Last week I offered you a position from the game Mestel-Renman from the 1980 Chess Olympiad (will there be one in 2020, I wonder?).
Mestel played 34. Rf2 Qh1+ and his king eventually managed to evade the checks, winning him the brilliancy prize. Black could have defended by trying to trade queens: 34… Qc5 35. d4 Qc4.
He should have preferred the subtle 34. Ka2, simply avoiding all checks. Now 34… Qxg2 loses to 35. Qh6, and there’s no defence to White’s many threats: for example Rg4 followed by Rh4.
This doesn’t seem to have been picked up by commentators at the time, so if you found Ka2 you’re doing pretty well.