Copenhagen Hnefatafl Rules: The Full Official Ruleset

Copenhagen Hnefatafl is played on a 11×11 board between 24 attackers and a defense of 12 soldiers plus a king. Attackers move first. All pieces move like rooks; soldiers are captured by sandwiching, the king by full encirclement; the defense wins when the king reaches a corner square. The full ruleset follows.

These rules were developed by the community at aagenielsen.dk, home of the World Tafl Federation, finalized in September 2012, and used for championship play since 2013. This page restates them in plain language; the original publication at aagenielsen.dk remains the authoritative text. For the variant’s background and character, see the Copenhagen Hnefatafl overview.

Board and setup

The board is 11×11 with five restricted squares: the central throne and the four corners. The king begins on the throne, his 12 defenders around him, and the 24 attackers in four symmetric groups at the board edges. The setup diagram on this page shows the exact position, rendered from this site’s engine data.

Restricted squares may only be occupied by the king. Any piece may pass over the throne while it is empty, without stopping on it.

Movement

The attacking player moves first, and turns alternate with one move each. Every piece, king included, moves any number of vacant squares along a row or column. No diagonal movement, no jumping over pieces of either color.

Capturing soldiers

A soldier is captured when an enemy move traps it between two enemy pieces on directly opposite sides along a row or column. Moving voluntarily into such a gap is safe; only the aggressor’s move captures. One move may capture multiple soldiers in different directions at once.

The restricted squares are hostile and may replace one of the two capturing pieces. The four corner squares are hostile to soldiers of both sides. The throne is hostile to defenders only when empty; it is hostile to attackers whether empty or occupied by the king.

The king participates in captures: he may serve as one of the two flanking pieces exactly as a soldier would. In the standard terminology, the Copenhagen king is armed.

The shieldwall capture

A row of two or more soldiers standing on squares along the board edge may be captured together. Conditions: the entire row is bracketed at both ends by enemy pieces standing on the edge, and every soldier in the row has an enemy piece directly in front of it (on the adjacent square away from the edge). A corner square may take the place of one bracketing piece.

The bracketing move must be made by the capturing player. If a king stands within the wall, he is not captured by it, but the soldiers beside him are.

Capturing the king

The king is captured when attackers occupy all four squares orthogonally adjacent to him. If the king stands on a square adjacent to the throne, three attackers plus the throne suffice. The king is never captured against the board edge, and never by fewer pieces than these rules require. Capturing the king wins the game for the attackers immediately.

Winning the game

The defenders win when any of these occurs:

1. The king reaches any corner square.
2. Exit fort: the king stands on the board edge, has at least one empty square to move to, and is enclosed within a formation of defenders that the attackers cannot break.
3. The attackers cannot make a legal move.

The attackers win when any of these occurs:

1. The king is captured.
2. Encirclement: the attackers form an unbroken ring around all remaining defenders, including the king, with no defender able to ever break it.
3. The defenders cannot make a legal move.

Repetitions and draws

Perpetual repetition is forbidden and loses for the defending side: the player repeating a board position endlessly must vary or forfeit. A game is drawn only when neither side can possibly force a conclusion, for example with material too reduced for either win condition. In practice, Copenhagen games end decisively.

Notes on this restatement

Nothing above alters the aagenielsen.dk ruleset; where wording differs, the original governs, and this site’s engine implements the original. Two clarifications worth making explicit because they generate questions: first, the safe-move principle (entering a sandwich voluntarily) applies to the king as well as soldiers; second, the throne’s hostility is asymmetric between the sides, as stated in the capture section.

The mechanics are explored with worked examples in the capturing guide and the king guide, and the family-wide reference with variant comparisons is hnefatafl rules. To see the ruleset in action, play it now; the engine enforces every clause on this page.