keymove

plural keymoves

1. board gamesThe first and most important move in solving a chess problem.

   The study percentage, that is, where the keymove was with a pawn, was 26. So, when in doubt, move a pawn first.

   2016, A. J. Roycroft, The Chess Endgame Study, page 37

   1 more example

   […] a short analysis will undoubtedly convince the solver than the queen is the most likely man to make the keymove. The greatest difficulty undoubtedly will be in finding the second move continuations.

   1961, Kenneth S. Howard, How to Solve Chess Problems, page 137