Copyright (c) 19?? Frank Harary
This game is played on any square board (say 8x8):
- TURN - On each turn, each player drops a neutral stone on an empty cell provided that it does not share the same row, column or diagonal with all the stones already on board.
- GOAL - Wins the last player to move.
The green dots show the remaining valid cells. So, the next player will drop one stone there and win the game.
Some possible variants (the first two are Harary's suggestions, the others are mine):
- Use stones of two colors (the restriction is only applied to stones of the same color).
- Use other restrictions (only row and column, only diagonals, chess knight connections ...)
- Use obstacles (neutral pieces that stop the range of the dropping pieces). These obstacles may be initially placed on board, or may be part of a player's personal reserve.
- Allow the drop of several different pieces (e.g., a chess army)
- Players may drop everywhere, but if a player detects an invalid position he wins.
- Each player must drop two stones each turn, but he may optionally remove a stone already on board before the two drops.
- Replace the drop phase with an initial invalid position. Pieces move using their range and may capture by replacement. Wins the first player that achieves a valid position (with valid meaning "no piece attacking another").
This game title is mine, I don't know the original name but will be glad to hear it if someone does.