No one knows who invented Joust, however, Gerry Quinn learned of it by playing it on the Amiga. He then coded a Windows version and released it online, which is how most people have learned of this game. Whoever did invent this game appears to have drawn inspiration from the well-known Knight's Tour puzzle. In this puzzle a knight must traverse an entire chessboard by making legal moves and never landing on the same square twice.
The board is a 8x8 grid of squares. The color of the squares alternate black and white. It is essentially a chess board.
The pieces are one black chess knight and one white chess knight.
To move: Move as a chess knight moves. That is, move one square horizontally or vertically in relation to its current position, and then move one square diagonally in the direction that the piece moved horizontally or vertically. Pieces may jump over opposing pieces. Once a piece has moved, the square it used to occupy can no longer be the landing spot of any piece. This is referred to as "burning" the square.
To win: To force the opponent into a position where he or she cannot move.
Starting Position: Each knight starts on a random square of opposite ranks (rows) on the end of the board. Begin the game with randomly placing a knight on one rank on the edge of the board. The other knight is then randomly placed on the rank that is on the other edge of the board. The first player then moves the knight as it moves in chess. The players alternate making moves while making sure that they do not land in squares that have been burned. A player wins when his or her opponent is no longer able to move.
- Color Advantage: When both knights begin on squares of the same color, the first player has an advantage. This is due to the fact that after the second player's moves, both players will need to land on the same color the next turn. This means the first player can block the second player's move directly.
- Symmetric Strategy: If the board has an even number of squares and both players start in symmetrically equivalent positions, then the second player can always win by copying the first player's moves.
- Control The Center: Overall it is a good idea to try to maintain control of the center of the board. This also means it is a good idea to try to keep your opponent towards the edge of the board. This will limit the number of possible moves they have on their next turn. However, it is important to actually "keep" them there, instead of just pushing them there and then letting them jump out.
- Rule Of Two: The following situation comes up often in the game of Joust. The board is close to being split into two large sections of squares. Generally you want to be left in the larger section of the board then. However, if you have the color advantage, you could either be in the larger section or the same section as your opponent and you will still be favored to win. The key to this, however, is before the board is actually split. There will only be two pathways left joining the two sections. The player to break one pathway will be disadvantaged because the second player will be able to break the second path and thus choose which section to stay on. (All strategies are ideas of Gerry Quinn)
- Misere: If you are in a position where you are unable to move, you win.
- Board Size: The board size can vary from 5x5 to any NxN. 5x5 is an appropriate minimum because of the nature of the knight's move. Also, it is possible to play on non-square boards.
- Starting Position: It is possible to play with fixed starting positions, such as opposite corners. It is also an option to allow the players to choose their starting positions, restricting them to opposite ranks on the board or not.
- Alternate Pieces: It is possible to play with different chess pieces, such as Kings, Queens, Bishops and Rooks. Another option is to allow differing pieces for opponents.
- Grenading: This refers to burning a square other than your previous square. Thus grenading is ranged burning. Grenading has two variants. Piece-type burning refers to burning squares depending on what piece you are. Arbitrary burning means you can burn any square that is unburned or unoccupied. Grenading can also be based on your position prior to moving or after moving.
Quinn, Gerry. "Joust - A Simple Abstract Game." 10 Mar. 2006 http://indigo.ie/~gerryq/Joust/Joustra.htm.
- Joust: A Two Person, Perfect Combinatorial Game
- Gerry Quinn's Mathematical Games Website, Joust Specific Page