Wednesday, December 07, 2022 10:47

LV’s Third Notation Course – Computer

After writing my original notation courses, I realized there are two other notation systems in current usage. This course talks about “Computer Notation,” which can be used by humans, too, though I do *not* recommend it.

This course assumes you already know either SAN or LAN. Enjoy!

One notation system that can be used today is called, “Computer Notation.” Ironically, it doesn’t have an abbrieviation. Computer notation is actually much easier to learn, though harder to ‘read’ than SAN or LAN.

Last thing before the Table of Contents. Some people may assume that Computer Notation is the same thing as PGN. It it *not*. PGN assumes that SAN is being used in the move text. Computer Notation was originally written for early chess computers, where both saving bytes and absolute uniformity were two essentials. Just know Computer Notation and PGN aren’t nearly the same thing by any stretch of the imagination (and see Parts 6, 7, and 8 for differences between PGN and CN.)

0. The algebraic coordinate system.
1. Where’s the piece moving from?
2. Where’s the piece moving to?
3. Is a capture occurring? (Optional.)


3A. How to handle two pieces of the same type that could reach the destination square. Same as any other move!
4. Castling!
5. Is there a pawn promotion occurring?
6. Does a move deliver check?
7. Does a move deliver checkmate?
8. What’s the final score?


0. The Algebraic Coordinate System.

Computer Notation doesn’t care about what piece is moving. It only cares about the start and end squares. So we have to somehow number the squares on a chessboard.

One way to divide up a chessboard is to name vertical columns (called files) with letters from “a” to “h”, and then number horizontal rows (called ranks) from 1 to 8. Any square on a chessboard can thus be identified by which file and rank it is on, like the diagram below:

The Algebraic Coordinate System

The Algebraic Coordinate System

(And this is also the origin of the phrase, “rank and file.” :)

The White pieces always begin on Ranks 1 and 2. The Black pieces always begin on Ranks 7 and 8. The Kings are on their proper starting places in the diagram above. The White King always stats on e1. The Black King always starts on e8. (Remember that Queens always take their own color?)

You should always assume that rank 1 (“first rank”) is at the bottom of a diagram, and the file farthest to the left is always the “a” file. Diagrams are almost always looked at as if White set its’ pieces up on the bottom of the diagram.

(I say, “almost.” It may be just barely possible that a diagram is “reversed,” with the 8th Rank at the bottom. But if it is, it will be marked that way by whomever made it. And it is *very* rare. Don’t worry about this at the moment – just assume the bottom row is always first rank.)

Now, you can already identify any square to which a piece is moving from or to, just by naming which file and which rank the piece is on at the beginning of the move. Examples: In the diagram above, the White King is at e1. So, we would start to write “e1___” if it was moving. The Black King is at e8. So, we would start to write “e8″ if it was the piece moving.

1. Where’s it moving from?

In Computer Notation, you begin by simply noting which algebraic coordinate the moving piece is starting from. That simple.

(In passing, the USCF Rulebook’s example uses all capital letters to indicate the file name. I am using lowercase letters throughout this document. Either is acceptable if handwriting the moves.)

2. Where’s it moving to?

In Computer Notation, you end by simply noting which algebraic coordinate the moving piece is moving to. That simple.

3. Is a capture occurring?

There are two main systems at work in Computer Notation.

The first, and simpler, system uses *no* capture abbrieviation. All moves are either notated with a dash in between the from-to square. The “original” version uses no dash whatsoever.

The second system uses “x” to indicate a capture instead of a dash. This is NOT standard, but allowable. In the early days of CN there was no dashes or x’s.

If a pawn on e4 captures any piece at the d5, the notation would be:

Original: e4d5
Dash-only: e4-d5
Dash-with-x-capture: e4xd5

A last note about en passant pawn captures: If you don’t know what “en passant” means, you are not alone. You can visit here, at Wikipedia, to learn more about en passant.

In Computer Notation, one would simply use whatever capture notation is in use, if any. (Logic: If the notation is a pawn diagonal move into an empty square, it *must* be an en passant capture.)

For now, just pick one system and use it. The rest of this document will *not* use “x” for capture, but will dash all moves. (Because the USCF Rulebook’s example dashes the moves.)


Let’s look at the first few steps of a game in diagrams and notation.
In the first move of a game, let’s say White has decided to move the pawn in front of the King two spaces to the light green square below:
If you count files from left to right, you will see this is the “e” File (A, B, C, D, E.) If you count ranks, this pawn is currently on the second rank (“2″.)
If you count the ranks leading to the green square, you will see the green square is on the 4th Rank, and it is still on the “e” file.

Step 1: It is moving from e2.
Step 2: It is moving to square e4.

