"Viking" also known as "Hnefatafl" or just "Tafl" is a historical board game widely played throughout Europe before the advent of chess. Archaelogists have found no soild proof of the actual rules of the game, and it is likely that there were many different versions of the game during it's time, but the most likely rules are shown below:
The game is played on an 11x11 grid of squares, two opposing sides having pieces placed on designated squares. Unlike chess, each side has unique types of pieces and differently placed different numbers of pieces. The defenders' side controls the larger "king" piece placed in the centre of the board and the 12 light pieces surrounding him on the marked squares in a defensive diamond-shaped formation. The attackers' side controls the 24 dark pieces placed on the four sides of the board on the marked squares in aggresive "arrow" formations.
1) Moving:
All piece move in the same basic way - the rook or castle's move in chess, that is any piece can move vertically or horizontally onto any empty sqare but cannot pass over occupied squares.
2) Capturing:
A captured piece is removed from the board. A small black or white warrior is captured when two enemy pieces are placed on either side of him (i.e when a piece is between two enemy pieces in a horizontal or verical line). A piece is only captured if an enemy piece makes the move the complete the "sandwhich", in that if a piece were to move into the gap between two enemy pieces, he would not be captured.
3) Capturing the king
The king is captured when he is surrounded on all four sides by black pieces, but can participate as normal in the capture of black pieces. The attackers' side is victorious when the king is captured.
4) The king's sqaures
The kings squares are the four marked squares in the centre of the board (on which the king is initially placed) and in the four corners. The defender's side is victorious when the king escapes to one of the corner king's squares or when all black pieces have been captured. The king can also be captured if he is surrounded on three sides by black pieces and the centre king's square on the fourth. Regular pieces can also be captured if they are "sandwiched" between a corner king's square and an enemy piece. Only the king can occupy a king's square, but regular piece may pass over the centre square.
To move a piece, click on it. The squares that piece can move to are highlighted - click on one of the highlighted squares and the piece will move there. Pieces that are captured are shown on the right pane underneath the text showing the player whose turn it currently is to move.