You played a beautiful game. You won the exchange, found the only move, and converted in the endgame. Then you got home, tried to enter it into your database, and the import choked on move 23. Sound familiar? Almost every illegible or unimportable scoresheet traces back to one of a handful of recurring slip-ups. Here are the seven most common, and how to keep them off your scoresheet.

The usual suspects

1. Writing the letter O instead of castling notation

This is the most frequent one, and the most confusing for software. Castling is written with capital letter O characters, not zeros: O-O for kingside and O-O-O for queenside. People scribble 0-0 (zeros) or even oo in a hurry.

• Before: 0-0 or o-o
• After: O-O (kingside), O-O-O (queenside)

To make it worse, the file letter O does not exist on a chessboard at all (files run a through h). So if you see an O floating around, it can only mean castling. Keep those letters tall and unmistakable.

2. Ambiguous moves with no disambiguation

When two identical pieces can legally reach the same square, the bare piece letter is not enough. Nd2 is meaningless if a knight on b1 and a knight on f3 can both go there. You have to say which one.

• Before: Nd2 (which knight?)
• After: Nbd2 (the b-file knight) or Nfd2 (the f3 knight)

The rule: disambiguate by file letter first; if both knights share a file, use the rank number instead (N1d2 vs N3d2); only if that is still ambiguous do you use both. Rooks are the usual offenders here too, e.g. Rae1 vs Rfe1. See our full guide to chess notation for the complete disambiguation hierarchy.

3. Forgetting the capture x or the check +

These symbols are easy to drop when you are low on time, but they carry real information. A move that should read Bxf7+ becomes a vague Bf7, and now a reader cannot tell whether anything was even on f7.

• Before: Nf3 (when it was actually a capture giving check)
• After: Nxf3+

For pawn captures, remember to include the starting file: exd5, not just d5. Checkmate gets # (Qh7#), and en passant is fine as the normal capture square (exd6, optionally exd6 e.p.). Missing a + rarely breaks software, but a missing x or pawn file often does.

4. Mixing up similar piece destination squares

Under time pressure, c3 and c4 look awfully alike, and so do e4/e5 or a stray b next to a 6. One transposed digit turns a legal move into nonsense and desynchronizes everything that follows.

• Before: Nc3 recorded when you played Nc4
• After: double-check the rank digit before moving on

The fix is simple discipline: write the move immediately after you make it, while the board still matches your memory, not three moves later.

5. Illegible piece letters (K vs R, B vs ...everything)

Handwriting is the enemy. A rushed K and R are nearly indistinguishable, and a sloppy B can read as a P or a 6. When a piece letter is ambiguous, the whole move is suspect.

• Before: a squiggle that might be Ke2 or Re2
• After: print piece letters clearly, in caps, distinct from your digits

A good habit: pause your K with a clear crossbar and give your R a firm leg. Pawn moves take no letter at all (e4, not Pe4), so anything with a letter should be obviously one of the five officer pieces.

6. Skipping a move so the columns desync

Scoresheets have two columns, White and one for Black. Forget to record one half-move and every entry below it shifts up a row. Suddenly White's brilliancy is sitting on Black's line and your move numbers lie.

• Before: White 12. Bb5, then you forget Black's reply and write White's 13th move on Black's side
• After: if you miss one, leave the cell blank or mark it, and resync before continuing

This is the single most damaging error because it corrupts the rest of the sheet, not just one move. Our walkthrough on how to fill out a chess scoresheet covers the column discipline that prevents it.

7. Wrong move numbers (and the occasional descriptive-notation relapse)

Two related slips here. First, miswriting a move number, often by repeating one (12..., then 12... again) or skipping ahead. The moves may be correct, but the numbering confuses anyone replaying it.

Second, and rarer among newer players: accidentally lapsing into descriptive notation, the old P-K4, N-KB3 system. If you learned chess from a vintage book, it can sneak out under pressure.

• Before: P-K4 or N-KB3
• After: e4, Nf3 (standard algebraic notation)

Modern databases, tournaments, and tools all expect algebraic. If you are unsure how the two systems map, our piece on how to read a chess scoresheet breaks it down.

Why these mistakes matter

A scoresheet is only useful if someone, or something, can replay it. Tournament directors use it to settle disputes. You use it to analyze and to build your database. A single ambiguous knight move or a desynced column can make an otherwise perfect game unimportable, and you lose the record of your best work.

The good news: most of these errors are detectable. An illegal-move or ambiguity check will flag the exact spot where the game stops making sense, which is usually the exact spot where you made the slip.

Let the scanner catch them for you

This is where ScanChess earns its keep. Snap a photo of your handwritten scoresheet and it converts your moves into clean SAN and a ready-to-import PGN. Crucially, its move-legality validation flags illegal and ambiguous moves as it reads, so the desynced column from mistake #6 or the which-knight problem from mistake #2 gets caught right at the offending move instead of failing silently in your database. You can review the flags, fix the one bad entry, and replay the corrected game on the spot.

If you would rather start from the board than the sheet, the same engine reads a photo of a position into a FEN. And when you just want a clean export, convert your scoresheet to PGN or learn more about how we scan chess notation.

Write neatly, disambiguate your knights, keep your columns in sync, and let the scanner double-check the rest.

Ready to digitize a game? Scan a board or scoresheet now and start with free credits.