The 75 move rule

[sje]

I'd also bet this was done to help players in speed chess games. Now you don't have to stop and check your score sheet to see if it has really been 50 moves or not. When you hit 75 it is over and going beyond that in a time scramble has no harmful effect, the game is drawn at 75.

Yes, that could be helpful for speed games. But it violates the long held tradition that a mate on the board trumps all other possible game conclusions; this will happen if a player mates after 75 quiet moves -- the mate won't count under the new rule.

For my part, I'm going to ignore the 75 move and five-fold rule because it's okay with me that my programs will always make a draw claim sooner in either situation. Also, FIDE will likely change the rule again in a few years anyway.

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I've thought about petitioning FIDE to replace the three-fold rule with a much simpler rule saying that a single repetition immediately draws the game, just like a stalemate. This would be easier to understand and to enforce, and slightly easier to code.

I'd also change the 50 move rule to apply only in games which do not have a sudden death time control period.

[syzygy]

But it violates the long held tradition that a mate on the board trumps all other possible game conclusions;

Where does that tradition come from? The 50-move rule has been in place for quite a while already.

[bob]

But it violates the long held tradition that a mate on the board trumps all other possible game conclusions;

Where does that tradition come from? The 50-move rule has been in place for quite a while already.

Actually I think the 75 move rule contains the same wording. The thing he is talking about is that a draw can be claimed after both sides have made 50 non-pawn-moves / non-captures. The exception being that if you make 50 such moves, and on my 50th such move I mate you, you can't claim a 50 move draw, the mate on the board takes precedence, even though the 50 move rule is technically satisfied.

[abulmo]

But it violates the long held tradition that a mate on the board trumps all other possible game conclusions;

Where does that tradition come from? The 50-move rule has been in place for quite a while already.

In the FIDE rules of 1928, as an exception to the 50-move rule, a player was allowed to play twice the number of moves of a theoretical win. This rules was modified several times, and disappeared in 1992.

[sje]

But it violates the long held tradition that a mate on the board trumps all other possible game conclusions; this will happen if a player mates after 75 quiet moves -- the mate won't count under the new rule.

My recollection is that mate on the board overrides all other possible game-ending claims including those supported by the clock. The obvious motivation for this rule is to make the TD's job a bit easier.

[syzygy]

But it violates the long held tradition that a mate on the board trumps all other possible game conclusions;

Where does that tradition come from? The 50-move rule has been in place for quite a while already.

Actually I think the 75 move rule contains the same wording. The thing he is talking about is that a draw can be claimed after both sides have made 50 non-pawn-moves / non-captures. The exception being that if you make 50 such moves, and on my 50th such move I mate you, you can't claim a 50 move draw, the mate on the board takes precedence, even though the 50 move rule is technically satisfied.

I now realise you are right (in this particular case ). I didn't think this is what he meant because, as you say, the 75-move rule has the exact same wording. However, he responded to what you wrote ("the game is drawn at 75") and that, taken literally, would indeed have violated the "tradition" that an actual mate position on the board trumps all other possible game conclusions.

I guess we all agree with this (limited) tradition. (What I thought he meant was that the side having a forced mate-in-N on the board should be allowed to win the game whatever the value of N. This was not true even when there were no known endgames taking move than 50 moves, as even KBNK endgames could easily end in a draw in practical play despite the board position always being a "forced mate-in-N".)

[Chessqueen]

The 75 move rule was apparently instituted by FIDE in mid 2014. Has anyone incorporated it in their chess program?

From the Laws of Chess http://www.fide.com/fide/handbook.html? ... ew=article

9.6

If one or both of the following occur(s) then the game is drawn:

a. the same position has appeared, as in 9.2b, for at least five consecutive alternate moves by each player.
b. any consecutive series of 75 moves have been completed by each player without the movement of any pawn and without any capture. If the last move resulted in checkmate, that shall take precedence.

Why do we still have to use the 50 moves rule when most mate can be found up to 75 moves by Engines that are above 3200