Josif Kricheli
1st-2nd Prize e.a., J.B.Santiago MT, 1964-65
A perfectly constructed problem showing interesting dual avoidance.
1.Be8 Sd7 2.Rf8 Rf4 and 1.Bf8 Sc6 2.Ra3 Rc3.
After Black’s unpin White must anticipate which waiting move Black has available by selecting the correct knight destination to ensure that the mating move prevents an interposition on the long diagonal.
Richard Stein: This made for short, sweet solving. Black has to begin by unpinning the knight, and at his second turn he doesn't have a waiting move that leaves the mate undisturbed, except in one case where White can block the disturbance.