Trickiest Puzzle Ever - Mate in 1

White to move - Mate in One

There is no way to prove that Black's last move was d7-d5 ...

Except that it's mate in one... And that there would only be one way to block the check from Qh1+ that allows said mate in 1

Impossible

There's no way to get to 1...d5 without 1. Qh1+

IDK if this is right

En passant d6, only if the last Black move was d7 to d5. Otherwise, there is no mate in 1. (And no, I didn't find the answer by looking at @alexandersukos's board, it was well under by screen view)

Way to go, babe!

Thanks Peewee.

exd6 en passant checkmate

The correct task would be: "find the last move of Black so that in a position on the diagram White can mate in one move."

Or more veiledly: “In this position, White has checkmated in one move. How is this possible?”

Or rephrased for context "In this position from a free game in 1928 Alekhine checkmated his opponent in one move. How did he do that?"

I don't think so. When information you need to make a decision is unavailable you cannot simply assume it has the values you want to make your solution work. The end state of a puzzle is a goal you must attain and not a preset fact you can lean on.

What you made is (among regular puzzle makers) known as a joke puzzle. You probably never noticed but there are countless puzzles where white could win by starting with an e.p. move. To forestall a mess, the puzzle makers agreed to disallow e.p. moves unless provable from the past. For castling moves it is the opposite, they are allowed unless disprovable.

Btw, your idea is not anywhere near original. I dare say no month goes by that not a very similar puzzle is posted on a chess.com forum. It's just yawn, yawn and yawn again.

Probably more often than monthly (at least on average) but at least once a month is probably the safest way to word it to still include the slower periods.

One thing that is sad is that if the puzzle started with the White queen on b2 and Black pawns still on c7 and d7 then the puzzle would work (1 Qg2+ d5 2 exd6 e.p.). All of the pieces except the White King are involved in the mating net.

PS In puzzle rush the last opposing move is shown and thus you really do know whether or not en passant is possible.

Which Magnus? Carlsen? Unthinkable he would present this other than as a joke. Even when he is not a puzzle expert he knows enough about them to know where to draw the line. In a puzzle environment without Magnus on the podium you need to add a text like in post #11 or #12 - and there are other ways to introduce it as well.

All this has nothing to do with "being critical". Since chess is a deterministic formal mathematical system, most of its statements can be evaluated objectively. The results of the evaluation are not "criticism" but "conclusions".

I think if an 800-900 player found the solution, it's just not that big of a deal. Jokes are supposed to be funny right? I've never seen somebody pull out chess diagrams at a stand-up. If there were other ways to solve it in one move it wouldn't make sense that you could do en passent. By process of elimination, the only logical conclusion to reach mate in one is the only possible solution. To suggest that there is no critical thinking because "chess is mathematical" is ludicrous. The way in which positional evaluation has evolved, and continues to evolve, mathematically is due to critical shifts in thought patterns by which we assign value to different discrete concepts within given positions. Even in positions as simple as this one, the process of evaluating alternatives to no avail requires the solver to think outside the box. Now just because you've seen puzzles like this and have the advantage of pattern recognition doesn't mean you didn't have to utilize this process initially and that people who haven't seen it shouldn't be given the same opportunity to think creatively.

It's like saying, yeah I've seen smothermate a million times. Everyone on chess.com forums please don't share chess knowledge I know. It wastes my time.

There are literally hundreds of thousands of new members every day. Your knowledge should not outweigh their opportunity.

Just move on.

The issue is about rules - and the rules of chess are defined to the template of a formal mathematical system - rephrased to be readable to common humans. What I and others have tried to explain to you is that supplementary choice rules exist to determine the resolution of unknown states in diagrams such as e.p. right. Your reasoning about "elimination" is fictitious as it changes the existing "choice rule" for e.p. right. You can change a rule when you announce it with the puzzle presentation and not as an explanation in the discussion

Of course, you can always announce the puzzle as a "joke" but not as a "trick" since chess is full of tricks which misdirects the solvers.

