circularsquare
Branch Unspecified
10 Feb 2012

# Chess Puzzle.

Hello to all chess lovers.
In the following puzzle you don't have to think ahead you have to think back.

It is chance of black to move. What move has white just played ?

At first sight it seems it is impossible to solve since white king is surrounded by a double check everywhere.

simplycoder

Branch Unspecified
23 Feb 2012
circularsquare
Hello to all chess lovers.
In the following puzzle you don't have to think ahead you have to think back.

It is chance of black to move. What move has white just played ?

At first sight it seems it is impossible to solve since white king is surrounded by a double check everywhere.
You my friend have refreshed my memories. I have seen this problem some 9-10 years ago. And during tournaments me and my friends were discussing it. It so happend that everything got over including speeches and prize distribution and we were still on the same board trying to solve it up. Finally we had the solution.. God I miss those days...
Now since I have already seen and solved this puzzle, I wouldnt spoil the fun rather just give a hint.

Ok. since this needs a bit of different approach, try to add something more on board, carefully observe the pawn on g-file. Try to guess how it can come on g3 square. Once you can place this, its very easy.

X-Engineer

Branch Unspecified
23 Feb 2012
Try to guess how it can come on g3 square
@simplycoder..As my approach the pawn on g3 came from g4 or f4 or h4(As black is on the other side)
But still could'nt get further on this approach.

adding something ,i tried but couldnt even go more ..as there were n number of possiblities.

circularsquare

Branch Unspecified
24 Feb 2012
simplycoder
Ok. since this needs a bit of different approach, try to add something more on board, carefully observe the pawn on g-file. Try to guess how it can come on g3 square. Once you can place this, its very easy.
Very subtle hint . You haven't given too much away yet your hint is valuable.
One more subtle hint is that the solution needs the use of a move which is not carried out too frequently in chess. The move has a special name. 😉
X-Engineer
@simplycoder..As my approach the pawn on g3 came from g4 or f4 or h4(As black is on the other side)
But still could'nt get further on this approach.

adding something ,i tried but couldnt even go more ..as there were n number of possiblities.
you are on a good track keep it up.

I myself could never solve this one.

X-Engineer

Branch Unspecified
24 Feb 2012
The move has a special name
I guess it should be
`https://en.wikipedia.org/wiki/En_passant`
there should be white pawn at g2 ,which moves forward by 2 step by white and finally black crosses by en passant..Is it.?? just a rough guess

RVignesh

Branch Unspecified
24 Feb 2012
i guess the en passant is not possible because for that the pawn has to move two steps and seeing the current set up it seems impossible. The pawn on g3 must have come there by replacing some other white piece . Since white king cannot move so the only possible move left ismoving the other piece

X-Engineer

Branch Unspecified
24 Feb 2012
En passant...not possible??

What about the possiblity i had mentioned in the previous post...???is it??

RVignesh

Branch Unspecified
24 Feb 2012
ya when pawn moves from g2 it is possible but i guess in the present case at g2 there will be a black piece and not white so there is no chance for the special move.

X-Engineer

Branch Unspecified
24 Feb 2012
in the present case at g2 there will be a black piece and not white
How you confirm that sort of thing..

Also consider ,if non of the other black pieces were present ,g2 becomes the orginal white pawn position ,taking some n-(n-(n-......))))))).....)) steps back...

What if all those black Queen and bishops came after the pawn moved...(just thinking in all possible ways)

X-Engineer

Branch Unspecified
24 Feb 2012
@circularsquare:::Is there a permanent answer for this ..or are u driving us crazyyyyyyyy😀

RVignesh

Branch Unspecified
24 Feb 2012
your point accepted. But we dont know the initial positions of black and white so we cannot assume en passant .

X-Engineer

Branch Unspecified
24 Feb 2012
initial positions of black and white
Always the numbering is taken from the white position...So the rows 1 and 2 should be white and rows 7 and 8 should be black.

lovejeet

Branch Unspecified
24 Feb 2012
X-Engineer
How you confirm that sort of thing..

Also consider ,if non of the other black pieces were present ,g2 becomes the orginal white pawn position ,taking some n-(n-(n-......))))))).....)) steps back...

