A critical middlegame position is on the board. Black has stacked up all the pieces on the d-file. In fact, whites rook on e1 is the only piece except for the kings that is not on the d-file. The position looks simple and the solution looks simple too! The patterns shown in this problem can arise in many different positions, even with different pieces than those on this board. If you already clicked in Bd3-h7+ and to your amazement discovered that this is the wrong move, take a moment to understand why and look for better options. Think, calculate and only then move the pieces. This habit will radically increase your chess results.