Hardest mate in 1 puzzles

 @Omar_shaker 26  en passant?

FutureRain, we are supposed to deduce that from the position, since no other move can give mate in 1.

@futurerain its just like aln67 said, You have to deduce it cuz nothing else gives you mate in one! I love that one!

The real point with remellions puzzle is proving that c6-c5 mate is not legal, it is of trivial matter to get to that position with the pawn on c7. I don't think it's possible, the configuration of pieces makes sure that the last possible move could only have been bxc3 but then the bishop has to be promoted. Tricky stuff.

The other one is truly difficult. I tried f4 '#' (Ba8) Re3 '#' (Kf4) but nothing seems to work. At least there is the queen swing maneuver.

Black's last move must have been ...b7-b5. The King could have not have moved from b6 where it would have been in an impossible check from two different white pawns. The pawn could not have moved from b6 where it would have been checking white with black to move. So, we may play 1.axb6ep# since we know for a fact that black just moved his pawn forward two squares.

FAIL - you don't just assume it because it's the only move that seems to mate in 1!

You have quoted a composed problem without understanding the real point of it.

chesskingdreamer,

I copied remellion's post into a database I have in order to get a good look at all possible moves. The correct answer, in white print, is Qh2#. Highlight to see the answer. I realized, looking everywhere the king could go that white's bishops and queen were cutting off the escape square so I knew all that needed to be done was place a piece so it would attack the square that the king was on. Looking at all different possible options, I saw that white could either block with a piece except with pawn to f4. However, that move is illegal. So I had to re-examine the position until I was able to see this move.

En passant in a problem done properly, is such that the position allows you to logically conclude, as BigDogg did above, the last move was a double pawn move. Therefore, en passant is legal only because the last move *must* have been the double pawn move, and no other last move was at all possible.

For my en passant problem, the solution is here. chaotic_iak supplies the solution there; ...c6-c5+ would be impossible because white's only possible last moves before that were either bxc3 or c7xb8=B - and both require too many captures to be possible.

I apologise to BigDogg: I've more or less forgotten how to make good retros. :P
Therefore, another regular mate in 1. Again, only one move is actually a mate. (Amazing how annoying these can be, given it's only 1 move deep!)

Remellion, not entirely certain if we were supposed to find mate in 1 for black (which is impossible as the only checks for black result in the pieces being taken) or for white. If white, then Qe8#. Highlight to see answer.

Added note to Remellion--

Love your puzzles by the way. One thing I've been trying to improve on is forcing moves when it comes to the king. What escape squares does the king have, etc.?

I think you should look at your keyboard while typing...

Not quite...black could have promoted to B on a1.

why help?

@Teddyhead: No, the last move could have been ...a2-a1=B+, ...b2xa1=B+ or ...f6xg5+.

Allow me. White to move, can white checkmate? Only one mating move is legal, and you can tell which. (Protip: Bishops can be promoted... or can they?)

@Remellion: Only dxe6 or hxg6 can be the answer, so the answer must be determined by retrograde analysis. Harder than anything else so far. :)

WIll work on it later.

Notes:

*The last move by black was e5 or g5.

*6 pawns are on the board for white. # of captures=4 (c->d, e->f, f->g->h) at minimum.

Now, assume that the most recent move was g5.

This means that an h-pawn must have gone to h8 (no hate). This adds 6 captures (c->d becomes b->c->d, c->d->e->f->g->h). Total captures=10. This makes all of Black's pieces taken by pawns. Consider the d-pawn for black now. How did the d-pawn get captured? Either a piece has reached d7, a contradiction, or the pawn was captured previously. This is a contradiction, as there would need to be more pawn captures (a->b->c->d). Therefore, g5 cannot be the last move.

Therefore, e5 was the latest move and dxe6 was the checkmate.

Move sequence for e5 coming later if I'm too lazy to actually back up my argument.

y2721's reasoning was... almost wrong. It should be as follows: if the last move was ...g7-g5, white made 10 captures with pawns. Black is missing 9 units. Therefore the last move was not ...g7-g5.

@The_King_Fischer: Mate in 1s can be hard. Aside from the "retro" ones (en passant, castling, black-moves-and-white-mates, both sides have mate but it can only be black to move, etc) the regular ones can be plenty difficult, e.g. mine from 2 pages ago? If an FM can find it difficult... well.

Now watch what a real composer can do, compared to my amateurish ones so far.

Leonid Kubbel
White to move and mate in 1.

@Teddyhead: White's previous move (before ...g7-g5 which is now certain) could have been one of f4-f5+, Nf4x?e6+, or Ng5x?e6+. Don't forget uncaptures!

Queen takes on e5 and checkmate