Rules of Copenhagen Hnefatafl 11x11.
1. Two players may participate. One player plays the king's side, with a king and his defenders, and the other player plays the attackers. There are twelve defenders and twenty-four attackers.
2. The game is played on a board with 11×11 squares and with initial set-up as shown:
3. The central square, called the throne, and the four squares in the corners are restricted and may only be occupied by the king. It is allowed for the king to re-enter the throne, and all pieces may pass through the throne when it is empty.
The four corner squares are hostile to all pieces, which means that they can replace one of the two pieces taking part in a capture.
The throne is always hostile to the attackers, but only hostile to the defenders when it is empty.
Five restricted squares.
4. The attackers' side moves first, and the game then proceeds by alternate moves. All pieces move any number of vacant squares along a row or a column, like a rook in chess.
Moving a piece.
5a. All pieces except the king are captured if they are sandwiched between two enemy pieces, or between an enemy piece and a hostile square, along a column or a row. The two enemy pieces should either be on the square above and below or on the square to the left and to the right of the attacked piece. A piece is only captured if the trap is closed by a move of the opponent, and it is, therefore, allowed to move in between two enemy pieces. A captured piece is removed from the board and is no longer active in the game. The king may take part in captures.
Capture of pieces.
The piece is not captured.
5b. The shieldwall rule for capturing a row of pieces on the board edge: A row of two or more taflmen along the board edge may be captured together, by bracketing the whole group at both ends, as long as every member of the row has an enemy taflman directly in front of him. A corner square may stand in for one of the bracketing pieces at one end of the row.
The king may take part in the capture, either as part of the shieldwall or as a bracketing piece. If the king plus one or more defenders are attacked with a shieldwall, the attack will capture the defenders but not the king.
6a. The objective for the king's side is to move the king to any of the four corner squares. In that case, the king has escaped and his side wins.
The king's side wins.
6b. Exit forts: The defenders also win if the king has contact with the board edge, is able to move, and it is impossible for the attackers to capture him after any amount of moves.
7a. The attackers win if they can capture the king before he escapes. The king is captured when the attackers surround him in all four cardinal points. When he is on a square next to the throne, the attackers must occupy all surrounding squares in the four points of the compass except the throne.
The king is captured.
The king is not captured.
7b. If the attackers surround the king and ALL remaining defenders, then they win, as they have prevented the king from escaping.
The attackers win by encircling all defenders.
8a. Perpetual repetitions are forbidden. A player who maintains a board repetition ("the aggressive player") must find another move to break the repetition, or he loses the game.
"The aggressive player" is the player who continually side steps with a piece in order to find an open path to break through. The other player continually brings his piece in line with the aggressive piece in order to block the open path. In other words, "the aggressive player" is the one who has some choice in whether to repeat the pattern or not.
If a board position is repeated for the third time, "the aggressive player" loses the game.
Perpetual repetition - the king must find another move.
8b. Draw forts are forbidden: If the defenders repeat the defending board position three times while no piece is captured, the attackers win.
(Only in force when the defenders have at least king plus four men left, which is the minimum of pieces needed to build a fort).
Draw forts forbidden.
9. If a player cannot move, he loses the game.
The defenders cannot move and lose.
10. The game is a draw if no capture has been made in the last fifty moves (for this purpose a "move" consists of a player completing his turn followed by his opponent completing his turn).
The Copenhagen rules were outlined 2012 by Adam Bartley (Norway), Tim Millar (UK) and Aage Nielsen (Denmark).
The Copenhagen game pieces in the online game were sent by Gregory Binns (USA).
Part of the text above reuses formulations from Sten Helmfrid's text (Sweden) on the Skalk variant. Hat tip also to Konstantin Jaehne (Germany), David Brown (UK) and Damian Walker (UK).
Try out the game at aagenielsen.dk