The Hardest chess problem in the world? • Hacker News Board

Re: The Hardest chess problem in the world?

#41

Post by jMyles » Fri, Sep 18, 2015, 6:22 PM UTC

javert wrote: post #20

dsjoerg wrote: post #15

"no longer strictly within the bounds of the rules of the game" I take exception to _strictly_... it's just flat out illegal now, no "strictly" about it. I would have been less ticked off if the article had simply written "no longer within the bounds of the rules of the game." It is fascinating that the move was formerly legal though.

Yeah, but putting "strictly" there does not change the meaning of the sentence, it's just a superfluous word.

It gives the sentence a nuance that suggests ambiguity, as if prohibition of this move requires some particularly "strict" reading of the rules. I agree that makes the sentence weaker, and given the gravity of the sentence, makes the article seem somewhat amateur.

Re: The Hardest chess problem in the world?

#42

Post by aidenn0 » Fri, Sep 18, 2015, 6:27 PM UTC

bradleyjg wrote: post #18

ColinWright wrote: post #12

Earlier quoted context omitted.

Thank you for the reference - appreciate that. I wonder when that explicit rule was introduced. It says in the article: "But in fact, at the time this game was played there was no specific rule stating that a pawn had to be promoted to a piece of the same colour!

Sarratt in his Treatise on the Game of Chess (1808) says: "When a player has pushed a Pawn to Queen, he is at liberty to make a second Queen, a third Rook, or any other piece which he may deem more useful for his attack or defense". While this doesn't explicitly say that he must promote to a piece of the same color, it implies it. After all if the piece could be promoted to either color it would make sense to say a t…

Not at all, it would be a third Rook of the alternate color.

Re: The Hardest chess problem in the world?

#43

Post by ubernostrum » Fri, Sep 18, 2015, 6:28 PM UTC

ColinWright wrote: post #5

kostyk wrote: post #2

not really valid as white becomes black.

Did you actually read right to the end? "But in fact, at the time this game was played there was no specific rule stating that a pawn had to be promoted to a piece of the same colour!

Of course there was also no rule saying that chess functioned on a restrictive rules system and a lot of evidence that it instead functioned on a permissive system. Which would invalidate the "no rule says I can't" argument.

(when designing a game's rules, "restrictive" means the approach is "everything is permitted by default, unless explicitly restricted", while "permissive" means "everything is forbidden by default unless explicitly permitted" -- if we assume that chess is a restrictive-rules game, we can similarly mate in one from almost any position by simply inventing new pieces with unusual abilities and declaring that "the rules don't say you can't!")

Re: The Hardest chess problem in the world?

#44

Post by ColinWright » Fri, Sep 18, 2015, 6:30 PM UTC

[deleted] wrote: post #39

monochromatic wrote: post #19

Earlier quoted context omitted.

I'm a total newbie at chess... but what's the problem with promoting to a queen?

[deleted]

You might be responding to a different puzzle (the original) from the one now being discussed (from https://news.ycombinator.com/item?id=10240289 )

Re: The Hardest chess problem in the world?

#45

Post by mikeash » Fri, Sep 18, 2015, 6:34 PM UTC

t0mbstone wrote: post #32

A poorly phrased question that lacks context != cleverness The "puzzle" relies on an obscure situation which isn't even a rule. You might as well claim that the kings can checkmate each other, or that the rook can spontaneously transform into a queen. HEY GUYS CHECK OUT THIS FAKE PUZZLE THAT REQUIRES YOU TO IGNORE EVERYTHING YOU KNOW ABOUT CHESS RULES FOR IT TO WORK

It's not a rule now. This move was legal at the time.

You can reasonably object that you shouldn't be expected to know that history, but that makes it quite different from "rook can spontaneously transform into a queen" and similar.

Re: The Hardest chess problem in the world?

#46

Post by mikeash » Fri, Sep 18, 2015, 6:36 PM UTC

ubernostrum wrote: post #43

ColinWright wrote: post #5

Earlier quoted context omitted.

Did you actually read right to the end? "But in fact, at the time this game was played there was no specific rule stating that a pawn had to be promoted to a piece of the same colour!

Of course there was also no rule saying that chess functioned on a restrictive rules system and a lot of evidence that it instead functioned on a permissive system. Which would invalidate the "no rule says I can't" argument. (when designing a game's rules, "restrictive" means the approach is "everything is permitted by default, unless explicitly restricted", while "permissive" means "everything is forbidden by defaul…

If the rule was simply, "A promoted pawn may be exchanged for any piece," then that would fit within a permissive system, and still qualify as "nothing says you have to promote to the same color."

Re: The Hardest chess problem in the world?

#47

Post by dalke » Fri, Sep 18, 2015, 6:49 PM UTC

doomrobo wrote: post #31

Max_Horstmann wrote: post #17

Earlier quoted context omitted.

Also cool: white to move and NOT mate http://www.chess.com/blog/AaronGo/white-to-move-and-not-mate

Is a castle legal in this case?

No. Castling can only occur if the king has not moved. By convention, white's pieces start at the bottom of the depicted board - the first row. In this puzzle, the king is in the last row, which means it has moved at least 7 steps.

Re: The Hardest chess problem in the world?

#48

Post by parennoob » Fri, Sep 18, 2015, 6:50 PM UTC

This is interesting, but as the author acknowledges, not legal in modern games.

Another famous position which relies on (legal) underpromotion: https://en.wikipedia.org/wiki/Saavedra_position

Re: The Hardest chess problem in the world?

#49

Post by Maken » Fri, Sep 18, 2015, 6:56 PM UTC

ColinWright wrote: post #5

kostyk wrote: post #2

not really valid as white becomes black.

Did you actually read right to the end? "But in fact, at the time this game was played there was no specific rule stating that a pawn had to be promoted to a piece of the same colour!

So, promoting a pawn in chess is undefined behavior?

Re: The Hardest chess problem in the world?

#50

Post by twcooper » Fri, Sep 18, 2015, 6:57 PM UTC

t0mbstone wrote: post #32

A poorly phrased question that lacks context != cleverness The "puzzle" relies on an obscure situation which isn't even a rule. You might as well claim that the kings can checkmate each other, or that the rook can spontaneously transform into a queen. HEY GUYS CHECK OUT THIS FAKE PUZZLE THAT REQUIRES YOU TO IGNORE EVERYTHING YOU KNOW ABOUT CHESS RULES FOR IT TO WORK

I think you're just disappointed because you wanted to solve a chess problem. I liked the article because I read it as a story to be enjoyed rather than a problem to be solved.