UML chess rank piece rule pawns chess object name type level position

 https://forum.unity.com/threads/unity-3d-chess-project.67097/

 https://www.geeksforgeeks.org/design-a-chess-game/

 https://en.wikipedia.org/wiki/Rules_of_chess

https://www.chess.com/forum/view/chess-openings/pawn-structure-classification-codes?page=2