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MatPlus.Net Forum Retro/Math Dear Mordehai Shaham,...

### Dear Mordehai Shaham,...

...I recently found this position by you.

(= 8+13 )

FEN 2b1brb1/1pPn1k1n/3P1P1p/3PpKpP/4P1Pp/7p/8/8

White to move, what is the outcome?
2nd hm, Israel Retrograde Tourney 1966-1971

I disagree with your solution. You thought:

White wins: As black's last move must have been e7-e5 or g7-g5, white mates by 1.dxe6# or hxg6#

Draw: To capture en passant, the possibility of en passant capture must be proven. It can neither be proven that black played e7-e5 nor that he played g7-g5, thus stalemate.

White loses: Since white has a legal move, but can't execute it (see draw) he'll eventually overstep the time limit and lose.

First, I don't know if this was possible at that time. Today it would be a draw if white overstepped the time limit here. However, I would even break the rules if I were a judge and would give the full point to white since this is how the game would end even at worst play.

I only can agree to a white win. It is in my opinion not necessary to prove what exactly is the next move, as long as it will be a checkmate.

The whole thing reminds me to a #2 I've seen once, where white either can take en passant or black can't castle but nothing of it can be proven in itself. See number 3 on http://www.bcps.knightsfield.co.uk/retros.html

Best regards,
Siegfried Hornecker

Maybe someone can forward this to Mr. Shaham if he's still alive?

Some writer in a popular book (which I already forgot :-)
shot a hole into this logic decades ago: If White could
overstep the time, it was a tournament game and he could
as well look at his sheet for Blacks last move!

Hauke

But not in a blitz game...

*push* Did anyone inform Mr. Shaham of this discussion? I sadly don't know how to contact him and would like to hear his opinion.

(5) Posted by Uri Avner [Saturday, Mar 1, 2008 02:45]

I hope to meet Mordehai Shaham (better known as "Motti") in Tel Aviv tomorrow (March 2nd) at the monthly meeting of Israeli composers. Have no worry; the man is alive and kicking (at least as a lawyer). I'll tell him about the discussion and ask for his legal opinion :)

Clearly the position by Motti is a teaser, and should be taken as such.

Otherwise:

* This is a composition, by Motti Shaham, and not a game. Thus, any consideration on what would happen in a match (time limit, judge) is meaningless.

* Indeed one cannot prove what was the last move. But we clearly know that the last move was either of the possible two. So an "if" solution exist.

Thus, I agree with Siegfried on the solution.

Paz