Among the many interesting moments in the recently concluded Irish Championship was the following from the encounter between Anthony Fox and Dermot Nolan in round 6.
53. ?
I was following the game live, and expected to see 53. Qd3+, which wins after 53… Qxd3 54. Bxd3+ Kh5 55. Bxa6, when Black can extend the game only via 55… f2 56. Kg2 f1=Q+ 57. Bxf1 Rc8, but then Black cannot stop the pawns.
I was surprised when Lichess showed 53. c8=Q played, and even more surprised when this was quickly corrected to 53. c8=R. What on earth was going on?
Tim Harding, also watching, speculated that the initial promotion used an upturned rook to signal a queen, but that the arbiter corrected this, and John McMorrow confirmed this account. This caused surprise in some quarters, as Anthony is a very experienced player, and the upturned rook has been outlawed for many years. Everyone was feeling the pressure!
As pointed out by Tim, this mishap ironically helped Anthony, as Black could have drawn via 53… Rxc8 54. Qcx8 f2+ (or 53… f2+ 54. Kh2 Rxc8) 55. Kh2 Qe5+, when White cannot escape the checks. Presumably Black would have been more likely to capture with a queen on the board. Instead, after 53… f2+ 54. Kh2 Rf3?, Black was lost.
From the diagrammed position, it turns out that 53. Qd3+ is the only way to win.