6 ms·
They dont really spell it out but they mean "from this position the player has 218 possible legal moves to choose from"
by codeulike 1y ago
They dont really spell it out but they mean "from this position the player has 218 possible legal moves to choose from"
- WithinReason 1y agoThanks, I misunderstood the entire article. Great writing!
- sverhagen 1y agoHow can those two things be true at the same time? Unless you appreciate misunderstanding what you read...?
- burnished 1y agoWhat other reason would a person have for juxtaposing two statements?
- Sharlin 1y agoHow could someone ever write something while intending to convey the exact opposite meaning?
- absoflutely 1y agoYou hit the nail on the head. They aren't both true which is why the second sentence is sarcasm.
- wodenokoto 1y agoI thought it was "How many moves in a game does it take to reach this position"
- coolness 1y agoI also thought this but OP is right: https://dev.timenote.info/de/Nenad-Petrovic https://dev.timenote.info/de/Nenad-Petrovic > In 1964 Petrović constructed a position with 218 possible moves for White.
- jmkd 1y agoSame, which also damages my personal policy of reading the link before any HN comments.
- stephenhumphrey 1y agoHuh. I also have that personal policy. Yet this time I jumped first to the comments before reading the article. I’m not certain why. Perhaps I subconsciously intuited that the ambiguity in the headline might be resolved by some of you smart people. Brains are weird; mine is, anyway.
- jl6 1y agoThe right™ order is to check the comments before the article, but to read the article before commenting.
- winternewt 1y agoI thought it was "there's no position in chess that requires more than 218 moves to reach."
- unkulunkulu 1y agoI thought “there is no chess problem that is both reachable from starting position and requires more than 218 moves to solve”
- binarymax 1y agoThere are no more than 218 ways to interpret this title
- fer 1y agoIt'll take at most 218 comments on HN to figure out the meaning of the submission title
- matheusmoreira 1y agoIt'll take at most 218 characters to express the fact I did not understand the submitted article's title.
- leoff 1y agoI seriously thought they meant "it's not possible to have a chess game with more than 218 moves"
- ojo-rojo 1y agoYeah, I'm still confused.
- fwip 1y agoThere is no reachable[1] chess position[2] at which a player has more than 218 valid moves[3] to choose from. [1] Able to happen while following the rules of chess [2] The arrangement of chess pieces on the board [3] A valid move is the motion of one piece to a place on the board, which doesn't break the rules of chess - e.g: "King to E4."
- brumar 1y agoSame. I was astonished it was remotely possible to do this.
- weinzierl 1y agoBut this an interesting problem too. More specifically is there an upper bound for the number of moves in a legal chess game?
- kevindamm 1y agoNot explicitly, but when you consider the "cannot repeat the same board layout three times" rule, the number of moves possible in a game does have a limit.
- jibal 1y agoThe 3 repetition draw rule has no bearing on the number of possible chess positions. And for the number of possible moves in a game the 50 moves with no capture or pawn move rule is a much more stringent limit. BTW, the 3 repetition rule only comes into play is one of the players invokes it ... games can legally have more than 3 repetitions, but not more than 5 repetitions.
- kevindamm 1y agoI didn't know it required a player to invoke it, I was basing the statement on chess implementations I've read (and written) where it kicks in automatically... but the 5-time limit you mention still supports my case that there's an upper limit. As long as the number of pieces remains the same, there are a finite number of arrangements for them so eventually (after a finite number of moves) a position would be repeated enough times. If a piece is captured (or converted) it resets this but still yields a finite number of new arrangements. Eventually you either cannot avoid the repetition, or a win condition is met, or a draw for insufficient material. Compare this to, say, the L game, where the number of moves is unbounded.
- jibal 1y agoYour "case" that there's a limit isn't in question ... as I said, the 50 move rule is a far more stringent limitation. And those 50 moves cannot include repetitions--they are captures and pawn moves, which are irreversible. If you read my comment that you responded to carefully, you will find that it is precise and accurate--as I said, the repetition rule has no bearing on the number of positions. This horse is dead, so I'm moving on.
- arc-in-space 1y agoAh, thank you. I was confused reading this article, thinking it's about the unique position that takes the most moves to reach.
- BrenBarn 1y agoYes, very strange that the phrase "possible moves" never occurs in the article. The key word is "possible". The article consistently just uses the phrasing "have moves" but this is not an obvious way of phrasing things to the average person (although I think it's more common in chess lingo).
