How To Read "FEN"

GuessWhoIAm
GuessWhoIAm
Oct 12, 2014, 7:18 AM |
3

Now most of you should have heard or even used "FEN". But if you're unfamiliar to it, then let me tell you that it, along with "PGN" are essential codes used for your analyzing variations.

Here's an example of the "FEN" code for the current Indie Rush VC Match.

"5r2/2p2rb1/1pNp4/p2Pp1pk/2P1K3/PP3PP1/5R2/5R2 w - - 1 51"

Now this may look confusing but thanks to a book I read, it isn't that complicated really.

Before we start translating it, we must first know what represents what (For better and quicker understanding, be sure to frequently refer to the real game while reading this so you can understand it better).

The code will now be divided into a few section with the '|' symbol.

"5r2/2p2rb1/1pNp4/p2Pp1pk/2P1K3/PP3PP1/5R2/5R2 | w | - | - | 1 | 51"

For the first section, you should find out that there are 7 slashes (aka '/') in that section, so dividing the code into 8 smaller sections.

Each small section represents the pieces on each number rank, aka from the '1' file to the '8' file. This changes depending on which side has just made a move. If Black has just moved, as in the diagram, the code will then be turned around. So in this case, it is listed from the 8 file to the 1 file. (However it still reads from the a to h file)

First, let's look at the 8 file in the position. There should be a Black rook on the f-file. As you can see, the section is written as "5r2". The numbers there represent the amount of spaces unoccupied by any piece while the letter represents that piece. So, 5 means that there are no pieces on the a8 to e8 spaces. The lower case letter r represents a Black rook (I specified lower case as upper case letters represent White's pieces. Also remember that 'K/k' = King, 'Q/q' = Queen, 'B/b' = Bishop, 'N/n' = Knight, 'R/r' = Rook and 'P/p' = Pawn.), then 2 represents the empty spaces aka g8 and h8.

Now you should be able to translate the rest of the code on that large section. So we'll move on to the next section. This is quite easy, as only 2 letters can be placed there, aka 'w' and 'b' (lower case only!) representing white and black respectively. The letter placed represents which player is to play next. From the code above, Black has just moved so it is White's turn, so a 'w' is placed there.

The next section, aka a dash ('-'), represents if the players have the ability to do castling. Normally at a starting position that section would be written with 'KQkq'. Again from the previous section, uppercase K states that White can castle kingside, lowercase for Black, while Q and q represents Queenside. Note that even if they cannot castle at that move, as long as castling is possible in the future it will be written.

The next section with the second dash represents the square possible for an en passant. Say in a starting position if White plays 1. e4, then that section would be written as 'e3', to state that any en passant move can only be done there at the move only. Normally only after pawn moves would that slot be filled, otherwise it's a dash.

The next section with the '1' represents the number of consecutive moves excluding pawn moves or captures. This section is mostly used to determine the eligibility for three-move repetitions or the fifty-move rule.

The final section with the number '51' represents the move count for the next move. So according to the game, after Black's 50th move. '51' is written as that is White's next move. Note that if that was White's 50th move, '50' would be written instead.

Hopefully from the guide you can finally understand how "FEN" works. :D