
The Hardest chess problem in the world? - ColinWright
http://hebdenbridgechessclub.blogspot.com/2011/02/hardest-chess-problem-in-world.html
======
dsjoerg
"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.

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

~~~
dsjoerg
"strictly" changes the meaning of the sentence. it suggests that there are
"strict" and "not so strict" interpretations of the chess rules, and that if
you're not so strict, the move is OK.

but promoting to the other color is not allowed, even under "not so strict"
interpretations of the rules of chess.

an example of things that may be permitted in "not so strict" chess: taking
back your move, not moving a piece even though you touched it, talking to the
other player, agreeing to play on even though you've had a threefold
repetition.

~~~
javert
I mean really, the rules are the rules, and there is no ambiguity. So a
"strict reading of the rules" is the same thing as a "reading of the rules."
Because, as you say, there is no such thing as a reading of the rules that
violates the rules and is thus merely "less strict."

For example, under the rules, not moving a piece you touched and promoting to
the other color are the same: illegal.

The examples you are giving are simply cases where the other player is likely
to _let_ you break the rules if it's a very casual game.

So again, having "strictly" in the sentence is, technically, purely redundant.

It's a dumb thing to say, but then again, it probably made the piece more
suspenseful and thus more fun to read.

~~~
v0x
You seem to imply that all rules are equally as important as one another,
while I would say they are not. For example, in a casual game of chess, most
would be okay with some of the aforementioned deviations, like taking back a
move. I do not think most would accept it if you started moving your pawns
around like queens.

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legohead
For an actual legal and cool puzzle:
[https://www.youtube.com/watch?v=iSKtG-8TwI0](https://www.youtube.com/watch?v=iSKtG-8TwI0)

~~~
Max_Horstmann
Also cool: white to move and NOT mate

[http://www.chess.com/blog/AaronGo/white-to-move-and-not-
mate](http://www.chess.com/blog/AaronGo/white-to-move-and-not-mate)

~~~
jerf
Would someone like to post a ROT13 of the solution to that, if they have it?

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rectang
Ebbx gb P fvk

Zbir gur Ebbx gb n fcbg jurer vg eryrnfrf gur cva ba gur bccbaragf Ebbx, juvpu
pna gura pncgher gur ovfubc juvpu unf perngrq gur qvfpbirerq purpx.

~~~
jerf
Thank you.

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danso
I enjoyed the solution...I played chess when I was young but obviously not at
an elite level, as I did not know of this rule. But what amused me was --
legal or not -- that I just had never even thought of doing that kind of move,
_ever_. Technicalities aside, it's a nice thinking-outside-of-the-box example.

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aaronrenoir
If chess is a analogy of war and a pawn infiltrates the other side. I believe
he has the right to choose a side. I mean he may scale the castle wall only to
die releasing a captured prisoner, or he may disrobe a night and get back on
the battle field. I love this idea.

~~~
pnut
I thought defectors were also executed by opposing armies?

Who would want a known traitor in their ranks?

~~~
dorgo
I would want. Just find a way to use him for your purposes..

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ikeboy
Poking around that site's replacement, I bumped into
[http://www.hebdenbridgechessclub.co.uk/2011/02/11/castling-v...](http://www.hebdenbridgechessclub.co.uk/2011/02/11/castling-
very-long/). Also interesting, and involving no-longer-valid rules.

~~~
chengiz
The Anon v Macieja is sweet.

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praptak
I remember reading about a chess puzzle where a similar "out of the box"
thinking was required which would probably put it outside of reach of computer
solvers. As a plus it was within currently legal rules.

The winning move was en passant and the solution required observing that the
only way the situation could have arisen was the opposite pawn moving 2 ranks
forward, making this move possible.