- unkulunkulu 1y agoin chess lingo the most common is “legal moves”
- fsckboy 1y agoin chess lingo, most common is "moves"; only in a weird circumstance (beginners?) would you need to say "legal". the "possible" qualifier would probably be used for an "english" reason rather than a "chess" reason, to suggest "future" moves as opposed to the moves already made to get to a position. it would be more likely for whatever reason to say "how many possible moves" than "how many future/hypothetical moves", i.e. the use of possible is not to rule out the idea of impossible, simply to mean how many "could you make now from a particular position" and/or i guess to suggest "possible initial moves" as opposed to future follow-on moves. the ambiguity is not really in chess, it's in english (and probably every other language also)
- BrenBarn 1y ago> the ambiguity is not really in chess, it's in english (and probably every other language also) Sure, but the article is written in English. :-)
- fsckboy 1y ago"moves" includes the idea of possible. "reachable" chess positions can only be the result of moves which are only those possible, and any follow-on moves would also only be those that are possible
- BrenBarn 1y ago
- davedx 1y agoBut black has no king, so surely the game is over and there are no more legal moves? Why does black have two pawns but no king? I don’t understand any of this
- electroly 1y agoEvery board on the page, with the exception of the illegal "all queens" board, has a black king. The king is the one with the cross above the crown. In the first board, the 218 winner, it's at A1.
- davedx 1y agoThe first image, which I assume is the solution because the title is 'Reachable chess position with 218 moves for White, published by Petrović in 1964.', has no black king?
- electroly 1y agoLook again. It's at A1. You may be confusing that symbol with a different piece.
- davedx 1y agoUgh. Sigh, I see it now - I thought that was the white king, because it has quite some white in it. I will allocate 50% blame to my brain and eyes, and 50% to whoever designed a black king to have so much white in it :P Thanks!
- jibal 1y agoNo, it's 100% on you. If the piece on a1 is a white king, then what's the piece on f1? And why would there be no black king, when the subject is reachable (and thus legal) positions?
- nabla9 1y agoIt should be obvious that there are no 8.7 × 10^45 possible chess moves from any chess position. All pieces have less than 32 moves per piece and 19 pieces means less than 608 moves.
- electroly 1y agoNo, they do mean possible moves and they don't mean maximum length game. There are on the order of 10^45 reachable chess positions. The article did not say that was the number of moves from one position. The article says 218 is the maximum number of moves from one reachable position--it's the whole point of the article!
- amitparikh 1y agoRight, and by "reachable" they mean it is theoretically possible to get to this board position through a normal (albeit obviously methodically chosen) series of moves.
- amelius 1y agoIf only they had appended "to choose from" to the article headline, it would have been clear from the start.
- jibal 1y agoThe caption on the first position is "Reachable chess position with 218 moves for White, published by Petrović in 1964." And the title is unambiguous: "There is no reachable chess position with more than 218 moves" -- that cannot possibly mean "There is no reachable chess position that it takes more than 218 moves to reach". Also, lichess is a chess site, where people are certain to know that chess games can go way beyond 218 moves.
- Agingcoder 1y agoYeah I gave up when I realized I didn’t understand what problem he was trying to solve
- stavros 1y agoAh, wow, I read the article wrong all this time, thank you. I thought they meant "the maximum number of moves you can make to reach any chess position is 218", and I was wondering why the article made no sense to me.
- kelipso 1y agoIs that weird? I feel like it’s plausible though. Very rare to have chess games with more than 200 moves.
- stavros 1y agoYeah I kind of thought that it meant "you can get to any valid position in 218 moves max", it was hard to parse.
- OwlGoesHoot 1y agoI read it as “there is no legal position for which the minimum number of moves necessary to reach it is greater than 218” but I also did not read the whole article before coming to check the comments
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- refulgentis 1y agoIt’s also rare to have one with more than 50 moves. I’m curious if this class of observation will help establish a true bounds. Especially because we don’t have a definition of what it means - my instinct is to first do that, so “infinity” isn’t the obvious upper bound.
- KingLancelot 1y ago[dead]
- aqme28 1y agoI thought they meant that no game could go more than 218 moves. I can imagine some upper limit since three-fold repetition ends the game. But it’s a lot higher than 218.
- hibikir 1y agoAnother relevant rule is a draw after 50 moves without a capture or a pawn move. But yes, the maximum number of moves would be extremely large when both players are trying. Just think of a first 2 moved allowing the king out, an outrageous king march, followed by another pawn move...
- amenghra 1y agoThe confusion is perhaps caused by the word “reachable”. “No legal chess position with more than 218 possible moves” would have been more clear imho.
- hx8 1y agoI had the same confusion, until they showed the existing 218 position and realized it was about maximizing white's legal moves.
- NooneAtAll3 1y agothe word "possible" is missing
- chankstein38 1y agoThank you. I don't understand why people can't just explain what they're talking about before spending paragraphs talking about it. I thought this was like "After 218 moves there is no reachable chess position" which made no logical sense to me but I don't know enough about chess.
- layman51 1y agoOh, that makes more sense. That is an interesting thing to examine, but I wonder how useful it is. It reminds me of a tip I heard about improving at chess by actually counting all legal moves in a position so that you ensure you're not completely overlooking an option.