Memory

An exercise from Chess.com this morning was made simple because I remembered one that I composed for my book, Essential Tactics: Building a Foundation for Chess Skill (2017).

White to move

The decision to trade rooks in Exercise 1289523 hinges on whether White can seize the opposition. 

White to move

White must outflank with Kg5. All other moves draw.

Exercise 14 in Essential Tactics begins with a tactical sequence.

White to move

After forcing the exchange of bishop and rook for Black's queen, White faces an elementary queen and pawn endgame. However, those who have learned the principle of opposition poorly--thinking opposition is the end, rather than the means to an end--can fail. The White king must outflank Black's king.

White to move

In this case, the distant diagonal opposition is sufficient. Black's king is one square closer to the pawn than in this morning's exercise. This difference suggests perhaps that it was a faulty memory that helped me solve the exercise on Chess.com.