Originally posted by BigDoggProblemI haven't been able to spend a lot of time (yet) on this, but here are a few considerations that others may use to find a solution (or to contradict my observations):
No.
- f7-f6 seems like a good candidate last move to me. Without that, I do not see an easy way back out for the white king
- white is missing two pawns, nothing else. Black's two pawns that have captured didn't take a white pawn. Hence, white promoted two pawns and they got captured. Must be e- and g-pawns
- black has promoted his pawn for a rook (3 rooks). Has to be the g-pawn.
- how did the two g-pawns pass on the g-file? I see two solutions: the white pawn takes something on f7, and then promotes, or the white pawn takes something on the h-file, let's the black pawn pass, and takes something else on the g-file. Since I think the f-pawn moved last in the game, the first option is not available. So, I think both black knights were captured by white's g-pawn (first to the h-file, then back to the g-file)
- still to be analysed: all the other moves, which I believe (hope) are just move order issues (e.g. the white bishops on the a-file).
that's it so far
Originally posted by Mephisto2You're off to a good start. One caveat: wPc3 captured a black Knight, so wPg can't make two captures. This means White must have played gxf7 to promote, so Black may not retract ...f7-f6 for a long while.
I haven't been able to spend a lot of time (yet) on this, but here are a few considerations that others may use to find a solution (or to contradict my observations):
- f7-f6 seems like a good candidate last move to me. Without that, I do not see an easy way back out for the white king
- white is missing two pawns, nothing else. Black's two pawns tha ...[text shortened]... pe) are just move order issues (e.g. the white bishops on the a-file).
that's it so far
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Originally posted by MixoThat's a good intro to retros, but this one is much harder to solve than anything in Smullyan's book.
For puzzles like this (Retrograde Analysis) read "the chess mysteries of Sherlock Holmes" by Raymond Smullyan - nothing to do with the original Holmes stories but he provides a good character for the author to use
Originally posted by BigDoggProblemYes, of course, that was not very bright of me. Well, that certainly doesn't make the unraveling easier....
You're off to a good start. One caveat: wPc3 captured a black Knight, so wPg can't make two captures. This means White must have played gxf7 to promote, so Black may not retract ...f7-f6 for a long while.
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Originally posted by BigDoggProblemBut you must tell who moved last? Black or white? I guess black must have moved last.
T. Volet and P. Wassong
StrateGems 2001
[fen]Nrbb4/qprp3p/PpQK1p1P/RRpp4/Brk2P2/B1P5/1PP5/1N6[/fen]
Release the position
(3 Black Rooks)
(Release the position: Prove that the position is legal, by taking back moves until you reach a position in the past that is obviously legal.)