I have a little query: 

 

I think it's called something like en passant. It's where a pawn take another piece by moving 2 moves forward, taking it past the piece, then going diagonal and the piece is taken. Soemthing like that anyway.

 

How does it work and what's the proper name?

 

Many thanks for any advice (relating to this topic). 

En Passant

The last rule about pawns is called “en passant,” which is French basically means “in passing”. If a pawn moves out two squares on its first move, and by doing so lands to the side of an opponent’s pawn (effectively jumping past the other pawn’s ability to capture it), that other pawn has the option of capturing the first pawn as it passes by. This special move must be done immediately after the first pawn has moved past, otherwise the option to capture it is no longer available.

http://www.chess.com/article/view/chess-rules--basics

So if someone moves their pawn two places, so that it is alongside my pawn, I can say en passant, remove his pawn from the board and then take my normal move?

Not exactly. You need to make your diagonal move. If a pawn has moved two squares, just look at it and think about whether you could have taken it if it had moved only one square. If you could have, it means you can take it now, even though it went two squares. But you have to act like the opponent's pawn went just one square. And remember that you cannot wait. If the other pawn went two squares, you do a move other than en passant and decide to do it later, it's not allowed. Hope this helps.

Watch this.

The light has gone on over my head! Many thanks for helping me understand this strange rule.

 

Apart from "Castling" (swapping King and Rook over which I do understand) and en passant, are there any other strange rules which allow pieces to move in odd ways in certain situations?

 

Thanks again 

Just the various rules behind castling. 

1. can't castle out of check (or into of course)

2. can't castle through check.

3. Once the king has moved, castling is no longer an option.

4. And the obvious, can't castle with any pieces between king and rook.  The only place this may not be so obvious is on the queen side.