Problem number

https://www.chess.com/puzzles/problem/2453386

needs to be deleted from tactics trainer.

Reason: It is completely ambiguous, both 1.Rxb4 and 1.Qf6 win.

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Reason why the automated system failed to recognize that the problem is ambiguous:

The tactics problem was created and verified with an engine at low depths, where it seemed correct to the engine.

Going to deeper search depths shows that the tactics problem is ambiguous and must be deleted from tactics trainer.

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In detail:

At low search depths, the engines think that 1.Qf6 is the only move that wins. (Tactics trainer system claims that 1.Qf6 etc. is the solution that needs to be found.)

Example: Stockfish 16 Lite at depth 18 :

1. Qf6 +2.18

all other moves : -1.00 or worse

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At deeper search depths, both 1.Rxb4 and 1.Qf6 are considered to be winning by the engines, with 1.Rxb4 even preferred over 1.Qf6 by the engines.

Example:

Stockfish 16 Lite starting at depth 21 or 22:

1.Qf6 +2.41

1.Rxb4 +2.09

(other moves at about -1.00 or worse)

Going any deeper or using stronger engines just confirms this:

Example: Stockfish 16 Lite at depth 40

1. Rxb4 is +3.41

1. Qf6 is +2.90

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Stockfish 16 max at depth = 30

1.Rxb4 4.64

1.Qf6 4.46

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Stockfish 16 max at depth 50

1.Rxb4 5.25

1.Qf6 +4.78

1.Bh6 -1.40

So the automated system has failed about this problem because of a search depth issue.

Is there even a way these days to get the problem removed from tactics trainer manually?

Chess.com - Tactics Trainer Approvers

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