What if all those black Queen and bishops came after the pawn moved...(just thinking in all possible ways)
read the question carefully. it says,
"It is chance of black to move."
which means black hasn't moved yet. that means, last move was of white. so any pawn move won't be accepted since it's not legal for the pawns to suicide. 😛

Jyothi Jo

Branch Unspecified
24 Feb 2012
Firstly the pawn is in f4 position, there was a knight at h1 position.
First knight is moved from h1 to g3 and so the pawn on f4 kills the knight on g3 and get a chance to move .

silverscorpion

Branch Unspecified
24 Feb 2012
Ah!! Eurekaaaaaaaaaaaaaa!!

White King was initially at f5, and there was a white pawn at g2 and a black pawn at f4.

So, probably the move before that was Bh3+, for which white replies with g2 -> g4 blocking the bishop.
black moves f4 X g4 using en-passant capture..
and so white, now faced with a double discovered check, moves f5 -> e5

That's how the king came to that square.

Wow!! Very difficult indeed.. Thanks very much simplycoder for the hint 😀
Really a good one!! 😀

lovejeet

Branch Unspecified
24 Feb 2012
silverscorpion
Ah!! Eurekaaaaaaaaaaaaaa!!

White King was initially at f5, and there was a white pawn at g2 and a black pawn at f4.

So, probably the move before that was Bh3+, for which white replies with g2 -> g4 blocking the bishop.
black moves f4 X g4 using en-passant capture..
and so white, now faced with a double discovered check, moves f5 -> e5

That's how the king came to that square.

Wow!! Very difficult indeed.. Thanks very much simplycoder for the hint 😀
Really a good one!! 😀
ahhhhhh......
the question says:-
"It is chance of black to move."
which means black hasn't moved yet. that means, last move was of white.
so how can black capture white's pawn if it hasn't moved yet???

silverscorpion

Branch Unspecified
24 Feb 2012
^^ Backtrack the moves..

Yes, it's black's turn to move now. Which means, the last move was made by white.
And, since the king is the only white piece in the board, it follows that the last move made by white must be a king move. Now, from where can you move the king to the present square? Every other square has double check.. So, even if you manage to cover for one black piece using some other white piece, there is another black piece threatening the king.. So, the correct solution should cover both pieces in a certain square..

Now, for the solution. If the king was in f5, it would have been attacked by both queen and the bishop. And since it is hinted that en-passant capture is used, there are 2 pawns involved - one white and one black. The black pawn is still on the board. It must have been at f4 or g4 prior to that capture. It makes sense to assume it was in f4, as it covers the check from the queen.

Now, for the bishop, you can say that the bishop came there in the first place, from some other square, making a check. The white blocks the bishop using the g2 pawn. Now, both pieces are covered, and the white king is not in check. Then, black captures the g4 pawn, and the white king is in double check, and hence, moves from f5 to e5. Now it's black's turn to move, as the question says..

so the answer is, white's previous move was Kf5-e5 or King from f5 to e5.

i hope it's clear.

lovejeet

Branch Unspecified
24 Feb 2012
silverscorpion
^^ Backtrack the moves..

Yes, it's black's turn to move now. Which means, the last move was made by white.
And, since the king is the only white piece in the board, it follows that the last move made by white must be a king move. Now, from where can you move the king to the present square? Every other square has double check.. So, even if you manage to cover for one black piece using some other white piece, there is another black piece threatening the king.. So, the correct solution should cover both pieces in a certain square..
that's what m trying to say. according to me, the question is wrong, since if there is an en-passant, then again the last move is by black, which contradicts that black has to move.

silverscorpion

Branch Unspecified
24 Feb 2012
Black made the en-passant capture, and white replied with Ke5, now it's again black's turn to move. The last move that was made was Kf5->e5.

I don't know how else to put it.. But I think the question is correct and I believe the answer I gave is also correct..

Jyothi Jo

Branch Unspecified
24 Feb 2012
silverscorpion
^^ Backtrack the moves..

Yes, it's black's turn to move now. Which means, the last move was made by white.
And, since the king is the only white piece in the board, it follows that the last move made by white must be a king move. Now, from where can you move the king to the present square? Every other square has double check.. So, even if you manage to cover for one black piece using some other white piece, there is another black piece threatening the king.. So, the correct solution should cover both pieces in a certain square..

Now, for the solution. If the king was in f5, it would have been attacked by both queen and the bishop. And since it is hinted that en-passant capture is used, there are 2 pawns involved - one white and one black. The black pawn is still on the board. It must have been at f4 or g4 prior to that capture. It makes sense to assume it was in f4, as it covers the check from the queen.

