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I’ve decided to do something a little different this time. I’m going to give you nearly all of the moves of one side, and must figure out the rest of the moves of the other side. Variations are allowed, as always, but the end result must be the same. I am sorry in advance of this is not possible. I just wanted to try something new!

Number Of Moves: 24

Checkmater: Black

Given Game (Regular Chess Notation):

  1. ? c5
  2. ? c4
  3. ? b5
  4. ? b4
  5. ? e5
  6. ? f5
  7. ? Bc5
  8. ? e4
  9. ? f4
  10. ?d5
  11. ? f3
  12. ? Bf5
  13. ? Be4
  14. ? g5
  15. ? g4+
  16. ? g3
  17. ? Qh4+
  18. ? Qf4+
  19. ? Nd7+
  20. ? ?
  21. ? ?
  22. ? ?
  23. ? ?
  24. ? Nf3# *

Cryptic Clue #1: This is black’s 19th matricide. (This is a pun!)

Cryptic Clue #2: How would you feel if your closest friends betrayed you and let you die?

Cryptic Clue #3: Assume that all moves are pawn moves unless it can be proven if it is stated as such.

Task: To use retrograde analysis and give an answer with all of the question marked moves solved, along with reasons for each move. A simple PGN post shall suffice. A link is optional.

As always, may the odds ever be in your favor!

This one will be lots of fun, I say!

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Here is the solution. The explanation follows.

Here is another, where Cryptic Clue n°1 is understood as

Queen-side (pun with matri-cide) castling by Black.

There is plenty of freedom in this puzzle, as shown by these two examples.

After move 14, the situation is (up to White's moves and possibly captured Black pieces)

enter image description here

and in this position,

g4 comes with check. There can't be any discoveries, so the White King is either in h3 or f3

PROOF THAT h3 IS IMPOSSIBLE

16. ... g3 follows, so the pawn wasn't captured, so the King moved, and it didn't move to g3 or g4. But a few moves later, we have 19. ... Nd7+ meaning that the King is then either in f6, e5 or c5. If the King is in h3 when g4+ is played, then moving to the second row makes it too far for him to reach f6, e5 or c5 in time (all Black moves would need to be King moves and the only target square would be e5, and this is impossible due to 18. ... Qf4+). Therefore g4+ is followed by Kh4, meaning that a white piece protects the King from check by the Queen. But then there is no way 17. ... Qh4+ can happen: the whole diagonal would need to be free for the Queen to move, so move 17 by White would need to remove the King from h4 and free the Queen's diagonal.

Partial conclusion:

The Bishop in e4 was captured some time earlier (as well as the Black e pawn to allow the Bishop there in the first place).

WHERE IS THE WHITE KING AFTER MOVE 19.

It can only be in f6, e5 or c5. But c5 is impossible due to the sequence of checks by the Queen. f6 is possible only if there is a white piece at f5 AND the Knight at g8 was captured. It is not really in White's interest to spend time capturing Black pieces, given that Black is to deliver checkmate at the end. So e5 seems more likely. Note that e5 implies that the Queen gets captured at move 19, which is not in our interest either but coincides with Cryptic Clue n°1.

WHAT THE FINAL POSITION TELLS US

We know that Nf3 is mate, which means that the White e and g pawn, as well as the Ng1 are gone. So is the white Queen, consequently. One of the pawns can conveniently serve the purpose of capturing f3 and the Bishop e4. The Queen, on the other hand, can serve the purpose of letting the Black rooks free, so that they can help checkmating in the end (otherwise Black is poor in material).

CRYPTIC CLUES

N°1:

White captures the B Queen at move 19, but also there are exactly 19 moves where White offers their Queen to be captured.

N°2:

The King's closest friends are the Queen and Light square Bishop, both of which are in a position to capture Black's mating material (the Rook at a6) but don't interfere.

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    $\begingroup$ @RewanDemontay The first few of these seemed self-confirming and uniquely solvable, with the "clues" giving some pointers on which way to proceed. With the most recent puzzles (Foxhole Failures, Chess Notations 2.5 and 3), though, it seems like there are multiple ways to fit a game to the supplied move list, and the only thing that makes some (all but one?) of those games not the answer is that they somehow don't fit the Cryptic Clue(s), even when the answerer thinks they do.... which puts these recent puzzles dangerously close to "guess what I'm thinking of?" territory. $\endgroup$ – Rubio♦ Apr 6 '19 at 20:56
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    $\begingroup$ @RewanDemontay Having the solution and seeing how it satisfies the supplied clue(s) is a very different thing from having to figure out which approach to take and which solution will be correct based on only the cryptically obscure clue(s) included in the puzzle. Puzzles need to be forward-solvable from the information provided, not simply have answers that are confirmable after the fact. Are you sure these puzzles give enough information to meaningfully solve them without "being inside your head"? $\endgroup$ – Rubio♦ Apr 6 '19 at 20:56
  • $\begingroup$ @Rubio It does throw you off a little bit when you see that the moves leave much more freedom than you would expect. Perhaps it should be emphasized that the main point of the puzzle is to solve the cryptic clues - but that would make the puzzles a little bit less attractive, at least to me. $\endgroup$ – Arnaud Mortier Apr 7 '19 at 8:45
  • $\begingroup$ @RewanDemontay so, is CC1 related to rot13(pnfgyvat Dhrrafvqr? Nf va 19-gu praghel pnfgyrf, naq zngev-pvqr = dhrra-fvqr)? $\endgroup$ – Arnaud Mortier Apr 7 '19 at 8:47

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