Puzzle xACSw_F — ELO 2142
This is a Black-to-move puzzle rated 2142 ELO. The first move is d8d7, tagged with 10 interpretable concepts and Lichess themes: doubleBishopMate, kingsideAttack, mate.
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Position
Black to move. ELO 2142. Themes: doubleBishopMate, kingsideAttack, mate, mateIn5, middlegame, pin, sacrifice, veryLong.
FEN: 2rr2k1/pp2Qpbp/1q4p1/5b2/5B2/1B4P1/PP3P1P/1R2R1K1 b - - 3 21
Show solution (10 ply)
Try to find the move yourself first — look for the rarest concept firing on this position before peeking. Solution sequence: d8d7 b3f7 g8h8 e7e8 c8e8 e1e8 g7f8 f4e5 b6f6 e5f6
Concepts that fire on this position
Our SAE pipeline tagged this position with 10 active features. Each links to a page documenting that pattern in detail.
Why this puzzle is hard
The rarest pattern firing here is A black bishop on an advanced square attacked only by black pawns, with no…, which appears in only 157 of our 9,950 puzzles (1.58%). Rare patterns tend to be the bottleneck — players who haven't internalised them will fail this puzzle even when their tactical calculation is otherwise solid.
The puzzle's Lichess ELO of 2142 reflects this: solvers below that rating typically miss the cue entirely.
Similar puzzles
Puzzles sharing the most concept tags with this one — a stronger signal than theme overlap because it reflects the actual patterns Leela recognises.
Train this pattern
Click through to the Climbchess trainer to attempt the position interactively against the same Leela network that tagged it. The trainer adapts difficulty using your live concept-recognition profile — it surfaces puzzles tagged with concepts you've been missing, not random brawls.
If you want the underlying methodology, the how-it-works page walks through the SAE training run, the labelling pipeline, and the puzzle-tagging procedure end-to-end.
Frequently asked
What is the rating of this puzzle?
2142 Lichess ELO. Solvers below that rating typically miss the key cue.
Which side moves first?
Black to move; the first move of the solution is d8d7.
What concepts does it train?
10 SAE-derived patterns including A queen actively placed on an open rank or file relative…; Detects white king safely castled on the back rank…; White Queen on the 1st or 2nd rank, unthreatened by black….
Can I attempt it without an account?
Yes — Climbchess requires no signup or email. Click the trainer link to play the position interactively.