Here is one of Papp Erenburg’s very nice victories, against Gabor Papp of Texas Tech. In this stubborn Petroff defense, in which both sides contend for the center, Erenburg exchanges a pawn for two tempi and thus obtains a passed pawn and victory.
a) 6. Nxd7 is thought to be the most testing move here.
b) Also 11. . .g6 is reasonable.
c) Perhaps 12.Bd4 is a better move. The plan White adopts of winning Black’s a-pawn looks dubious.
d) The position is actually not completely clear if Black “blunders’’ the exchange: 13. . .Rxa7(?!) 14.Qe3+ Qe7 15.Qxa7 Qb4 with the twin threats of 16Bd4+ and 16Qxb2, but such speculative play is only suitable for a blitz game. Of course the move Black actually plays is the correct one.
e) Note that 15.Qxf5?? Bd4+ blunders the queen. The resulting position is quite favorable for Black. His two bishops, active pieces and play against White’s weaknesses more than compensate for the loss of the a-pawn.
f) Not 18.Ne4?? Bxe4 19.Rxe4 Qd5, forking the rook and bishop.
g) Perhaps when calculating 16.Rae1 White missed that 19.Bxd4? Rd8 20.Re1 Bg4! loses material.
h) The result of White’s last few moves is to imbalance the position even further, which in general favors the side with the two bishops.
i) Black threatens 30. . .e2+ and 31e1=Q, and after 30.Kh1 Qd1+ (or 30Bd5) 31.Qf1 (or 31.Nf1 e2) 31e2, it’s all over for White.