What are the parameters of the 50 move rule?

if noone takes a piece in 50 moves then it's a stale mate

If no pieces are captured and no pawns are moved for 50 moves, then the game is a draw. (It's not a stalemate, that's a different kind of draw.)

ty

Has anyone ever come across an example of this rule being applied?  I seem to remember finding, many years ago, one game that had been drawn many years before because of the 50 move rule; but I'm much too old now to remember what I think I knew.

It applies to certain endgames like 2 rooks + bishop vs 2 rooks, where the side with the bishop would win, but it takes more than 50 moves to checkmate.

 I once was forced to apply this rule when my opponent in an OTB game refused to accept the draw in a position that was clearly drawn.

It can come into play in K+B+N vs K endgames if the player with the stronger side is unsure of the winning technique.  I had a stand alone chess computer once that would declare a draw when less than 50 moves had been made and no stalemate or 3 fold repitition.  I guess the program had a bug in it.

 

 Correct me if i'm wrong, but wasn't the rule extended to 75 moves for certain endgames such as 2 Bishops VS. a lone king?

Markle wrote:

 

 Correct me if i'm wrong, but wasn't the rule extended to 75 moves for certain endgames such as 2 Bishops VS. a lone king?

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 2 Bishops vs. a lone king should not take 75+ moves to checkmate.

 

 No it shouldn't, but i still think the rule has been changed for certain endgames.

yeah the rule has been changed for some endgame situations mainly because computer know mating techniques that take longer then 50 moves also one side has to claim it or an arbiter declare the draw  because of it otherwise technically theres no reason a game couldn't go on for ever.

 

 Thank you kolechess for confirming that

Here is the FIDE rule:

"9.3

The game is drawn, upon a correct claim by the player having the move, if he writes his move on his scoresheet, and declares to the arbiter his intention to make this move which shall result in the last 50 moves having been made by each player without the movement of any pawn and without any capture, or the last 50 consecutive moves have been made by each player without the movement of any pawn and without any capture."

The use of more than 50 moves for some endings was used for a period and dispensed with.

Markle wrote:

 

 Correct me if i'm wrong, but wasn't the rule extended to 75 moves for certain endgames such as 2 Bishops VS. a lone king?

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That would have been for K+2N v K+P.  I wasn't aware of what GreenLaser said about the 50-move rule covering that ending as well now.

My recollection was that for 2N v P a higher limit was allowed.

 

I've seen the threefold repetition of position (with the same player to move! this is important) invoked a number of times, mostly to the chagrin of the winning player who is trying to manouver his pieces and stumbles into that third repetition totally unwittingly.

A recent game used the 50 move rule. It was Nguyen Ngoc Truong Son-Maxine Vachier Lagrave (they almost need a 50 letter rule), Aeroflot Open 2008. With a rook and bishop against rook the position was drawn after 50 moves even though the better side had mate in two.

TY all very much....I was playing a game last month where the computer would not let us move and we finally discovered a "peasseant" (sp?) had occurred

Yes, the rule has been changed a few times over the last hundred years, as it became clear that there were several scenarios where mate may not be forced in less than 50 moves.

At one point it was 100 moves I think, then it changed so that only when certain combinations of material remained would it be 100 moves, otherwise 50 would stil apply. But sometime in the last 15 years I think, it changed back to the standard 50 moves: no pawn move or capture in 50 (1 ply) moves and the game is declared a draw. Even where there is pending mate in 2.

It's a little sad that the 50 move rule still exists.  It was clearly thought up because a player did not deserve the win who did not know how to win, and 50 moves was at the time thought more than enough for any situation.  But when a game is called drawn even though the position is obviously mate in 2, then something is wrong...