67 votes
Accepted

Why is there a 50-move rule and a 75-move rule?

From the FIDE Laws of Chess: 50-move rule: 9.3 The game is drawn, upon a correct claim by a player having the move, if: (...) the last 50 moves by each player have been completed without the ...
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  • 5,774
19 votes
Accepted

A 50-move-rule claim turned out to be incorrect - can the arbiter punish me?

Yes According to the FIDE Laws of Chess 9.5.3 If the claim is found to be incorrect, the arbiter shall add two minutes to the opponent’s remaining thinking time. Then the game shall continue. If the ...
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  • 75.7k
18 votes
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Identify a problem where a potentially winning move draws because of the 50 move rule

There are dozens of problems that illustrate a potential winning moves that instead leads to a draw because of the 50 move rule. One example is the following mate in four published by Léon Loewenton ...
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  • 713
15 votes

Does checkmate over ride 50-move rule?

Checkmate overrides the 50 move rule. Fide Handbook Article 9.3: The game is drawn, upon a correct claim by a player having the move, if: a. he writes his move, which cannot be changed, on ...
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  • 3,425
13 votes
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Is it OK to look at the list of played moves during the game to determine the status of the 50 move rule?

The rules for this and how it works are spelled out in articles 9.3, 9.4 and 9.5 of the FIDE Laws of Chess. They don't mention whether or not you are allowed to check your scoresheet to do this ...
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  • 75.7k
12 votes
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Is the 50-move rule ever used in grandmaster games?

Yes, sometimes the 50-move rule comes up in grandmaster play. One recent example that comes to mind was the game Ushenina-Girya (Geneva 2013), in which the reigning women's world champion failed to ...
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  • 23.1k
12 votes

Why is there a 50-move rule and a 75-move rule?

Although the responses all were intended to answer the question, they all fell slightly short. The 75-move rule was implemented so that an arbiter could adjudicate a game as drawn in a clearly drawn ...
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  • 161
11 votes
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What is the order of actions in chess under FIDE rules?

The FIDE Laws of Chess provide some guidance. Rule 6.2.1 says you must move the piece before hitting the clock: During the game each player, having made his move on the chessboard, shall stop his ...
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  • 15.2k
10 votes
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50-move rule: FIDE wording seems weird

Hi thanks for the question! Yes this is what FIDE are saying. If you are about to play the 50.0th move of the sequence, or to cause a position to occur for the third time, then you need to claim ...
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  • 9,408
10 votes

If both sides move at random, but legally, then how many games will be a win for White or Black, if not a draw?

The number of games is huge but finite, and estimates have been made based on a number of assumptions. But that question has been asked before already, so I won't go into the details here. A short ...
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  • 10.2k
9 votes

What are the hardest pawnless endgames that go over the 50-move rule?

If you mean "hardest" == "longest": There are 7-man table bases available and it is said that the longest pawnless ending takes 549 moves. It is KQB vs. KRBN. Resources: http://tb7.chessok.com/...
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  • 191
8 votes

Simltaneous checkmate and draw claim on the 50th move

The Laws of Chess say: 9.3 The game is drawn, upon a correct claim by the player having the move, if a) he writes his move on his scoresheet and declares to the arbiter his ...
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  • 364
8 votes

Proof of irreversibility of 50 move rule

The two irreversible moves can be proved irreversible (it is impossible to replicate that board state later in the game) like so: Assumptions: - Pawns can't move backward. - Every pawn move moves ...
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7 votes
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Is a forced draw by 50 moves possible with Bishop and Knight endgame?

It takes at most 33 moves to win this endgame from any position (excluding positions where bishop or knight can be captured). See https://en.wikipedia.org/wiki/Bishop_and_knight_checkmate and ...
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  • 20.4k
7 votes

If both sides move at random, but legally, then how many games will be a win for White or Black, if not a draw?

It would seem that the longest games would end up being the most numerous, by far. On any particular move, if you end a game, that's one game, but if you let it continue, it's many games. It would ...
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  • 15.2k
7 votes
Accepted

50-move rule: only the last 50 or any consecutive 50?

She can claim a draw. Article 9.3 of the FIDE Laws of Chess, 2018, emphasis mine: 9.3 The game is drawn, upon a correct claim by a player having the move, if: 9.3.1 he writes his move, which cannot ...
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6 votes

The 50 Move Rule

Fide Laws of Chess 5.2 e. The game may be drawn if each player has made at least the last 50 moves without the movement of any pawn and without any capture (see Article 9.3). 9.3 The game is drawn, ...
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  • 3,425
6 votes

How long can a player hold off a draw by the 50-move rule?

The answer is trivially the starting position - [fen ""] This exact question hasn't been asked before (I think) but it has been answered here. Here is the relevant part of that answer - ...
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  • 75.7k
6 votes

What is the need for repetition rules given the 50 & 75 move rules?

are the (optional) threefold-repetition rule and the (mandatory) fivefold-repetition strictly necessary? Yes, they are necessary. Something which players sometimes forget is that arbiters are people ...
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  • 75.7k
5 votes
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What is the source of the house-rule 18-moves?

I grew up in Spain and we used a 20 "move rule" instead of 18. We played exactly as you said, if a player is left with a single king, the other has to mate in 20 moves or less to win the game. ...
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5 votes
Accepted

Simltaneous checkmate and draw claim on the 50th move

I would let the checkmate stand but the true answer is that it does not matter. The player has the right to offer a draw at any time and the claim according to article 9.3 is also a draw offer. You ...
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5 votes

Chess endgame database+50-move rule=potential error?

You are right that tablebases do not automatically contain information pertaining the fifty move rule. To use tablebases accurately currently engines use the DTZ50 metric (distance to zeroing with ...
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5 votes

Why doesn't castling reset the 50 moves rule?

I don't know the reason, but I can make a guess. In standard algebraic notation, it's fairly easy to look at a scoresheet and see whether a capture has been made or a pawn moved. Captures have an "x"...
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  • 15.2k
5 votes
Accepted

Can a KB vs. KB endgame be declared drawn if a checkmate can occur and the 50-moves-rule doesn't apply in a Blitz game?

What is the requirement for an arbiter in the below position if one party is seriously on time trouble say 2mins against 15seconds in a blitz tournament If this party claims a draw? If the arbiter ...
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  • 75.7k
4 votes

Why doesn't castling reset the 50 moves rule?

After some discussions in the comment section I think it's time for me to start answering this question to the best of my understanding. First off, let's discuss the use of the concept "the state of ...
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  • 7,332
4 votes

Why doesn't castling reset the 50 moves rule?

Capturing and move pawns are not reversible, in the sense that the position occurring before the capture or the pawn move cannot any longer occur in that game. To make an example, after 1 e4 d5 2 e:...
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  • 1,166
4 votes

Is it OK to look at the list of played moves during the game to determine the status of the 50 move rule?

Yes you're absolutely allowed to look at the score-sheet. What you're not allowed to do is make special symbols/notes on the scoresheet to remind you of things. But that's non-applicable here.
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4 votes

Does anyone have a version of the 50x50 article by Nikita Plaksin?

Hi Arnaud thanks for your question. The problems themselves can all be found in pdb.dieschwalbe.de. Type K='50' AND A='Plaksin' AND S='Problem' AND YEAR='1979'. All 50 are there numbered, with ...
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  • 9,408
4 votes
Accepted

What is the longest tablebase win that includes draw rules?

Unfortunately looking for the longest mates on Kyrill Kryukov and checking with Syzygy won't give you the answer. The mate lengths ignoring the 50 move rule don't correspond with the mate lengths when ...
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