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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 movement of any pawn and without any capture. 75-move rule: 9.6 If one or both of the following occur(s) then the game is drawn: (...) any series of at ...


20

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 claim was based on an intended move, this move must be made in accordance with Articles 3 and 4


18

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 in 1956 : [fen "5KBN/p2ppp1r/1p4pp/b7/RP6/1PP4P/1RpPPPkP/n1B1Q1N1 w - - 0 1"] 1. Nf3 Rg7! 2. Kxg7! (2. Qg1+?? draws) There is an apparent mate in three moves:...


15

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 his scoresheet and declares to the arbiter his intention to make this move which will result in the last 50 moves by each player having been made without the ...


15

Your opponent has 50 moves, but every time a pawn is moved the count is reset. So, he could have hundreds of moves if he has a few pawns on the board. If he has no pawns, then 50. The count is also reset if any piece or pawn is captured.


14

Yes, many times. Ivanchuk- Kamsky 2009 is one example, but there are hundreds if not thousands of others. Ushenina - Girya 2013 made some news recently because Ushenina couldn't mate with knight and bishop in time.


13

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 because you are always allowed to check your scoresheet. You would be very foolish to not check your scoresheet first because there are penalties for an incorrect ...


11

From the FIDE rules (emphasis added): 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 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 b. the ...


11

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 own clock and start his opponent’s clock (that is to say, he shall press his clock). This “completes” the move. According to rule 8.1.2, you must move the ...


10

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 before you move. I think this is because after you have moved the piece, your opponent is allowed to respond, without waiting for you to punch the clock. If you ...


10

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 convert a knight-and-bishop checkmate within the required 50 moves, and the game was drawn. So this is a case where it's a theoretical win, but the stronger side ...


10

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 position when both players were electing to play on, hoping that their opponent would falter. Usually in cases where a draw was as good as a lost for both ...


9

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/articles/Top8DTM_eng And in case you are too lazy to go through the moves by yourself :-): http://tb7.chessok.com/probe/745/61 I think that is what is known today. ...


8

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 it forward. - Pieces can't be added to the board. - There is no way to create a pawn (unlike queens, bishops, knights, and rooks which can be created via pawn ...


8

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 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 ...


8

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 answer given on Wikipedia is at least 10123, based on an average branching factor (moves per position) of 35 and an average game length of 80; after only 10 plies (...


7

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 references there. So, no, a forced draw is not possible in this endgame. However if the defending side is playing perfectly (e.g. an engine with tablebase), it could ...


7

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 seem, therefore, that the greatest number of games would continue until one side had a single piece left. The remaining piece should not be a knight or bishop, as ...


7

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 be changed, on his scoresheet and declares to the arbiter his intention to make this move which will result in thelast 50 moves by eachplayer having been made ...


6

An interesting detail of the 50 move rule: As only the player to move may claim a draw (either by declaring that the 50 move limit has been reached or by declaring his intention to make a move after which the limit will be reached), if the 100th half-move that is not a capture nor a pawn move is a checkmate, then the game is not drawn. See e.g. Arbiter's ...


6

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, upon a correct claim by a player having the move, if: [...] b. the last 50 moves by each player have been completed without the movement of any pawn and without ...


6

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 - The maximum number of moves in a chess game is not infinite, it's 11797 plies = 5898 moves and a half. This is due to the fifty-move rule. As an interim ...


5

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 are concerned with a peculiar situation where player A wants a draw and does not want to win, for whatever reason, while player B does not want to draw (even at ...


5

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. However, this "rule" only applied in friendly matches and was never enforced in tournaments. Our coach made us play like this for several reasons: It promotes ...


5

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 fifty move rule) which tells you the number of winning moves until the 50-move count is reset. If this number is too big, the position is evaluated as a draw. ...


5

Do you mean "what is the minimum necessary number of moves?", or "what is the maximum allowable?" Tony has already answered the second question - it could legally be thousands of moves depending on the position. As long as the same position is not reached more than twice and there is no 50 move stretch without a pawn move or capture, the game can go on ...


5

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" in them, and pawn moves don't have a piece listed. But if loss of castling rights also triggered the 50 move rule, you'd have to look at the rest of the game (...


5

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 happens to notice this position, can they call it as draw before the 50 moves rule is reached? No. Helpmate is still possible hence the arbiter cannot intervene. ...


4

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 the game". Although I sort of understand what you're trying to say I still wonder about weird cases such as the following: e4, e6 2. e5, d5 3. Nf3 Has the "...


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