~~~
stouset
This doesn't seems like the kind of move that would be the crux of a puzzle,
tripping up both computer and human. En passant captures are a normal,
straightforward move in chess that few above amateur level would overlook. En
passant captures are the _first_ move you tend to look at if an opponent has
moved their pawn two spaces adjacent to one of your own.

~~~
fenomas
> En passant captures are the first move you tend to look at if an opponent
> has moved their pawn two spaces..

GP is clearly saying that you're not given the information that a pawn has
moved two spaces, the trick of the puzzle is to infer from the board's layout
that such must be the case.

Seems damned clever to me. From a quick google it appears that such things are
known as "retrograde puzzles".

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joseraul
Also very challenging for chess players is retrograde analysis, where you have
to find the only possible legal moves to reach the given position.

See the cover of this book by Smullyan [http://ecx.images-
amazon.com/images/I/81y-bMMYCoL.jpg](http://ecx.images-
amazon.com/images/I/81y-bMMYCoL.jpg)

~~~
sanderjd
Thanks for that link, it was fun and took me quite awhile to figure out!

~~~
philh
Vs gur obneq vf hcfvqr-qbja, juvgr cebzbgrq gb n ovfubc naq gura oynpx zbirq
bhg bs purpx. Bgurejvfr V pna'g guvax bs nalguvat. Vf gung jung lbh pnzr hc
jvgu?

~~~
Relaxx
V guvax juvgr unq n xavtug ba o6, zbirq vg gb n8 naq gura gur oynpx xvat
pncgherq vg.

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atmosx
> "I first encountered this position in June 1937 [...]"

OT remark: Jesus. I work with the elderly, mostly. I would love to have her
clarity of thought if and when I reach her age. I've heard before that playing
chess retains hair loss and mental deterioration, especially in the elderly.

~~~
hissworks
I, too, was curious about Lady Cynthia Blunderboro. It seems she's a fictional
persona prone to hoaxes.

[https://www.google.com/search?q=lady+cynthia+blunderboro](https://www.google.com/search?q=lady+cynthia+blunderboro)

~~~
Grue3
The fact that she by chance happened to have the very same position during
normal play gave it away. The probability would be astronomically low.

~~~
swang
Not sure if you're referring to something else. But in the story she is just
replaying the game that her grandfather played back in the 1800s. She didn't
actually come up with that move from playing.

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sandworm101
If we are playing fast with the rules re sides, was there any rule at the time
saying the black King couldn't take the black Knight?

That would break the check, force white to move the rook to block, allow the
black king to take the rook, and place black in a winning position.

~~~
arasmussen
> "force white to move the rook to block"

A better move would be to just move your king out of check and to go protect
your rook.

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imaginenore
From FIDE rules:

> _When a player, having the move, plays a pawn to the rank furthest from its
> starting position, he must exchange that pawn as part of the same move for a
> new queen, rook, bishop or knight of the same colour on the intended square
> of arrival._

> _promotion: 3.7e. Where a pawn reaches the eighth rank and is replaced by a
> new queen, rook, bishop or knight of the same colour._

[https://www.fide.com/fide/handbook.html?id=171&view=article](https://www.fide.com/fide/handbook.html?id=171&view=article)

~~~
ColinWright
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!

~~~
bradleyjg
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 third queen or a fifth rook rather than a second
or third.

~~~
wowaname
That doesn't really imply much. Having a fifth rook does not correlate at all
to having a piece of the same or opposite colour. Regardless, based off that
rule, a piece of the opposing colour would be defined by "any other peice
[sic] which he may deem more useful for his attack" in that play, so it sounds
perfectly legal to me.

~~~
mikeash
If you arrange your game just right, you can legally have up to ten rooks (or
bishops or knights, or nine queens) of the same color on the board at once.
(This will probably not be possible without the cooperation of the other
player.)

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toolslive
reminds me of "0-0-0-0". Before the rule was added that castling was a 'row
move', you could promote an e-pawn to a rook and than castle superlong by
moving the king from e1 to e3 (and the rook to e2). This oversight in the
rules was later corrected.

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DavidWanjiru
I'm not much of chess person, but I don't get it. Even if the black knight
plays for white, it's still not checkmate. What prevents the black king from
"eating" that black knight?

~~~
zornthewise
The black knight plays for black.

