Two kings facing each other with one square between them. A particularly important concept in endgames, a tactic to control the opponent's king by direct confrontation and seize the initiative. The king forced to move is at a disadvantage

The act of building piece formations or creating positions. Refers to optimizing piece placement and positioning across the entire board

A square where your piece can be stably placed without being attacked by enemy pawns. Particularly when located in the center or enemy territory, it becomes a strategically powerful stronghold. "A knight needs an outpost" (Steinitz)

A tactic of burdening one piece with multiple defensive duties or roles, ultimately making it unable to defend everything. A technique of overworking a piece to break through its defense. Overload

Missing important threats or opportunities in your own or opponent's moves. Besides blunders, this includes overlooking your own attacking chances or opponent's threats