Now, for the bishop, you can say that the bishop came there in the first place, from some other square, making a check. The white blocks the bishop using the g2 pawn. Now, both pieces are covered, and the white king is not in check. Then, black captures the g4 pawn, and the white king is in double check, and hence, moves from f5 to e5. Now it's black's turn to move, as the question says..

so the answer is, white's previous move was Kf5-e5 or King from f5 to e5.

i hope it's clear.

Can you explain how bishop came to that h3 position? because if it is already in that position white king doesn't dare to take step to be in f5 ,incase if first white king is in f5 and how does the bishop come in h3 because it has only two paths to come into h3 one path is covered by white pawn and the other path is covered by white king

silverscorpion

Branch Unspecified
24 Feb 2012
Oh, yeah!! Didn't notice that. Then it just follows that the white pawn was not in g2 but in g3, initially. Right?
Now it will be possible for the black bishop to come to h3 from f1.
As for why black doesn't capture the white pawn at g2, I don't have an answer. Just a different approach, I guess.. 😀

Jyothi Jo

Branch Unspecified
24 Feb 2012
I'm eager to know whether my answer to the question is right or wrong? no one is even replying ? 😔

X-Engineer

Branch Unspecified
24 Feb 2012
Then it just follows that the white pawn was not in g2 but in g3, initially.
Then how will it proceed...??
What happens to the white pawn at g3 and how will the black pawn reach g3..

X-Engineer

Branch Unspecified
24 Feb 2012
@jyothi
Firstly the pawn is in f4 position, there was a knight at h1 position.
First knight is moved from h1 to g3 and so the pawn on f4 kills the knight on g3 and get a chance to move .
where is the King at that positions??

lovejeet

Branch Unspecified
24 Feb 2012
Jyothi Jo
I'm eager to know whether my answer to the question is right or wrong? no one is even replying ? 😔
yah, that move is conceptually right, but logically it can't be digested. why would white move his knight to get it captured instead of capturing the black's rook??

Jyothi Jo

Branch Unspecified
25 Feb 2012
lovejeet
yah, that move is conceptually right, but logically it can't be digested. why would white move his knight to get it captured instead of capturing the black's rook??
As mentioned in question its the chance for black to move and so if white kills rook then white get a chance to move, moreover my answer only matches with knight and none other pieces just check it once.

Jyothi Jo

Branch Unspecified
25 Feb 2012
X-Engineer
@jyothi

where is the King at that positions??
King is in its same position.

simplycoder

Branch Unspecified
25 Feb 2012
Ok. You guys are close to it.
Here is what you can think on..
White King is placed on a square where there is no check and that square is definitely not e5.
Now some how it is forced to e5. Where the move previous was a check and none of the pieces from the image moved(If they would have, they wouldnt have had the same position as of now.)

Now I think it would be pretty simple.

silverscorpion

Branch Unspecified
06 Mar 2012

Mr.Don

Branch Unspecified
06 Mar 2012
The white had played from f6 to e5.

circularsquare

Branch Unspecified
17 Mar 2012
The solver must deduce White's last move. At first blush, there seems to be no solution: on any square from which the white king could have moved, it would have been under a seemingly impossible double check; however, thinking more we can discover that if white king moved from f5, then the black move before that could be pawn f4xg3, taking the white pawn on g4 en passant. Thus before f4xg3, white must have played pawn g2-g4. But what did Black move before that? The white king on f5 was under check by the bishop on h3 and there was a white pawn on g2. The only possibility is that black moved knight g4-e5 with discovered check. Therefore White's last move was king f5 takes knight on e5. (The entire sequence of moves is thus 1...Ng4-e5 discovered check 2.g2-g4 f4xg3 double check 3.Kf5xe5.)
Note that in this example the actual next move is essentially irrelevant; Black has a choice of several relatively trivial ways of delivering instant checkmate. (E.g. f3-d5#, d6-d5#, etc.).
One might ask: "If the white pawn was on g2 from the start of the game, how could the Black Queen come to be on f3, also a Black Bishop to be on h3? Is this problem valid?" The problem is indeed valid. The initial position has to be legal, but not particularly reasonable. That the Black Queen and Bishop were en prise in the initial position may be disappointing to some, it does not invalidate the problem.