Design a Chess Game

Requirements

• A standard 8x8 board with the standard piece set (king, queen, rook, bishop, knight, pawn).
• Each piece type has its own movement rules; the game must validate a move before allowing it (including whether it would leave the mover's own king in check).
• Track turn order, detect check/checkmate/stalemate, and maintain a move history.

Key classes to identify before you look at the reference

Every piece type moves differently, but they're all still "a piece on a board that can be asked for its valid moves." What relationship between Piece and its subtypes (Pawn, Rook, …) makes "ask any piece for its valid moves" work without the board needing a giant switch statement on piece type?