Hnefatafl

Hnefatafl is an asymmetric game — one side defends, one side attacks. You choose which side to play.

1. Defenders control 12 pieces and the King (gold). Their goal: escort the King to any corner square to escape.
2. Attackers control 24 red pieces surrounding the board. Their goal: capture the King before he escapes.
3. All pieces move like chess rooks — any number of squares orthogonally, blocked by other pieces.
4. Capture: sandwich an enemy piece between two of your own (or between your piece and a hostile square). Captured pieces are removed.
5. Hostile squares: the center throne and all 4 corner squares act as capture partners for both sides — even when empty.
6. King capture: the King is only captured when surrounded on all 4 sides by attackers (or 3 sides + throne).
7. Only the King may land on corner or throne squares.
8. Shieldwall: a row of pieces against an edge, flanked at both ends, is captured all at once.

Hnefatafl (pronounced roughly "NEFA-tah-fel", meaning "King's Table") is a family of asymmetric Norse board games played across Scandinavia, Iceland, Britain, and Ireland from approximately 400–1000 AD. The game appears in multiple Norse sagas and Eddic poems, and boards and pieces have been found in Viking Age burial sites across Northern Europe.

The asymmetry of the game — a small defending force escorting a king to safety against a numerically superior attacking force — directly mirrors the political and military reality of Viking Age raid-and-defend dynamics. The game was eventually displaced by chess as it spread through medieval Europe, nearly disappearing from history.

This implementation uses the Copenhagen ruleset, the most rigorously reconstructed and playtested modern interpretation of the historical game, including the shieldwall capture mechanic documented in historical sources.