The reference to "critical thinking" makes no sense in any of your posts which is why I assigned a different interpretation to it - a quite legitimate one in the free association between adjectives and nouns in natural languages. So I can revert now to my original understanding that it is "senseless".

Game players do not understand puzzles The basic reason is that there are no unknowns in a chess game. That's why you must keep records for an arbiter in a physical game. Such that he can always check the history to decide issues not visible on the board. Puzzles have no game records and therefore demand some way to resolve historical issues. These are called choice . rules. More than 50% of all puzzles are flawed without choice rules. Choice rules do not pick options by desires about the future but from assessment of the past - the expectancy of an e.p. possibility is small and therefore it is rejected. If you play Ra2-a4 as the first move to the solution of a puzzle, black could claim a draw on the basis that you are moving in a game in which already 49 moves without capture or pawn move had passed and now we are at 50 - draw. The weird idea in your minds is that only white can fill in the "free space" by some elimination idea. Black has a goal too and will insert his own vision of history as the only way to escape from being mated. That is his elimination program. Btw, when solving a puzzle you are supposed to make the best moves and decisions for both sides - as if you are sitting near a physical chessboard. Chess.com has corrupted this fundamental making everyone believe they only need to consider one side (commonly white). Only 30 years ago you would have been ridiculed to death for naming that "puzzle solving".

Too complicated I suppose. I'm sure you chose your username for a good reason

So let me add this puzzle to demonstrate. Yes, it is a joke puzzle but one StockFish (not Komodo) will solve correctly while you probably do not! Btw, some chess.com puzzles are based on the same joke but chess.com is in the process of deleting them. Their justification was the same as yours. You can only solve these puzzles if you tune the missing information to deliver the "desirable" outcome.

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One big problem with saying that e.p. has to be there (since it is the only way the puzzle works) is that there have been many puzzles presented where the only way White wins is if Black makes multiple blunders during the solution of he puzzle. The composers have claimed that "the solutions have to include blunders by Black since otherwise it doesn't work" (those composers have become quite irate when people point out that better moves by Black not only avoid mate but give Black a winning position, and their response is almost invariably something on the order of "it is obvious that Black blunders in the solution because otherwise the solution doesn't work"). Similar to your statement that Black's last move had to be d7-d5 to get out of check, overlooking that Kc7 was available and there was also the possibility that the pawn had been on d6 instead of d7 (there are truly clever puzzles where the solution is dependent on proving that Black's last move had to have been a two-square pawn move because that is the only way the position could be reached by any sequence legal moves). That is why I suggested a slightly different starting position with the White queen on b2 and Black having two pawns instead of one (on c7 and d7) so that nothing had to be assumed and d7-d5 was a forced move in the solution rather than a potential move in the prerequisite to the solution.

Another big problem is that there have been numerous puzzles presented with did not work within their own constraints even if blunders by Black were assumed (overlooking that Black still has moves out of check in the puzzle composer's "final position". Thus a natural evaluation in those cases is that the composer made a mistake.

There is also a group of puzzles where the puzzle position is impossible to reach by any sequence of legal moves (White having pawns on g2, h2 and h3 is one example and one side having 9 pawns is another of the many examples).

The moment I first looked at this one I saw it as clearly being in the large group of "en passant puzzles where the composers think they are being clever and are the first person to come up with something like this". For that matter, I suspected it before even opening the thread just based on the thread title being similar to the titles in other en passant dependent puzzles.

There is an old theme. I don't remember a specific puzzle but think of this:

White Ra1, Kc1, Qc3, Re3

Black: Kd5, Bf4, Qc6, Rc7, Rc8, Pa2, Pa3, Pb3, Pg2, Ph2

White on move wins.

In the unlikely event that nobody figures it out I'll give the answer in about 12 hours.

I'd not say white is 'on move' but he is definitely 'on the move'