Coin Volcano

About Coin Volcano

Coin Volcano is a single-player ▶️ Viking tafl game 🎮: hnefatafl, the Norse "king's
table 📋", on an 11x11 board. The two sides are not mirror images of each other.
One side is a king and twelve guards, drawn up in a cross around the central
throne, trying to walk the king out to one of the four corner refuges. The
other is a host of twenty-four raiders ringing the board edges, trying to
surround the king on all four sides. You choose which side you take.

Pieces slide orthogonally over empty squares, any distance, like a rook. You
capture by sandwiching an enemy piece between two of yours, or against the
empty throne, or against a corner refuge. Nothing else moves the way it does
in chess or checkers, and because the two sides have different piece counts
and different win conditions, playing guards feels nothing like playing
raiders.

Four AI opponents give the game 🎮 its range. Thrall, Huscarl, Jarl and Konung
search 🔍 one, two, three and four moves deep with alpha-beta search, move
ordering and a fixed node budget 💰, so the lower tiers make real mistakes and
the higher ones plan 🗺️ around your cordon. The evaluation weighs material, the
king's open rays, his distance to the nearest refuge, guard cordon integrity
and how completely the raider ring is closed.

The forecast overlay is the second layer of the game 🎮. It draws three channels
of heat on the board: threat, which of your pieces the opponent can take next
move and how many ways; opportunity, which enemy pieces you can take next
move; and escape lanes, the corridors the king can use to reach a refuge in
two moves or fewer. Long-press a piece and every legal destination is marked
with the captures it would win and a warning ring if the square itself is
capturable. Each channel toggles independently, and you can turn the whole
thing off.