US Chess Masters 2025 · 2025.11.28 · Elo 2426/2588 · interesting · ★★★★
The daily position for Saturday 3 October 2026. It is still open to solve — the grader reads your whole line, sidelines and evaluation included, before anything here is shown. Cover the solution and solve it first →
White to move. the model gives this to 1 in 437 at this level.
The solution
39.f5!△f6#(not39.♗︎xc5?♕︎xc540.♘︎e4♕︎d441.g3♖︎a7=)39…exf5(if39…♕︎xd4then40.f6#)40.♕︎c6(not40.e6+?♕︎xd441.exf7♖︎xf742.♕︎g3♗︎xg5−+)40…♕︎e6(40…♗︎xg5is as good:41.♕︎c8♗︎f4+42.♔︎h1+−)41.♕︎xc5♗︎xg5(41…♕︎d7is as good:42.e6+♕︎xd443.♕︎xd4++−)42.hxg5♖︎e843.♖︎xe8+−
39.f5 — almost nobody finds this · the threat is f6# — what it plays next if the defence does nothing
40.♕︎c6 — almost nobody finds this · worth +1
41.♕︎xc5 — most players miss this · worth +1
42.hxg5 — the standard move
43.♖︎xe8 — the natural move
“hard to find”, “the natural move” and the rest describe how often this move is played by Maia-2, weighted across the 1500/1900/2000 audience the difficulty model is fitted on — a model of human play, not a count of anyone who solved this position.
Members can take this away as a PGN — the diagram, the verified line and their own analysis in one file, for a database, Anki or Chessable.
What happened at the board
Fus played ♗︎xc5 instead · ½-½
in the game39.♗︎xc5♕︎xc540.♘︎e4♕︎d441.g3♖︎d742.♘︎d6♔︎h743.♖︎a2♗︎f844.♘︎e4♗︎e745.♖︎d2♕︎a446.♖︎xd7½-½full game ↗
The field
38% of the 8 committed lines here found the key move — the model predicted 0% at this level.