Lessons From Prague 2

THE position in the first diagram below arises from a line in the Semi-Tarrasch that runs (minor transpositions are possible) 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 c5 5.cxd5 cxd4!? 6.Qxd4 exd5 7.e4!? Nc6 8.Bb5 dxe4 9.Qxd8+ Kxd8 10.Ng5.

In this position I have always played 10...Be6, but I am aware 10...Ke8 and 10...Ke7!? are also possible

At Prague with black in round two I played the related line 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 c5 5.cxd5 cxd4!? 6.Qxd4 exd5 7.e4!? dxe4!? 8.Qxd8+ Kxd8 9.Ng5 (see the game for the exact move-order), reaching the following position.

This is the same position as in the first diagram, but without the moves ...Nc6 and Bb5

Previously I have always continued 9...Be6, but, drawing on the analogy with the first diagram, I decided to keep the bishop-pair and played 9...Ke8?

It was only after playing it that I considered what would happen if White replied 10.Bc4, which is indeed what happened, after which White recovers his pawn and has the better position.

Note that, if in the first diagram, Black plays 10...Ke8, then 11.Bc4?! would be fairly pointless as Black has, among other satisfactory moves, 11...Ne5.

LESSON: similar positions are just that - similar, not the same. What applies in one need not necessarily be true in a similar but different position.