The squares on the edge that are two spaces away from a corner (e.g., C1, F1, A3, A6). These are generally safer than C-squares but can still offer the opponent access to the edge if not played carefully.
B-Square
The squares in the middle of the edge (e.g., D1, E1, A4, A5). These are often excellent squares for 'Quiet Moves' as they are stable and do not immediately offer corner access.
C-Square
The squares immediately adjacent to the corner on the edge (e.g., A2, B1, G1, H2). Highly dangerous. Playing a C-square usually allows the opponent to 'wedge' and take the corner.
Corner
The four grid corners (A1, H1, A8, H8). The most valuable real estate on the board. A disc in a corner can never be flipped. It anchors stable edges.
Diagonal Control
Possessing a continuous line of discs along one of the two main diagonals (A1-H8 or A8-H1). This is a prerequisite for many advanced tactics, including the Stoner Trap.
Evaporation
A strategy of reducing one's disc count to the absolute minimum (often 1 or 2 discs) in the early game. This denies the opponent flip targets, restricting their mobility.
Frontier
The boundary between occupied and empty squares. 'Minimizing the frontier' is the core principle of mobility strategy. Frontier discs are vulnerable to being flipped.
Interior Discs
Discs completely surrounded by other discs. They cannot be flipped and offer the opponent no moves.
Mobility
The number of legal moves a player has available. The player with higher mobility usually controls the game.
Parity
The property of a region having an odd or even number of empty squares. Controlling parity allows a player to make the last move in a region, which is mathematically advantageous.