Nova Daily - 3 May 2026: A genuine and insignificant mistake (Recap Week 18)
Hi!
With the publication of the monthly results, the April month has officially ended in TBA. Since two of the main bloggers participated in the contest, it wouldn't make sense for either of them to publish the results, and so I did.
In pretty much the same way as I did in earlier judging efforts, I had a spreadsheet and a Word document ready to keep score and write notes. This was very useful, because in several cases I have something to say about the blogs that were submitted. In one or two cases I noticed a minor mistake, and I can't mention that before the results come in. If I'm the first to judge someone's blog that contains a massive blunder in the writing, and the author changes that upon my recommendation, the other judges would be looking at a different blog that's improved because of one of the judges, and that's not fair to the rest of the competition. And so I've waited until the results were published.
In one case, I noticed something that was wrong in the blog, and this turned out to be an oversight by Chess.com themselves.
A genuine and insignificant mistake
As you will understand, I work a lot with PGN files for my writing and my OTB prep. As such, I've looked at PGN-files and FEN-strings for years. I've always found it useful to learn about this, and so I've delved into deciphering the letters, numbers, code, and what-not well before @DocSimooo wrote his monograph on the Da Vinci Code of chess.
Having done my own research beforehand enabled me to verify everything in the blog, and I can say that at present, the blog is almost fully correct. Almost fully: there is one tiny detail that I saw isn't correct. And it's such a tiny inaccuracy that even Chess.com and Wikipedia have it wrong, and I assume that several other sources would, too.
The halfmove clock
The halfmove clock is the penultimate variable in FEN-strings. It is the tracker for the number of halfmoves (or "plies") that have been performed since the most recent irreversible change in the position.
When you think of "irreversible changes to the position", you would automatically think captures and pawn moves, because pieces don't respawn and pawns don't go backwards. However, these are not the only irreversible moves in the position. There are two other types of moves that constitute an irreversible change in the position. In the next excerpt, I've used an example of both of them:
The halfmove clock resets a total of eight times in this fragment. Six of them are pawn moves. The other two are 6.Rh3 (White forfeits the right to castle kingside) and 8...Bc5 (Black forfeits the right to capture the f-pawn en passant). However, Chess.com has the halfmove clock sitting at 7 and 1 respectively.
It's a very minor detail, and one that will almost never matter. However, there has been a recent game in which the forfeited right to castle was instrumental for the game duration. While strictly not about the halfmove clock, the issue is the very same:
The software declared the draw for them. However, commentator, former World Championship Challenger and not-a-suspect-in-VOB's-murder-mystery Peter Leko predicted that it would end in this draw. Note how he understands that the kings have to be back on e2 and e7:
ChessBase has it right. I hope that Chess.com will follow soon.
The week in chess
Another not-really-spectacular week has gone by. Thanks to the fantastic efforts of 24 bloggers, I've been rather preoccupied with reading a lot of great stuff. And so I've only done a few things to stay afload and keep some routine going.
That said, I didn't do nothing at all.
My current scores:
Rapid rating: 2411 (=)
Blitz rating: 2624 (+17)
Bullet rating: 2561 (+11)
Survival: 63 (=)
Puzzle Battle: 2209 (=)
Puzzles: 2566 (+65)
Repertoire: 4497 moves (=)
