Not 19.a4 Qxe2 20.Rxe2, because of 20...Rc1+, and it is White who is mated!
Unity Chess Club
Grigory Levenfish Nikolai Riumin Moscow 1936 White to move
Black has no bolthole for his king, his bishop is undeveloped, and the dark squares around his king are weak. White could exploit these factors by means of...
In the game, White missed this possibility, and after 27.Ng3 Qb5 28.Rfe1 Bb7, the game equalised out.
Unity Chess Club
Oleg Korneev 2561 Devaki Prasad 2407 Port Erin 2003 White to move
White’s pieces are harmoniously placed: he controls the c-file, the Ne3 stops Black playing ...d6-d5, and at the same time works on the kingside, while the white queen looks at both flanks. All of these factors, plus the weakness of the kingside dark squares and of the back rank, allow White to land a decisive blow:
44.Nf5+ gxf5 45.Rh8 f4 46.Rcc8 also gives a decisive attack. However, the fact that the white attack is decisive here too is not immediately obvious.
Unity Chess Club
Viswanathan Anand 2775 Michael Adams 2710 London 2012 Black to move
White’s last move was 41.Be2-c4, probably counting on 41...Bxc4 42.Rxc4 Qd6. The position had been absolutely equal, and, losing concentration, White probably thought he could draw however he liked, so he carelessly offered the exchange of bishops. However, he forgot about the back rank, and there followed: