Every 2 or 3 years I give in to utter madness and take up playing chess again. This is madness because I’ll never be as good a chess player as I wish I could be, and I’m just good enough to realise how bad I am at the game. It’s also utter madness because there are — seriously this is true — probably hundreds or thousands of 10 year old chess freaks geniuses out there in the world who understand the game in ways I never will.

Still, there is one joy to be had whenever I take up chess again, and that’s in trying to get Darren Saturday to believe in the existence of the ‘en passant’ pawn capture rule.

Yes, this post is going to be very dull, and very chess-nerdy. You are encouraged to go do something more interesting while I rant about this; which shouldn’t be hard to achieve, and why the hell are you still here? It’s not like you haven’t been warned.

A strange sense of Deja Vudoo

Saturday has conveniently forgotten this, but I fought the long, hard and bitter battle of convincing him that the en passant pawn capture rule truly exists, once before.

Back then – probably more than 10 years ago now – he was calling it “Murray’s Bogus Umpy Pumpy Manoeuvre”, and his unwillingness to acknowledge that maybe he was wrong led to a breakdown in communications that eventually saw him fleeing the State ahead of the mighty wrath that is Murray @ Midnight when he’s miffed [1].

Funny thing being, it’s one of the two standard rules of chess that predictably freak out everyone when they first hear about them [2].

Even so, the en passant rule is the kind of thing you really want to know about if you ever decide to rock up to a chess club. Let’s face it, chess players are not universally known for their finely-honed social skills [3], and they’re not the kind of people to forgo the making of snide comments about your lack of basic chess knowledge, given the chance.

The Umpy Pumpy Rule

The whole point of the en passant rule is that a pawn that hasn’t yet moved has a special ability. On its first move, it can jump ahead two squares instead of just 1. The player doesn’t have to move it the two squares if he or she doesn’t want to, but the option is there, just in case.

Because pawns get this special, once-off ability to rush a little faster into battle, they also take a small extra risk should a player decide to go ahead and move his or her pawn those two squares. But that risk only materialises if an enemy pawn is in a position such that it could have taken the moving pawn if it had only moved one square.

This is probably best described with a diagram, and oh look, here’s one now.

Right. Imagine the black circle is where the black pawn started from, and the white pawn is sitting there, smugly, on g5.

The person playing the black pieces decides, ‘Hey, you know what? I’m going to move my black pawn from f7 2 squares to f5, instead of just 1 square to f6, because that pawn hasn’t moved yet, and it would be amazingly cool if I did so. People will acknowledge my chess superiority, and I will get all the girls, because they are obviously into guys who know these things.’

But not so fast, player of the black pieces! You haven’t taken into account the en passant pawn capture rule!!

You see, as the player of the white pieces, I also have this once-only opportunity to take that daring black pawn as it whizzes past the normal capture square (in this case, the white pawn on g5 would only normally be able to attack pieces diagonally, on f6 and h6). This is because, in theory, the black pawn passes through [4] the f6 square, and for a brief instant was vulnerable to attack by the white pawn on g5.

So, as the player of the white pieces, I have the option to sneakily ambush that evil black pawn as it’s rushing into battle, which means that the black pawn is removed from play, and the white pawn ends up (in the case of the example in the diagram) on f6 where ‘x’ marks the spot in the diagram.

Simple, right? … Hello?

Yeah, but…

Why people have trouble believing in the existence of the en passant rule is because most of the other pieces in chess can also move multiple squares (with the exception of the King), and yet they can’t be attacked ‘in between’.

This is absolutely true, and no-one really knows exactly when this strange little arrangement for the pawns made its way into the game.

Current theory is that it’s a relatively recent development in the history of the game, first added somewhere about the 14th or 15th Century AD. It’s also thought that the pawn’s ability to move 2 squares on its first move and the ability to take that pawn if an enemy pawn is placed in just the right position were both adopted into the main ruleset of the game at about the same time.

Beyond that, the rest is mystery.

Some further reading, just in passing…

For a brief summary of the rules of chess, see: Wikipedia, Rules of chess

For a slightly more in-depth look at the en passant rule, see: Wikipedia, En passant

And from there, well, Google is your friend.

Murray @ Midnight