ChessBase Christmas Puzzle Week

Christmas day is usually celebrated with a Christmas tree – in problem chess circles occasionally with a puzzle shaped like a Christmas tree. Like this example, composed by the famous Thomas Rayner Dawson, 101 years ago. It illustrates the universal principle of symmetry, and how it can be broken in a chess problem. Mathematics professor Christian Hesse delves into the very profound thinking behind the problem. But you are invited to solve it first.