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

Logically, if 75 moves have been played, 50 moves would've also been played. This sounds ridiculous. It is like saying "I would buy this book if it cost under $60 and it costs under$40". So, what is the logic behind that?

• In cases where the 75-moves rule applies (e.g. 2B vs N, IIRC), it replaces the 50-moves rule : you cannot claim a draw after 50 moves, but you can do so after 75 moves. Oct 31, 2018 at 13:44
• So do you mean that the 50-move rule does not apply to 2B vs N games? Oct 31, 2018 at 14:10
• @Evargalo that used to be the case (in various forms) from 1928 to 1992: en.wikipedia.org/wiki/Fifty-move_rule#History Oct 31, 2018 at 15:22
• Yes, I was confused between two different 75-moves rules. Annatar's answer is spot on. Oct 31, 2018 at 16:23

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 least 75 moves have been made by each player without the movement of any pawn and without any capture.

(emphasis mine)

As you can see, the decisive difference is that the 50-move rule only applies if a player correctly claims it, while the 75-move rule applies independently of any claims. So, in the 50 to 75 move window, the players can claim for a draw, but don't have to (and play on). Only when the 75th move without pawn moves or captures has been reached, the arbiter may interfere and declare the game drawn.

• The better question is, given that at 50 moves it is objectively correct for one of the players to claim a draw, so why not just make it forced then? Oct 31, 2018 at 18:55
• @eyeballfrog: perhaps because both players still believe they can win when their opponent makes a blunder, or runs out of time. If both players believe they can win then why would either declare a draw when they did not have to? Oct 31, 2018 at 19:49
• @eyeballfrog The 50 move rule requires a player to notice it. That's not a given. Nov 1, 2018 at 11:11
• @EricLippert The same argument applies to the 75-move rule, which does cut the game off. This is poor rules design--either forcibly end the game or don't. Nov 1, 2018 at 14:45
• @eyeballfrog It is not always "objectively correct for one of the players to claim a draw". For instance, say Black and White are playing in a tournament; it's the last game for both of them, currently each has n points, and the tournament leader has n+1 points with no more games to play. The only way either Black or White can catch the leader is by achieving an outright win for a full point. In this case, claiming a draw is a lose-lose situation. Not all games are zero-sum. Nov 1, 2018 at 20:38

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 players, i.e. a win would secure prize money, a draw would win no prize money. Arbiters have a life too. ;>)

• I have a life? Srsly? You're the first to tell me that. That's so nice, have an upvote :-) Feb 19, 2021 at 19:17