aporia (Ancient Greek: ἀπορία, "an impasse, difficulty of passing, lack of resources, puzzlement") denotes in philosophy a philosophical puzzle or a state of puzzlement.

2. Movement

On each turn, a player must move either their respective white or black pieces, depending on which color the player controls. There are three rules guiding how pieces may be moved, and a sub-grid built below the platforms can help players direct their movements from node to node and platform to platform.

Rule #1

Pieces can move diagonally along the board’s sub-grid to the next unoccupied node on an adjacent platform.

From the opening board state, the black piece can be moved diagonally in either direction along the sub-grid, from its node on the current platform to the next unoccupied node on an adjacent platform.

Note that the sub-grid does not pass through the exact center of the game board; no piece can move diagonally over the exact center of the board. Additionally, pieces can only ever be moved to an unoccupied node on an adjacent platform; no piece can move from node to node on the same platform.

Rule #2

Pieces can jump over other pieces from one platform to an adjacent platform—but only along the horizontal or vertical axis of the game board, never diagonally.

From the opening board state, the black piece can jump another piece to move to the next unoccupied node on an adjacent platform, but it can only do so by moving along the vertical or horizontal axis of the game board.

Rule #3

A player cannot move a specific piece back to the same node as it was on their own previous turn. Because repetition is disallowed, if no moves are available to a player, the player loses the game. Players may track movements by keeping notes in beginner play, if they desire.

3. Winning the game

There are two ways to win the game. First, a player can lock a platform by moving either all four of their white or black pieces onto the four nodes of the same platform.

The second way to win is to prevent or block your opponent from making a valid move.

No valid moves are available for the black pieces: no black piece can move diagonally to an adjacent unoccupied node on a platform, and no black piece can jump another piece along the horizontal or vertical axis of the board. Note: With respect to the white pieces, it would be true that there are no valid moves available assuming that the piece on the rightmost platform’s outer node had jumped into that position on the turn prior.

If a player cannot make a valid move, then the player loses the game.

4. Gameplay modes & scoring

Before starting a game of Aporia, players should decide on one of two game modes: beginner or advanced. Beginner play will familiarize players with the basic rules of the game, while advanced play will challenge each player’s memory, attention, and foresight.

Beginner Play

For beginner play, players can decide on playing either a single round of Aporia, or a best-of-three or best-of-five series.

Advanced Play

Unlike beginner play, advanced play uses a scoring system, and players should decide on playing a match of three, five, seven, or ten rounds. No note-taking is allowed during play.

The winner of the match is the player who accumulates the most points after the rounds have been completed (or until one player is mathematically eliminated; e.g., if a player is up by 4 points with only one round left to play in the match, that player is the winner since the opponent will not be able to score enough points on the final round).

• If a player wins a round by locking a platform, the player earns 3 points.
• If a player wins a round by leaving the opponent with no valid moves, the player earns 2 points.

If a player intentionally or unintentionally moves a piece back to the same node as it was on their last turn, then the opposing player may choose to challenge that play.

If the challenge is successful—that is, a player can show that the opponent engaged in repetition — then the challenger wins the round. If the challenge is unsuccessful — that is, the challenger was incorrect — then the opponent wins the round.

• If a player wins a round due to a challenge, the player earns 1 point.