The move is written:
1. e2-e4

Now, let’s say Black also decided to move the pawn in front of the King two squares:
Step 1: From e7. Step 2: It is moving to square e5. In notation we would write this move after White’s like this:

1. e2-e4 e7-e5

Next, White moves the Knight on the King’s side in front of the Bishop:
From square… g1. Moving to square….. f3! It is White’s second move. We would write the whole game so far:

1. e2-e4 e7-e5
2. g1-f3

Now Black decides to move his Queen’s Knight to protect his e5 pawn:
From b8. To c6. Now we have:

1. e4-e4 e7-e5
2. g1-f3 b8-c6

Now let’s say White gets greedy, and decides to capture Black’s pawn:
From f3. To e5. So this third move is written:

1. e2-e4 e7-e5
2. g1-f3 b8-c6
3. f3-e5

As we leave this interlude, look again at the diagram above. Black now has a chance to capture White’s Knight, only for having lost his e5 pawn. Can you figure out how to write that move?

Yes! It is written just “c6-e5″!

1. e2-e4 e7-e5
2. g1-f3 b8-c6
3. f3-e5 c6-e5

As an exercise, you could take those three moves above and play them out on a chessboard. Though I’m not sure why you’d want to. ;)


3A. Is there two pieces of the same type that could reach the destination square? Same as any other move!

Sometimes two identical pieces can move to a single square. (Without promotions having occurred, only Pawns, Knights, and Rooks can achieve this.)

In Computer Notation, however, this is very easy to deal with. You are recording the starting points of each move, so there’s no ambiguity about which piece was ever moving.

Consider the position after the following moves of a made-up game: 1. e2-e4 e7-e5 2. d2-d4 b8-c6 3. f2-f4 g8-f6. You can look at diagram below:
The Black pawn on e5 is in trouble! Do you see how either the pawn on d4 or the pawn on f4 could take the e5 pawn? When pawns capture pieces, we always write which file the pawn starts on that is capturing a piece. If the White d Pawn captures the e Pawn, we would write it:
4. d4-e5.
If the White f Pawn captured the e Pawn, we would write it:
4. f4-e5.

(In Computer Notation, the absolute key is that every move must be right on as far as origin and destination square. The optional “x” captures can really help you out if you make a mistake. But I’m not using them. :O ;) )

Another pawn capture example, just for fun:
Black decided for his 7th move to take my d Pawn. Even though only the c pawn can make that capture, the move is recorded as:

7. …c5-d4

(The Ellipsis – the funny “…” – means that I’m only showing the Black move here.)

But sometimes two other kinds of pieces can move to a square. For example, from another game:
It’s Black’s 19th move. I wanted to move a Rook to the e8 square. And, by always specifying the starting square, it’s easy!

19. …f8-e8.
(The translation of this is, “f8 to e8.” Since the Rook was on f8, there you are.)

If I’d moved the Rook on a8 instead, it would be:

19. …a8-e8.

I’m cutting out my last example and a paragraph from the SAN course. Because in computers, this problem never really crops up. (Yeah, right! Did you know that most all computer problems can be traced to one singular fault: the nut behind the keyboard. Either the program writer or the user… Except when the computer breaks down physically. :D )

4. Castling!
Castling is the process when both the King and Rook get to move during the same move by a player. It’s the only time that two pieces get to move without an intervening move by the opponent. If you need review on it, here is a link to Wikipedia.

In Computer Notation, one records the move of the King. (Logic: Since the King ordinarily moves one square only, any move showing the King moving two squares must be a castle.)

For Kingside White castling, record the move as: e1-g1.
For Queenside White castling, record the move as: e1-c1.
For Kingside Black castling, record the move as: e8-g8.
For Queenside Black castling, record the move as: e8-c8.

In the following diagram it’s White’s 6th move:

Castles Galore on Move 6!

Castles Galore on Move 6!

White can now castle Kingside, and Black can castle Queenside. If the two sides do that, the moves are written: 6. e1-g1 e8-c8.

5. Is there a pawn promotion occuring? If so, what is the pawn being promoted to?
When a pawn reaches it’s last rank (8th rank for White, 1st rank for Black,) it promotes into any other piece except for a King (and it cannot stay as a pawn.)

Promotion is a special situation in Computer Notation. Different software parsers handle it differently. One system that always works in handwriting:

If there is NO indication of a piece after the move, assume that it is a Queen promotion. If one piece letter is written after the move, that is the name of the piece being promoted to.

(You could also specify the Queen if you wanted to. You could also use the “=” notation from SAN or LAN.)

Look at the following diagram:

It's Promotion Time!

It's Promotion Time!

It is Black’s 30th move. White has just played 30. a1-a2. Black is now going to promote, and will promote to a Queen. In this course, I am going to assume that Black will promote by moving to b1. (Even though capturing the Knight at c1 makes more sense.)

This would be written on the scoresheet either as:

30. a1-a2 b2-b1=Q
30. a1-a2 b2-b1Q
30. a1-a2 b2-b1
(Assumed Queen promotion.)

Note that, unlike the other notation forms, capturing the Knight would simply be b2-c1 and the promotion form chosen.

While it makes no sense in this position to promote to any other piece, here are the other possibilities if Black moved into b1:

Rook: 30. … b2-b1R
Bishop: 30. … b2-b1=B
Knight: 30. … b2-b1N

(Having said all the above, the system that makes the most sense if you are ever hand writing Computer Notation would be the =Piece format.)

