8.31 Two players, A and B, take turns placing stones on a $25 \times 25$ grid chessboard. A plays white first, and B plays black. Each new stone must be placed on an empty square, but if a square has 4 neighboring squares (i.e., squares sharing a common edge) already occupied by stones of the same color, then placing a stone of that color in that square is prohibited. If a player has no legal moves when it is their turn, they lose. Who will win when both players use the correct strategy?
[Solution] A wins. A can adopt the following strategy: In the first step, place the white stone in one of the corner squares on the board, then divide the remaining squares into $1 \times 2$ rectangles (see figure). Thereafter, A will place the stone in the other square of the rectangle where B has placed their stone. Clearly, as long as B has a place to move, A can always follow. Therefore, A can ensure victory.