Copyright (c) 1992 Christian Watkins and Jan Kristian Haugland

Pleiadis is played on an empty NxN (N should be even, say 12x12) square board:

  • TURN - On each turn, each player drops a stone on an empty cell
    • The only valid cells to drop are those where the number of (orthogonal and diagonal) adjacent enemy stones are less or equal than the number of friendly stones.
  • GOAL - Loses the player with no valid move.
An example

The red dots show where Black can drop, while the green dots show White valid moves. The d3 cell is valid for both players.

Some words from the author: With sensible play, the difference in mobility will usually shift between +8 and 0 in the opening in favor of the first player. Therefore, it might be a good idea to introduce a komi-rule like in Go with about 4 points, or to require the first player to make the first move along the edge. Without any kind of handicapping, the game would not be very interesting on a board with an odd number of squares in each direction, since the first player could play in the center and then mirror the other player's moves.

Also check In Crowd, a related game.