“It often happens that a player carries out a deep and complicated calculation, but fails to spot something elementary right at the first move. In order to avoid such gross blunders, the Soviet master B. Blumenfeld made this recommendation:-“When you have finished your calculations, write down the move you have decided upon on the score sheet. Then examine the position for a short time ‘through the eyes of a patzer’. Ask whether you have left a mate in one on, or left a piece or a pawn to be taken. Only when you have convinced yourself that there is no immediate catastrophe for you should you make the planned move.”— KOTOV Think Like a Grandmaster
And just to show that it works:
“Back in the days when William Steinitz was Champion of the World, he published a lengthy analysis of a defence which he considered to be a refutation of the Evans Gambit. It took up pages of print in his publication The International Chess Magazine, and impressed layman and expert alike.Steinitz was interviewed by the press and referred to by them as the destroyer of the gambit. The line he advocated ran as follows:1 P—K4 P—K4 2 N—KB3 N.QB3 3 B—B4 B—B4 4 P—QN4 BxNP 5 P—B3 B—R4 6 P—Q4 PxP 7 0-0 N—B3 8 B—R3 NxP 9 Q—N3 N—N4 This position is reached:
Steinitz’s adopted daughter glanced at the position, and smashed the whole line by asking why White should not play 10 BxPch NxB I I R—K1ch, winning the queen. This two-move win almost broke Steinitz’s heart, as he was subjected afterwards to a great deal of disparaging comment. “CHERNEV At Random CHESS July 1976 p.322
I honestly don’t know how good a player she was, so patzer may be a gross calumny, but that fresh look is invaluable.
N.B. Actually writing your move down before playing it is now considered by FIDE to be note-taking, and thus forbidden by the Laws of Chess.