Now Try This...

I would like to post a puzzle, but I will have to make up the piece placements because I don't remember the exact positions of every piece on the board at the time.

I can just put the important pieces; however, I will have to study how to make a board on here to start with and what not.

P.S. Maybe GreenPawn can help me do it

Just post

White: Ke8, Rg4, Bh2

Black: Ka1, Kg2, pawns on b6 and c6

or where ever the pieces go. Someone will do the diagram for you.

Hi SG.

"The white pawn could have taken (b6xc7), and then the black b-pawn could have stepped forward twice (...b6 and ...b5)."




No. There have only been 3 Black units lost.
One is the light squared Black Bishop (taken on e4 by the f-pawn) the pawn
advanced one square and took Knights on d6 and c7 (I think).

Originally posted by greenpawn34
Hi SG.

"The white pawn could have taken (b6xc7), and then the black b-pawn could have stepped forward twice (...b6 and ...b5)."


[fen]8/p1Pp1ppN/R1p4p/Pp4P1/7p/2PP2P1/kqQrP3/rNbB4 w - - 0 1[/fen]

No. There have only been 3 Black units lost.
One is the light squared Black Bishop (taken on e4 by the f-pawn) the pawn
advanced one square and took Knights on d6 and c7 (I think).

White only needs to make 2 pawn captures: b6xNc7 and f4xNg5, for example.

Here's a sequence with wK on c4 showing that b6-b5+ could have been the last move.

....mumble....grumble....mumble....smart ass....mumble....grumble...

Why is nobody else trying this?

Is it because you cannot use a computer to solve it?
(have you noticed that S.G? Post a mate in 3 - dozens of answers
something where a box cannot be used - silence.....or maybe they are
just enjoying watching me screwing it up.)

Black forgot he play en passant!....solv'd.

(Off to work be back later.)

Some observations, none of which seem to quite lead to a solution:

1) 3 white units captured: R, B and P.
These were captured by the black e7 pawn on f6, g5 and h4 (white pawn was captured on h4).

2) 3 black units captured: B, N and N.
These were captured on c7 (bxc7), g5 (fxg5) and ?
2a) If last black move was b7-b5, then his light squared bishop was captured on c8.
2b) If last black move was b6-b5 then we don't know where light squared bishop was captured.

3) Black pawn on h4 got there before white pawn on g5.

4) White rook on a6 got there via b6 and before the white pawn got to b6 (or even b5).

It almost seems like it would be more likely to be provable that the black light-squared bishop _didn't_ get captured on c8, hence black pawn moved to b6 at some stage (to allow the bishop to move and subsequently be captured elsewhere).

Originally posted by greenpawn34
....mumble....grumble....mumble....smart ass....mumble....grumble...

Why is nobody else trying this?

Is it because you cannot use a computer to solve it?
(have you noticed that S.G? Post a mate in 3 - dozens of answers
something where a box cannot be used - silence.....or maybe they are
just enjoying watching me screwing it up.)

Black forgot he play en passant!....solv'd.

(Off to work be back later.)

All the other problemists left the building a long time ago! That's why you are not getting any help.

Anyone who has run a solving tourney knows that problems like these are useful for embarrassing cheats. 🙂

In order for b7-b5 to be the last move, black's light squared bishop must never have moved and been captured on his home square. I'm not sure this is useful.

Edit: data fly already pointed that out.

Perhaps there's a clue in the FEN itself:
8/p1Pp1ppN/R1p4p/Pp4P1/7p/2PP2P1/kqQrP3/rNbB4 w - - 0 1

The "half move counter", i.e. the number of half moves since the last pawn move or capture, is zero. So Black's last move was either a pawn move or a capture.

Edit. Actually that's pretty bloody obvious since Black's last move was either b7-b5 or b7-b6!

Originally posted by Data Fly
Perhaps there's a clue in the FEN itself:
8/p1Pp1ppN/R1p4p/Pp4P1/7p/2PP2P1/kqQrP3/rNbB4 w - - 0 1

The "half move counter", i.e. the number of half moves since the last pawn move or capture, is zero. So Black's last move was either a pawn move or a capture.

No; I never fill out the FEN with the actual information. That would give clues that I don't want to give.

OK. With the white king on c5.



The last Black move cannot have been b6-b5, because white would have been in check.

c7-c6 and h7-h6 are out because there are white units on c7 and h7.

It may have been Qb2, blocking a check. But where did the black queen come from? Clearly not a3 or b4, as white would have been in check himself. So Qb3-b2 is the only possibility. But this itself is impossible because the white queen has no legal way to play Qc2+ - it can't have come from b2 itself and none of white's pieces can have moved from b2 giving a discovered check. Hence black's last move was not Qb2.

This leaves b7-b5 as being the only possible last move for Black, and then White has axb6#.

Thus the solution is that the White king has to be on c5, not c4, as with it on c4 it is not possible to prove that Black's last move was b7-b5 (and it's quite easy to construct a series of moves where this is not the case).

Conversely, with the white king on a4:

I guess the intention is to show that Black's move prior to b7-b5 or b6-b5 cannot have been Qb6-b2, blocking a check, because the white had no way to get to c2 without black being in check already.

However I'm struggling to prove that this sequence is not legal:

Originally posted by Data Fly
OK. With the white king on c5.

[fen]8/p1Pp1ppN/R1p4p/PpK3P1/7p/2PP2P1/kqQrP3/rNbB4 w - - 0 1[/fen]

The last Black move cannot have been b6-b5, because white would have been in check.

c7-c6 and h7-h6 are out because there are white units on c7 and h7.

It may have been Qb2, blocking a check. But where did the black queen come from? Clearly not a3 ...[text shortened]... move was b7-b5 (and it's quite easy to construct a series of moves where this is not the case).

So far, so good. There is only one possibility you did not consider. What if bQ just captured something on b2?

Originally posted by Data Fly

However I'm struggling to prove that this sequence is not legal:

It's legal. However, it is not the only possible last move. Convention is that white may only play e.p. if it can be proved that black's last move was b7-b5.