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Jesper Norgaard
02-11-2009, 04:12 PM
Here is a little exercise for the little grey cells. In fact it is not mine - I will reveal who are the author(s) later.

kB6/2K5/8/2N5/8/8/8/8 w - - 0 1

It is white to move, and suddenly black's mobile phone rings

(question 1) Is it in fact a legal position (with white to move)?

(question 2) When the arbiter is brought in, what should be the result of the game?

Hint: a bit of retrograde analysis might reveal the answer. I think I would have failed, unfortunately saw the "intended answer" before realizing how difficult it was. Note that it did not actually happen in an OTB game - but it could have, and it just might be in the next arbiters exam, who knows? :lol:

Desmond
02-11-2009, 04:26 PM
I think it could be a legal position if we take it that the bishop is the result of a pawn promotion last move.

I expect the result would be 0-.5

Kevin Bonham
02-11-2009, 04:36 PM
Answers in white.


(question 1) Is it in fact a legal position (with white to move)?

Initially I thought no, but I was wrong. It is a legal position. Put black king on a7, white pawn on a5, black queen on b1, white king and knight where they are; an obviously legally reachable position. Black to move plays Qb1-b6+. White plays a5xb6+. Black plays Ka7-a8. White plays b7+. Black plays Ka8-a7. White plays b8=B+. Black plays Ka7-a8. Position reached.


(question 2) When the arbiter is brought in, what should be the result of the game?

Draw by dead position.

Jesper Norgaard
02-11-2009, 04:37 PM
Good try Boris, but let's see if there are any more entries!

My line of thinking was the same as yours, so I would probably have failed too. Can't really know if I would have solved it, since I snitched up the solution without really giving it an effort to solve it myself.

Kevin Bonham
02-11-2009, 04:39 PM
I think I got question 2 wrong twice within a few minutes (right answer for wrong reason then wrong answer for wrong reason) but believe what I have edited my answer to to be correct.

Garvinator
02-11-2009, 04:49 PM
Draw.

It is white to move, and suddenly black's mobile phone rings. I think some previous respondents may have missed it is black's mobile that rings, not whites.

It is white to move in this position, we have determined that we can get to this position legally, but in this position white can not checkmate black with any series of legal moves.

5.2 b. The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was legal.

There is only one legal bishop move Ba7 and that forces Kxa7, insufficient material draw.

Any knight move produces stalemate and any King move results in either stalemate or insufficient material.

Jesper Norgaard
02-11-2009, 04:57 PM
Answers in white.
Yes but now in black. You guys are really quick, so I will have to reveal my hand :P


Initially I thought no, but I was wrong. It is a legal position. Put black king on a7, white pawn on a5, black queen on b1, white king and knight where they are; an obviously legally reachable position. Black to move plays Qb1-b6+. White plays a5xb6+. Black plays Ka7-a8. White plays b7+. Black plays Ka8-a7. White plays b8=B+. Black plays Ka7-a8. Position reached.
Actually you don't need that much ingenuity, just white pawn on b5, black last played Ka8-a7, now b6+ etc. An obviously legally reachable position you say? There is the problem. See below.


Draw by dead position. YES!! That is the solution of the result. The dead position was reached before the mobile phone rang, thus it was a draw and the game ended before that incident. But was it a legally reachable position? In fact not. According to the FIDE rules, when white plays b8=B+ the position is already dead, and thus the move Ka7-a8 was not a part of the game, which the arbiter should inform the players. I admit it is cheaky. The original composition was from A.G. Buchanan on http://anselan.com/tutorial.html and IM Jens Kristiansen spiced it up with the mobile phone ringing. The situation would have been different if the white knight had not been covering a6 - in that case after b8=B+ black still had the option of playing Ka6, and therefore the move Ka8 would still be part of the game, but ending it in that moment (for instance with Nd8 instead of Nc5).

Kevin Bonham
02-11-2009, 04:57 PM
Draw.

It is white to move, and suddenly black's mobile phone rings. I think some previous respondents may have missed it is black's mobile that rings, not whites.

Actually I think it said white's phone rang originally, and then was edited. But in any case it is immaterial whose phone rang since the game has already ended by dead position.

Jesper Norgaard
02-11-2009, 05:13 PM
I think I got question 2 wrong twice within a few minutes (right answer for wrong reason then wrong answer for wrong reason) but believe what I have edited my answer to to be correct.
You have an advantage as admin there Kevin, when you goofup and write something wrong you can just edit and nobody will know, when us mere mortals goofup and edit our post, it is revealed with the small letters below ... :lol:

Jesper Norgaard
02-11-2009, 05:21 PM
Actually I think it said white's phone rang originally, and then was edited. But in any case it is immaterial whose phone rang since the game has already ended by dead position.
Exactly. I originally made it white's phone without putting much attention, but then saw Jens Kristiansen had made it black's phone, and I realized this would give an extra trap - maybe some would think white actually wins because he has mating material (which to many people's surprise is not part of the FIDE rules, nor are there perpetual check or three-fold repetition of the moves etc.). As I understand it sufficient mating material was never part of the rules, but insufficient mating material was (including bishop each on same-color squares).

Kevin Bonham
02-11-2009, 06:02 PM
You have an advantage as admin there Kevin, when you goofup and write something wrong you can just edit and nobody will know, when us mere mortals goofup and edit our post, it is revealed with the small letters below ... :lol:

Actually there is a time window within which an edit is not noted and I think this is the same for all posters. Try posting something then editing it immediately; I don't think you'll get the edit stamp. There are plenty of my posts which show "edited by" because I edited them after that window had expired. If I'm right, the difference is that there is a window beyond which a normal poster cannot edit, but a mod still can (including their own posts).

Basil
02-11-2009, 06:11 PM
Actually there is a time window within which an edit is not noted and I think this is the same for all posters. Try posting something then editing it immediately; I don't think you'll get the edit stamp. There are plenty of my posts which show "edited by" because I edited them after that window had expired. If I'm right, the difference is that there is a window beyond which a normal poster cannot edit, but a mod still can (including their own posts).
Correct on all counts.

Jesper Norgaard
02-11-2009, 06:30 PM
Actually there is a time window within which an edit is not noted and I think this is the same for all posters. Try posting something then editing it immediately; I don't think you'll get the edit stamp.
Confirmed to be true, but the window must be pretty small for practical purposes. In #7 there was 6 minutes between my post and my correction. :D

Bill Gletsos
02-11-2009, 07:28 PM
Confirmed to be true, but the window must be pretty small for practical purposes.You have 2 minutes.