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19 Jul 11
Right now, there are two kinds of moves which reset the 50 move rule counter. These are captures and pawn moves. The reason for this choice is that those are the only two moves which cannot be undone, so after those moves, and only those moves, do we know for certain that the game is still progressing. Right?
Wrong.
There is another kind of move which can never be undone. Granted, it is highly unlikely that these moves are made in circumstances in which the 50 move rule could be affected, but it is conceivable, and therefore these moves should be added to the rule: the first move of any rook, so long as its king has not moved, or the first move of either king, so long as at least one of its rooks has not moved.
Now let the nit-picking begin.
Richard
19 Jul 11
1 edit
Originally posted by Shallow BlueHere's one nit-pick: a capture is no guarantee that progress is being made.
Right now, there are two kinds of moves which reset the 50 move rule counter. These are captures and pawn moves. The reason for this choice is that those are the only two moves which cannot be undone, so after those moves, and only those moves, do we know for certain that the game is still progressing. Right?
Wrong.
There is another kind of move w ...[text shortened]... so long as at least one of its rooks has not moved.
Now let the nit-picking begin.
Richard
In fact, there are some captures that are not legal specifically because no progress is being made.
White is not permitted to play 1.Kxa1 here. The position is an immediate draw because of a FIDE rule that states the game is drawn if there is zero possibility of checkmate, even against the most unskilled counterplay. This position meets the criteria before the Queen is captured.
20 Jul 11
Originally posted by SwissGambitpermit me a nit-pick;
Here's one nit-pick: a capture is no guarantee that progress is being made.
In fact, there are some captures that are not legal specifically because no progress is being made.
[fen]8/1k6/8/p1p1p1p1/P1P1P1P1/8/2B5/qK6 w - - 0 1[/fen]
White is not permitted to play 1.Kxa1 here. The position is an immediate draw because of a FIDE rule that states t ...[text shortened]... st unskilled counterplay. This position meets the criteria before the Queen is captured.
white is permitted to capture. in fact white is forced to capture.
20 Jul 11
Originally posted by SwissGambitYes, I see.
Moves that can't be undone indicate that the position is changing in a permanent way.
Widening the debate, are there any situations where computers have now shown that a win is possible in some specific endings where more than 50 moves are required?
If so, should not the 50 move rule be amended to, say, an 80 move rule for that particular ending?
20 Jul 11
Originally posted by greenerpawnThey did that without computers having anything to do with it.Don't recall which ending(s),think Troitsky had something to do with it.
Yes, I see.
Widening the debate, are there any situations where computers have now shown that a win is possible in some specific endings where more than 50 moves are required?
If so, should not the 50 move rule be amended to, say, an 80 move rule for that particular ending?
Later they went back to the old rule.Not sure why,I think so many exceptions started popping up that it got too complicated.
As for computers.They're currently at 'white wins in 517',and it's actually mate in 529.
http://timkr.home.xs4all.nl/chess2/diary16txt.htm
Look at n°316
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20 Jul 11
Originally posted by tortenHowever, if you lose the right to castle, you can no longer castle in one move. That's one move which will never be possible again in that game. Hence, irreversible.
No irreversible change.
You can still castle,or uncastle,by hand.
Richard
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20 Jul 11
Originally posted by sundown316All normal moves can be undone simply by making the opposite move. Moving your queen from a4 to b3 can be undone by, the next move, moving it from b3 to a4. You could move your queen through all squares, and your opponent could be moving his through them all in a different order. You could easily avoid the 3-repetitions rule by moving in irregular patterns. The 50-move rule exists to avoid such a situation.
Since when can any move,except an illegal one,be undone?
Even moving out of check can be undone if your opponent first moves his checking piece back to where it was. The only moves which cannot be undone are those which permanently remove an option from that game. These moves are pawn moves, because a pawn may not move backwards; captures, because a captured piece can not reappear on the board (except through promotion, but that's a pawn move!); and, as I am arguing in this thread, moves which make castling impossible (which, as Ponderable so astutely noticed, includes all castlings themselves).
Richard