Argh!
The pawn on a7 must have come from f2 along the g1-a7 diagonal. That means five captures of Black pieces on dark squares - the queen, a rook, two knights, and a pawn. But the only place to take a pawn seems to be on a7. But if that's true then how could Black's dark-squared bishop arrive at b8? The remaining Black piece, the light-squared bishop, must have perished on b3 without taking a piece.
White has lost two pieces - the bishops. The black pawn on f4 must have come from h7 first taking the light-squared bishop on g6, followed by g6-g5, then capturing the dark-squared bishop on f4.
I think the goal must be to prove that White's last move was Rf6-g6 followed by Black's pawn move f7-f5. This would allow 1. gxf6+ Kf5 2. Rg5+ Ke4 3. Qg6+ Kd4 4. Qd3#.
Originally posted by Green PaladinYou mean to tell me that that solution which I proposed in jest (PxP e.p) is the actual answer?
I think the goal must be to prove that White's last move was Rf6-g6 followed by Black's pawn move f7-f5. This would allow 1. gxf6+ Kf5 2. Rg5+ Ke4 3. Qg6+ Kd4 4. Qd3#.
I dont know who I want hate more. Myself or SwissGambit!
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Originally posted by Tiwaking
You mean to tell me that that solution which I proposed in jest (PxP e.p) is the actual answer?
I dont know who I want hate more. Myself or SwissGambit!
I cant get it in any less than four moves. There just doesnt seem to be any way to do it.
I don't think the 'mate in four' stipulation can be satisfied without the en passant capture. The real question is how is en passant possible?
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Originally posted by TiwakingThat's like seeing a normal mate in 3 with no retro play, guessing "1.Qa3!" and getting lucky.
You mean to tell me that that solution which I proposed in jest (PxP e.p) is the actual answer?
I dont know who I want hate more. Myself or SwissGambit!
You've provided the right answer, but haven't done the proper analysis. For some people, this is all the satisfaction they need out of a puzzle.
You may refer to Green Paladin's post for an example of how to go about proving Black's last move was ...f7-f5.
Originally posted by Green PaladinThis analysis is right on the money. There is just one thing missing.
Argh!
The pawn on a7 must have come from f2 along the g1-a7 diagonal. That means five captures of Black pieces on dark squares - the queen, a rook, two knights, and a pawn. But the only place to take a pawn seems to be on a7. But if that's true then how could Black's dark-squared bishop arrive at b8? The remaining Black piece, the light-squared bis ...[text shortened]... d by Black's pawn move f7-f5. This would allow 1. gxf6+ Kf5 2. Rg5+ Ke4 3. Qg6+ Kd4 4. Qd3#.
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Originally posted by SwissGambitMore argh!
This analysis is right on the money. There is just one thing missing.
I thought I was on to something... Black's a-pawn promoted before finding its way onto the g1-a7 diagonal. This solves the dilemma with the a7 pawn and the b8 bishop.
But this is impossible as the knight on a1 has to arrive via b3 before the pawn settles there; and the a-file has to be opened before the pawn can promote. This means the promotion square is occupied by the white knight. Nor can the pawn jump files as the captured White pieces have been accounted for.
Another reason this doesn't work is that the pawn on b6 has to move after the white pawn has arrived on a7 but before the light-squared bishop can leave its initial square.
Anyone got any ideas?
Originally posted by Green PaladinWhich pawn came from a2?
More argh!
I thought I was on to something... Black's a-pawn promoted before finding its way onto the g1-a7 diagonal. This solves the dilemma with the a7 pawn and the b8 bishop.
But this is impossible as the knight on a1 has to arrive via b3 before the pawn settles there; and the a-file has to be opened before the pawn can promote. This means t ...[text shortened]... but before the light-squared bishop can leave its initial square.
Anyone got any ideas?
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Originally posted by SwissGambitOk, it has to be a capture on a light-square so that rules out a3xb4. It seems that a2xb3 followed by b3-b4 allows the knight the necessary access to b3 on its way to a1 before b2-b3 seals it in. That's a Band-Aid on that problem.
Which pawn came from a2?
The order of operations:
1. Get the black dark-squared bishop to b8. This requires either a7-a6 or a7-a5.
2. Release the black light-squared bishop with b7-b6. Bring it to b3 where it can be taken with White's a-pawn thereby opening the a-file.
3. Promote the black a-pawn and bring this piece onto the g1-a7 diagonal where it can be snapped up by the white f-pawn.
All very well and good until I notice the pawn on b6 blocking the white pawn's path to a7!
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Originally posted by Green PaladinHmm. Yes, an impasse. I see the problem now.
Ok, it has to be a capture on a light-square so that rules out a3xb4. It seems that a2xb3 followed by b3-b4 allows the knight the necessary access to b3 on its way to a1 before b2-b3 seals it in. That's a Band-Aid on that problem.
The order of operations:
1. Get the black dark-squared bishop to b8. This requires either a7-a6 or a7-a5.
2. Relea ...[text shortened]...
All very well and good until I notice the pawn on b6 blocking the white pawn's path to a7!
Your earlier post that I called 'right on the money' in fact has a subtle error in it. Find the mistaken assumption, and the impasse will be resolved.
Originally posted by SwissGambitThe pawn.
This statement is false. Why?
Black's a7 pawn can't remain on that square and give the dark-squared bishop access to b8. And the bishop must get to b8 before the white pawn gets to a7. So the a7 pawn can't participate in the white f-pawn's diagonal advance. This led me to think that it (the a7 pawn) must promote and then return as a new incarnation to the g1-a7 diagonal.