So many puzzles have false mate motif

@KusanagiZerg said ^

Lichess's definition:

The Opera Mate works by attacking the king on the back rank with a rook using a bishop to protect it. A pawn or other piece other than a knight of the enemy king's is used to restrict its movement. The checkmate was named after its implementation by Paul Morphy in 1858 at a game at the Paris opera against Duke Karl of Brunswick and Count Isouard, known as the "The Opera Game".

Not sure how but it would be good to change the wording of the description, right now it can be read as:

"A pawn or other piece other than a knight" of the enemy king's

or as

A pawn or other piece other than "a knight of the enemy king's"

@plopsky said ^
I'm sorry, but I completely failed to understand what you were trying to say. Also, English isn't my native language, so I use a translator.

@AquilaReale64 I think this would be a much clearer description

The Opera Mate works by attacking the king on the back rank with a rook using a bishop to protect it. The kings own pawn or piece (other than a knight) blocks the square not attacked by the rook and bishop. The checkmate was named after its implementation by Paul Morphy in 1858 at a game at the Paris opera against Duke Karl of Brunswick and Count Isouard, known as the "The Opera Game".

@plopsky said ^

The Opera Mate works by attacking the king on the back rank with a rook using a bishop to protect it. The kings own pawn or piece (other than a knight) blocks the square not attacked by the rook and bishop. The checkmate was named after its implementation by Paul Morphy in 1858 at a game at the Paris opera against Duke Karl of Brunswick and Count Isouard, known as the "The Opera Game".

Yes, that would be a more accurate definition. But the problem is that this definition comes from Wikipedia. The Lichess definition allows for too much ambiguity: "Check the king with a rook and use a bishop to defend the rook." Lichess should publish more accurate descriptions for checkmate patterns.

Actually the description I gave was a slight adaptation of the definition Lichess itself provides in Training (in Puzzles they indeed provide the minimal one that you mention).

I guess the main problem is that this mate is not well defined in an authorative source, so Lichess is forced to pick its own interpetation.

For example I checked 4 other chess/puzzle sites and each had a different definition. And even wikipedia is not consistent as strictly speaking the english definitions of the opera mate and Mayet mate fully overlap.

Considering all this I think lichess did not make a mistake in choosing the definition, and we should be happy to get puzzles like this https://lichess.org/training/XML80

@plopsky
A broader or narrower interpretation? Personally, I favor the narrower one. After all, mate puzzles don't necessarily have to fit a specific checkmate patterns. Everybody can solve the mate puzzles in mates -> checkmates section, and that's actually better because there are no hints (if you know the pattern, you can figure out which figures are needed to checkmate, etc.). Also in epaulette mate: checkmate must be provided by only queen or rook also can? Different definitions provide different answers to this question. Or in corner mate: king should be in the corner or can be somewhere in another place? https://lichess.org/training/I19WH https://lichess.org/training/vR9uq
The opera mate example was chosen merely as an illustration. I get the impression that in this thread people thinks the problem lies solely with this pattern. Problems with broad interpretations (or even completely incorrect tags) also exist in other motifs.

I understand it was only 1 example pattern, but it was a good example.

My personal conclusion is that lichess often needs to chose the definition themselves and narrow or broader is just a matter of taste.

However, if you see a definition and the puzzle goes against that definition, then I recommend voting it down