6. Does a move deliver check?
The hardest part is over!

If check occurs…. You do not have to notate it.

Think about this… In any notation system, putting down a symbol for a check only serves to emphasize the point. Check is the condition on the board, whether it’s notated or not. ;)

That said, if you want to write the a plus sign (“+”) after the move, it won’t matter. (UNLESS you’re actually hand typing a computer file specifically in Computer Notation for a database or display program to read. THEN it does matter, as some really old software parsers which never expect anything but move sets may blow up on you. The PGN standard, using SAN, does expect it.)

I’m not going to give the other notation course examples, as this is supposed to be simple. If you’re handwriting and want to note the +, go ahead. I’d even recommend that!

7. Does a move deliver checkmate?
Ah, checkmate! That which we all aim for in our games. Sweet victory!

Checkmate follows the same rule as check. Write the “#” if you want to if you’re handwriting it. Strict Computer Notation would say don’t. (PGN would say yes, write it!) Choose either and be my guest! :)

Example – why not?

1. f2-f4 e7-e6
2. g2-g4 d8-h4#

Same as

1. f2-f4 e7-e6
2. g2-g4 d8-h4

These moves should only be made by trained Chess Stuntmen.  Do not try them in your games at home!  ;)

These moves should only be made by trained Chess Stuntmen. Do not try them in your games at home! ;)

Oh noes! It’s still Checkmate either way!

8. What’s the final score?

OK, from the other courses you might know:

1-0 means White won.
0-1 means Black won.
1/2-1/2 means the game was a draw.
* means that the game did not end for some reason. Maybe it’s still being played, or the ending wasn’t recorded for some reason.

Here’s the thing… The PGN format specification also specifically notes that SAN is to be used. So “Computer Notation” doesn’t really care about the end result in the game data.

(Logic: In a software package, the game result may not be part of the “move text,” but rather recorded in encoded headers. PGN double-specifies – the result is also in the headers as well as the move text. Some playing programs might blow up with anything other than move text, though, if expecting CN and not PGN. Now I’ve digressed into technogeek-speak, though!)

But *you* do care! So go ahead and hand-write it!

You now know everything you need to know in order to write your own games in Computer Notation.

Would I recommend it?


Use SAN or LAN.


This whole particular course was simply written up because the USCF Rulebook *does* actually allow you to use CN. But give yourself, your TD, and your opponents a break, please!!!

Your TD might just tell you to stuff your claim if you’ve used strict computer notation. And in that TD’s defense, the TD would have to know Rule 37 on Page 214 and the descriptions to Rule 38E and/or 38H to know that computer notation is allowed. Really, it’s one of those things that in MVHO an ADM should be advanced to force a rules change on to be perfect. But I’d personally be sympathetic to the TD saying, “Use SAN or LAN.”

Now that I’ve gotten that out of the way, here’s the brief steps if you *really insist* on it:

1. Piece moving?
2. From square?
3. To square?
4. How will you account for a promotion?

You’re actually done!

For reading, try the last example of, “e4, e5, Knight to f3, Knight to c6, Bishop to c4, Bishop to c5, Castle Kingside, Knight to f6, Knight to g5, Castle Kingside, Knight to c3, Knight takes on e4, Knight on g file takes on e4, Bishop to e7, Knight to d5, Knight to b4, Knight takes e7 check, Queen takes e7.” In fact, you can probably read and play through these moves right now! Try it:

1.e2-e4 e7-e5
2.g1-f3 b8-c6
3.f1-c4 f8-c5
4.e1-g1 g8-f6
5.f3-g5 e8-g8
6.b1-c3 c6-e4
7.g5-e4 d8-e7
8.c3-d5 c6-b4
9.d5-e7 d8-e7

Here’s the board position, for you to compare to:

The last diagram!  Congratulations!

The last diagram! Congratulations!

You can now write in Computer Notation! (And you can see how hard it is to read computer notation and visualize what’s going on. Which is why only Computers pretty much use it! :D)

Thanks for reading, and
Enjoy your game!


VERSION: 1.4. (Initial release of long: 1.4.)

BONUS: A replayable window of the positions and games above are now available at A downloadable PGN file of the games/diagrams are also available there. Look to the left frame of the screen as you click and step through moves to see Long Algebraic.

FEEDBACK: I appreciate those who have provided feedback and corrections to this article. Feedback can be left here. PLEASE specifiy if you are referring to the Computer Notation course – otherwise I’d assume it’s the SAN course.

Those who have contributed corrections that have been made to the article will be noted here, upon request. Please include if you would like to be credited here, if a correction is published based on your correction. Include the name you want to be credited as.

CREDITS: Page author: Darren Erickson (LaughingVulcan.)

DISCLAIMERS: The examples listed in this page are solely for the purposes of demonstrating how notation works. I may have made errors in this document, as I was translating the origin squares in my head as I was modifying my LAN from before. Games listed here are not intended to be best examples of play. Apply only externally, consult your physician before beginning any mental exercise routine, and the white zone is for loading and unloading only. Did you really read all this? Wow! :)