Discovered Pin

a tactical pattern that cost me two games

Introduction

In this post I would like to focus on an interesting tactical pattern that I missed in two of my recent games (both in late January).

The first instance happened in a weekly sparring game against Martin Justesen, one of the founders of The Chess Gym. The game itself was quite impressive, featuring a little trap in the opening based on my preparation, then an inspired attack by Martin and finally culminating in my blunder of that tactic after prolonged defence. I will look at several critical moments of the game and also describe how I did my opening preparation.

Then, just four days later, I played a rapid game on ChessCom and to my surprise got caught in a very similar pattern. I hope that focusing on that pattern will help me (and my readers) not to miss that again. Or at least not that often.

Game against Martin

Before the game I fired up openingtree.com and started looking at Martin’s games. His main weapon as White is 1. d4 followed by 2. Nf3 and then 3. g3 pretty much against all reasonable Black moves. This looked very similar to recommendations by Christof Sielecki in his popular repertoire “1. d4 - Keep It Simple”. Sielecki suggests delaying 2. c4 in order to avoid complications and main lines. I didn’t have my own clever ideas how to play against this: I would probably just play something natural like d5 and Nf6, but that’s probably what Martin expects! So I turned to Sielecki’s advice and interestingly enough in his book, he is saying that White has to treat one specific variation differently, because otherwise Black can win a pawn: 1. d4 d5 2. Nf3 c5 3. g3 cxd4 4. Bg2 Qa5+!

And now there is no good way to regain the pawn, because the piece that has to block the check also has to block the Queen’s attack on d4 pawn.

If Bd2 - then Qb6 and the pawn is protected. If Nbd2, then Nc6 also protects the pawn, and then if O-O, we can just support the pawn with e4. As compensation White gets better piece development, so we can say that it’s more of a gambit rather than just losing a pawn.

This variation looked interesting and Martin never faced Qa5+, so I decided to give it a try in the game. And indeed, everything went as planned, I won my pawn and was very happy. Some people may dismiss this as some sort of a metagame that has little to do with chess actually played on the board. But I enjoy this preparation phase and I think all professionals do similar things, but of course much deeper. After all, the deepest strategic games eventually descend into metagame and bluffing territory when both players are very strong and mastered the main game (that’s of course not about me). Also, working on opening in such a focused way makes the lines more memorable.

Despite being a pawn up (or rather specifically because of this), later in the game my King was left for too long in the middle and when we got to this position, Martin played a strong inspired move, can you guess it? (If you are from ChessGym, you probably can, because you’ve already seen this):

The move is Nxe5! - a proper knight sacrifice, without a clear way to regain it soon, but starting a strong attack against my uncastled King. After I took the knight, the follow-up was Bd4, and then Rxe6+.

I defended well for long 7 moves, keeping my material advantage and not being mated, but in the following position I made a decisive blunder, leading to the tactical pattern in question. There is a threat of a nasty discovered attack. However, White has abandoned his bishop on d4. What would you play here as Black?

I played Nd5?, trying to block the Queen’s check and at the same time protect the bishop on e7.

And this is where we see this discovered pin idea: true, the knight is blocking the discovered check for the moment, but if the rook on e6 moves, it discovers a pin on my knight! And the rook can additionally attack the pinned knight, so Re5! here won the game.

(If you are wondering, the strongest move in that position was to capture the bishop with Qxd4, which is a difficult line).

Annotated version of the full game can be found in this Lichess study.

Four days later

In the next game with this pattern we’ve got to the following position. I am playing Black and am up a pawn. I have a lot of time on my clock. And do you know what I played as Black?

Rd3?? - setting up a very similar discovered pin pattern. My rook is protecting against the discovered check by the Queen, but then the opponent can still move the rook to g3 and my rook becomes pinned and double attacked:

So the question is: why am I missing this? I think one reason is the desire to play a tricky move and to try to overwhelm my opponents tactically. E.g. in the last position, I could have just escaped the discovery by moving my King to g8, but that probably seemed too lame. And another reason is maybe because this pattern is not too common and I haven’t seen it enough (but how then it happened in two games recently?). It also combines two tactical patterns: the pin and discovery attack, which is neat, but probably makes it more complicated than either of the two. Anyway, there is no definitive answer, but at least by now I will be extremely wary when I try to block a discovered check by another piece!

Outro

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In the next few posts I am planning to share my impressions of Judit Polgar’s great book "How I Beat Fischer’s Record”, summarise European tournaments for traveling amateurs, and also publish my first chess interview! Please consider subscribing, it’s sending me good vibes :)