1. Promotion Conditions:

Walls: When a Wall reaches the last row of the chessboard on the opponent's side and it is not a turnover, it must be promoted to Citadel.

Strategic Implications

1. Advance with Caution:

Wall Advancement: Walls are generally less critical, but their promotion to powerful Citadels can significantly affect the control and flow of the game. Players should plan their Wall advancements to ensure they are promoting at a strategically advantageous time without exposing critical positions.

2. Using Promotion as a Tactical Tool:

Defensive Promotions: Promoting Walls to Citadels can be a defensive strategy to strengthen a player's control over the board's central or crucial areas. The transformation of a Wall into a Citadel can dramatically shift the balance of power, especially in tightly contested matches.

3. Endgame Considerations:

Citadel Utilization: Once promoted, Citadels offer robust offensive and defensive capabilities. Strategically using newly promoted Citadels can help secure critical positions or eliminate key threats.