DrGridlock: This game is annoted by Keres in "The Complete Games of Paul Keres."
While the opening was home-cooked by Keres, Kotov's 9th move (Qc4) deviated from Kere's analysis, and the Knight sacrifice 10 Ne6 was found by Keres "on the fly."
After 6 Be2, Keres writes:
"I had definite reasons for choosing this move in the game. Kotov always employed in this variation a development system akin to the Scheveninengen with the moves Q-B2, P-K3 and B-K2, and I had prepared a new type of attacking continuation precisely against this."
After 9 Bh5, Keres writes:
"The chief idea of White's opening system centres around this original Bishop move, which is desinged to prevent Black's method of development by B-K2 followed by 0-0. On account of the threat of 10 KtxP, Black must now choose other paths far removed from the Schevinengen line. ... White has achieved a psychological victory in that he has diverted his opponent from the prepared opening variation. And in such cases it is not easy to find the right move at once over the board."
After Black's 9 Qc5, Keres writes:
"It is interesting to note that in my own preparatory study of the line I had not at all taken into account this natural move."
After 10 Nxe6, Keres writes:
"After an exhaustive examination of the position, however, the interesting idea occurred to me of initiating a sharp attack with this Knight sacrifice aimed at the enemy King which has been left too long in the centre. The sacrifice in question is not based on exactly calculated variations but more on general considerations. I thought that after accepting the sacrifice Black would have great difficulties with the defense, since White is considerably ahead in development and will soon be in a position to set up some harassing threats."