The chess-playing public views grandmasters as flawless players of the game. However, they are human too. We all make mistakes, and the grandmasters are no exception.
In this week's featured game, one of India's finest players of all time, Viswanathan Anand, makes a tactical slip. This example reminds us that we must consider all possible moves in all branches of our analysis.
It appears to me that GM Anand either disregarded or undervalued the possibility of 27...Qxe7. My analysis concludes that after 27.Ne7+, white is lost. Not capturing the queen with 28.Rxe7 would leave black with a minor piece advantage but it makes little difference white will lose material either way.
The text shows one possible way. At the end, black will be able to exchange two rooks for queen and bishop, leaving him with two bishops and a pawn for white's rook. This is a dominating material advantage in the endgame.
Other moves lead to equally unhappy endings for white. 31.Kf3 Rxe7 32.Qb8+ Kh7 33.a4 Be5 leads to several variations with black ahead a bishop. Play this out and see for yourself.
This is one very good example where a grandmaster would have benefited from a quick infinite move search during his analysis we should all be thankful for the lesson.
White to mate in two moves.