~~~
DavidWanjiru
In the solution presented at the end of the article, whose turn to move is it?
Who can't make any further moves coz they've been check-mated? That's what I
don't get. If it's white, white can still move their king back towards their
home row and there's more than one move left in the game. If it's black, black
can move the black knight in between the two kings and we'd still have more
than one move left.

~~~
teahat
Black is in check from the white rook. Moving the black night doesn't escape
the check, so isn't a legal move.

~~~
DavidWanjiru
Now I get it. The "beef" is that white replaced their white pawn with their
opponents black knight, which of course the black king can't eat...

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philh
The problem isn't showing up for me, but cached version:

[http://web.archive.org/web/20150918165831/http://3.bp.blogsp...](http://web.archive.org/web/20150918165831/http://3.bp.blogspot.com/-RwlnMx0bj50/TVTqt0g8EMI/AAAAAAAAASs/0GQKsEhy3yY/s1600/Mate+in+1+problem.jpg)

White to play and mate in one.

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electrotype
Why is it illegal now? I think it would be more fun if is was legal for the
very, very, few cases where it can actually help a player.

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t0mbstone
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

~~~
twcooper
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.

~~~
fizixer
Yeah I would be disappointed too if, for example, I'm asked to find out how to
avoid a clear checkmate and I spend a lot of time thinking and fail, and then
I'm told "you flip the board over and run away".

~~~
twcooper
It doesn't take long to go through all of the permutations in your head and
figure out that it's something really odd, but this line in the second
paragraph should have let every reader know that the solution was gimmicky:
"If I told you that the solution is a VERY unusual move that is no longer
strictly within the bounds of the rules of the game then that might help you a
little bit." From then on, I read the story instead of trying to solve the
problem.

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delinka
SPOILER ALERT

I don't know about "hardest" but I do tend to wonder: who'd have thought to
promote to anything other than one's own color? Kinda feels similar to doing
some odd operation "in a single processor instruction" but the trick is that
the ISA in question went the way of the dodo about four decades ago.

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dnautics
I moved the pawn down one space, assuming the board was backwards and the
white pawn was on the second rank.

~~~
philh
That's not mate, the black king can move diagonally to G1. Same thing black
would do if white promoted to a white piece.

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parennoob
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](https://en.wikipedia.org/wiki/Saavedra_position)

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nichochar
The article is interesting, but the title is frustrating because clickbaiting.
I personally love chess and love challenges, and this was downright
disappointing. I don't encourage clickbaiting. This is a shame because the
article is interesting

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jkot
Harder problem is to find a sequence of turns, where white always wins, from
starting position.

Anyway this turn is not legal in chess I learned.

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cyphar
Definitely an interesting hack, it's interesting that the rules were updated
to make it illegal.

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binarymax
For a really good problem, with legal moves, feast on this:

[http://gameknot.com/analyze-
board.pl?bd=0&fen=8/3P3k/n2K3p/2...](http://gameknot.com/analyze-
board.pl?bd=0&fen=8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4%20w%20--&rnd=0.5244399076637669)

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grondilu
That's the best example of out-of-the-box thinking I've ever seen in chess.

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raam86
Can't the knight capture the white king resulting in checkmate for black?

~~~
IkmoIkmo
No, it'd have to be in the position of the white pawn in the initial position
to reach the king. It moves two pieces (not three) horizontally and 1 piece
vertically, or vice versa.

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z3ugma
Could it also have been a black rook as well?

~~~
halosghost
No. A Black rook would have allowed black to b8b7 and block the white rook
from the final checkmate. A knight, on the other hand, would not be able to
block the white rook and would therefore result in a checkmate.

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kostyk
not really valid as white becomes black.

~~~
ColinWright
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!

~~~
Maken
So, promoting a pawn in chess is undefined behavior?

~~~
dragonwriter
No, its defined (both then and now), its just the spec has had breaking
changes from earlier versions.

