Having plucked the only book I really need to study from my collection of nearly 600 (yes, I have a problem!) to get to FM strength, namely Dvoretsky’s Endgame Manual, I elected to start at the beginning.
The first section covers pawn endgames – I like these as they are great for calculation training. Fairly simple “counting” exercises on the face of it that become monstrously complex very quickly.
Key squares is the first topic of the chapter and despite thinking I understood this concept very well, the following example was rather instructive.
J. Moravec, 1952 : White to play… Solution here
Dvoretsky, M. (2008) Dvoretsky’s Endgame Manual. 2nd ed. Milford: Russell Enterprises, p. 15