visayanbraindoctor: The psychology of missing a tactical shot.
Why in the world would GM Motylev, a leading positionally solid top master, allow a pawn grab by Kramnik in a more or less even game?
20. Rab1; and Kramnik grabs the a-pawn Qxa3
The simplest explanation is that I think Motylev just missed a tactical shot.
I think Motylev was thinking of Bh6 in some variations, but moving the bishop out of the h2-b8 diagonal in order to attack allows the black queen to occupy it with a check Qd6+ once the white knight is gone, and this piece can be taken anytime by Black's bishop on c8. He just might have missed this possibility. Some psychological factors possibly involved.
1. The Black Queen has to place herself in the a3-f8 diagonal to get to d6.
2. The White Knight on f5 has to disappear.
3. The White Bishop on f4 has to disappear out of the h2-b8 diagonal.
Only after these occur would Kramnik be able to move Qd6+. Anticipating a devastating attack on the Black King with themes of Bh6, Qg5, Nxg7 Motylev got himself into a trap of his own making.
Kramnik BTW is pretty good in NOT missing these tactical shots relative to other top masters, although he also occasionally does.