A Chess paradox

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andrew martin

A Chess paradox

Post by andrew martin » Thu Nov 24, 2011 8:39 pm

During the hot afternoon today I came across the following position and would be interested to hear the opinion of others:

White : Kh3, Bishops, f1,a7, Pawns e5,b6
Black: Kb7, Bishops, c8,g3, Pawns a6, d7, h4

Composed by Assiac 1951


White to move plays 1 Bg2 check answered by 1...d5 MATE

Except White argues that because he can play 2 exd6 en passent the pawn never reached d5 in the first place. Black has therefore played an illegal move and is unable to block the check.

Comments?

Paul Cooksey

Re: A Chess paradox

Post by Paul Cooksey » Thu Nov 24, 2011 9:04 pm

Checkmate ends the game!
Last edited by Paul Cooksey on Thu Nov 24, 2011 9:09 pm, edited 1 time in total.

Jon D'Souza-Eva

Re: A Chess paradox

Post by Jon D'Souza-Eva » Thu Nov 24, 2011 9:09 pm

White can play 2. e6, so it isn't mate. With the e5 pawn on c5 it works.

Mike Truran
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Re: A Chess paradox

Post by Mike Truran » Thu Nov 24, 2011 9:16 pm

In Heinrich Fraenkel's original article the pawn is indeed on c5. I suspect Fraenkel's own words are perfectly adequate:

"The two professors went on arguing for quite a while, until some higher authority adjudicated the position as a win for Black. Even then, Professor White, I am afraid, was far from satisfied. But that does not disprove the fairness of our rules; it merely proves that the Professor, far from being a master at chess, would seem to be a master at sophistry rather than at logic."

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IM Jack Rudd
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Re: A Chess paradox

Post by IM Jack Rudd » Thu Nov 24, 2011 10:01 pm

This is not as good as Pandin's Paradox.

Alex Holowczak
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Re: A Chess paradox

Post by Alex Holowczak » Thu Nov 24, 2011 11:53 pm

Paul Cooksey wrote:Checkmate ends the game!
Not quite. Checkmate immediately ends the game, only if the move delivering checkmate was legal. d5 is a legal move, and thus it is a win for black. 8)

Geoff Chandler
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Re: A Chess paradox

Post by Geoff Chandler » Fri Nov 25, 2011 1:32 am

Staying with this position.



White to play is in check. He must get out of check.
As pxp ep does not achieve this then pxp ep. is illegal.
(Infact it would leave both Kings in check.)

The argument that the pawn never reaches d5 is defunct.
EP is an unoforced privilage. The pawn does indeed reach d5.
Under nornal circumstances White could if he chooses play 2.pxp ep
but he MUST get of check and ep does not do this.

In Passing:

The Queen is the most powerful piece on the board.
What is the one thing a Queen cannot do that every other piece,
inlcuding the pawns, can do? (a good question for juniors that one.)

(someone will post the answer - if you don't know it think about it before you peek.)
Last edited by Geoff Chandler on Fri Nov 25, 2011 12:30 pm, edited 1 time in total.

andrew martin

Re: A Chess paradox

Post by andrew martin » Fri Nov 25, 2011 9:05 am

Interesting point about the pawn being on c5 in the original position. The diagram with the pawn on e5 was quoted faithfully from ' The Joys of Chess' by Christian Hesse (New in Chess 2011), an otherwise excellent book.

Jonathan Berry
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Re: A Chess paradox

Post by Jonathan Berry » Fri Nov 25, 2011 9:33 am

Up to 1980 or so, the solution, interpreting literally the FIDE Laws of Chess of the day, would be Bf1-d5 mate. Gosh, it took a long time to get the rules changed on that one!

Mike Truran
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Re: A Chess paradox

Post by Mike Truran » Fri Nov 25, 2011 9:50 am

It was published (I think for the first time) in 'Chess Treasury of the Air', a compilation of the best of the series of chess articles broadcast on the radio between 1958 and 1965. It does seem odd that just copying a diagram from the first book would have led to the misplaced pawn.

Happy days. It's hard to imagine in these fallow days for chess broadcasting that there was was once a programme that ran for the best part of six years.

I hasten to add that I am not of such venerable years that I was able to listen to the originals.

andrew martin

Re: A Chess paradox

Post by andrew martin » Fri Nov 25, 2011 9:52 am

Of course, had Stewart Reuben been consulted, this position would never have occurred in the first place.

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John Clarke
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Re: A Chess paradox

Post by John Clarke » Fri Nov 25, 2011 10:59 am

The position, with the P at c5, not e5, first appeared on p169 of Assiac's "Adventure in Chess", published 1951.

His final comment there reads: " ... a win for Black. No doubt, from what we all know about the rules of Chess, we must agree with that ruling, but I am not very happy about it. Somehow I feel the excitable logician did have an arguable case, to say the least." Bit of a contrast to his later one!

The book was reissued in a 1960 Dover edition as "The Pleasures of Chess", the change of title possibly intended to complement the author's "The Delights of Chess, which came out that year. (But the original title is still referred to in the final section on p180!)
"The chess-board is the world ..... the player on the other side is hidden from us ..... he never overlooks a mistake, or makes the smallest allowance for ignorance."
(He doesn't let you resign and start again, either.)

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Re: A Chess paradox

Post by Geoff Chandler » Fri Nov 25, 2011 12:43 pm

The Queen is the most powerful piece on the board.
What is the one thing a Queen cannot do that every other piece,
inlcuding the pawns, can do?

It can never be the piece that actually moves to give a discovered check.
(else it would already be giving check.)

E Michael White
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Re: A Chess paradox

Post by E Michael White » Fri Nov 25, 2011 12:50 pm

Right and wrong

The Queen is the only piece that can be part of a double check where both checking pieces are the same type ie 2 queens giving double check, without promoting a pawn as part of that move. I guess thats correct but dont have a board here.

Geoff Chandler
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Re: A Chess paradox

Post by Geoff Chandler » Fri Nov 25, 2011 12:58 pm



You can replace the c4 pawn with any piece except another Rook
or Queen and they can move to give a double check.

Again you can replace the f2 Rook with any piece except another
Bishop or Queen to give discovered check.

And as the Queen is a Brook (Bishop & Rook Combined) then
she cannot be the piece that sits on c4 or f2.

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