Fortress:

• It moves, takes, and turns over in an L-shape pattern (two squares in one direction followed by one square perpendicular to the initial movement).

• e6d4: Fortress takes the opponent's Castle.

e6c5: Fortress turns over the opponent's Citadel.

e6g7: Fortress turns over a friendly Citadel.

e6d8: Fortress turns over the opponent's Citadel, promoting to Citadel.

e6c7: Fortress takes the opponent's Tower.

e6g5: Fortress takes the opponent's Wall.

e6f4: Fortress takes the opponent's Fortress.