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 zeros (0-0) instead of the letter O
This is the most frequent one. Castling is written with the capital letter O, not the digit zero: O-O for kingside and O-O-O for queenside. In a hurry, people write 0-0 with zeros, or a lowercase o-o.
- Before:
0-0oro-o - After:
O-O(kingside),O-O-O(queenside)
A forgiving validator will read 0-0 as castling, but strict PGN readers and some database software will not, and a lowercase o-o is even less likely to be accepted. There is no file letter O on a chessboard (files run a through h), so a capital O can only ever mean castling. Write it tall and round, and keep your zeros for the result line.
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) orNfd2(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:
Bf7(when it was actually a capture giving check) - After:
Bxf7+
For pawn captures, remember to include the starting file: exd5, not just d5. Checkmate gets # (Qh7#), and en passant is written as the normal capture square (exd6, optionally exd6 e.p.). Most parsers tolerate a missing + or x because they can work it out from the position. A pawn capture with no starting file is different: d5 looks like a plain pawn push, and if no pawn can push to d5 the import stops there.
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:
Nc3recorded when you playedNc4 - 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
Ke2orRe2 - After: print piece letters clearly, in caps, distinct from your digits
Only five letters ever appear as piece letters, K, Q, R, B and N, so it is worth making each one unmistakable: a K with two clear diagonal strokes, an R with a firm leg, a B closed at both bowls. Pawn moves take no letter at all (e4, not Pe4), so anything that starts with a letter should be obviously one of those five.
6. Skipping a move so the columns desync
A scoresheet has two columns per row, one for 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
On a pre-printed scoresheet the numbers are already there, but on a blank sheet or a notebook page you write them yourself, and that is where they go wrong. The two usual slips are writing the same number twice (12. Bb5 a6, then 12. Ba4 Nf6 again) and jumping a number (12, then 14). The moves themselves may be perfectly correct, but a reader replaying the game now has to guess whether a move is missing or a number was skipped, and a strict parser will refuse the file.
- Before:
12. Bb5 a6 12. Ba4 Nf6 13. O-O Be7or12. Bb5 a6 14. Ba4 Nf6 - After:
12. Bb5 a6 13. Ba4 Nf6 14. O-O Be7
The check is simple: every twenty moves or so, glance at your opponent's sheet and confirm you are on the same number. If your notation still slips into P-K4 and N-KB3 from old books, descriptive vs. algebraic notation maps the old system onto the modern one.
Let the scanner catch them for you
Most of these errors are detectable, because an illegal or ambiguous move stops the game from replaying at the exact spot where the slip happened. When ScanChess reads a scoresheet photo it replays every move on a board as it goes, marking illegal moves in red and doubtful ones in amber with rule-legal alternatives, so the desynced column from mistake #6 or the which-knight problem from mistake #2 is caught at the offending move instead of failing silently in your database.