Author |
Topic: Black's Last Move? (Read 1531 times) |
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender: 
Posts: 4489
|
 |
Re: Black's Last Move?
« Reply #25 on: Sep 4th, 2003, 8:32pm » |
 Quote  Modify
|
Quote:| Then there must have been a white piece between him and the rook. It must have been a knight that moved to h2, and the black king knocked it off on his final turn. |
|
You are getting there, visitor.
Wowbagger proved that if Black's last move was Kg1-h2, White's previous move must have been 0-0-0
(that is, castles queenside). However, the resulting position is illegal as the Black king is now in a cage
formed by the White king at e1 (which hasn't moved) and the pawns on g2 and g3. He wrongly concluded
that the original board position is illegal. All we can conclude from his analysis is that Kg1-h2 was NOT
Black's last move, and that we do not need to retract 0-0-0 for White. Now, with no White king at e1,
there is no cage.
|
| « Last Edit: Sep 4th, 2003, 10:23pm by ThudnBlunder » |
 IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
BNC
Uberpuzzler
Gender:
Posts: 1732
|
|
Re: Black's Last Move?
« Reply #26 on: Sep 5th, 2003, 4:27am » |
Quote Modify
|
IS the game based on "current" chess rules? That is, when a black pawn reaches row 1, can it change to a white piece, or just a black piece?
|
|
IP Logged |
How about supercalifragilisticexpialidociouspuzzler [Towr, 2007]
|
|
|
wowbagger
Uberpuzzler
 
Gender:
Posts: 727
|
|
Re: Black's Last Move?
« Reply #27 on: Sep 5th, 2003, 5:05am » |
Quote Modify
|
on Sep 4th, 2003, 2:09pm, visitor wrote:Let's say there was a bishop on e1 when the black king moved in (d3,e2,f1,g1). Bf2...Kh2.
Be3 where it was knocked off by some black piece. Nxe3
Black moved its only other piece somewhere. white Nf1. |
|
Check!
on Sep 4th, 2003, 8:32pm, THUDandBLUNDER wrote:
You are getting there, visitor.
Wowbagger proved that if Black's last move was Kg1-h2, White's previous move must have been 0-0-0
(that is, castles queenside). However, the resulting position is illegal as the Black king is now in a cage
formed by the White king at e1 (which hasn't moved) and the pawns on g2 and g3. He wrongly concluded
that the original board position is illegal. All we can conclude from his analysis is that Kg1-h2 was NOT
Black's last move, and that we do not need to retract 0-0-0 for White. Now, with no White king at e1,
there is no cage. |
|
So the last move by Black was not Kg1-h2, which implies that his last move was not by his King - or am I mistaken here once again? Anyway, any other pieces he might have moved would still be on the board, as there is no legal move off of the board.
on Sep 5th, 2003, 4:27am, BNC wrote:| IS the game based on "current" chess rules? That is, when a black pawn reaches row 1, can it change to a white piece, or just a black piece? |
|
Oh, c'mon! Not again!? 
Please spare me from having to rant about the difference between history-of-the-rules riddles and chess riddles. 
|
|
IP Logged |
"You're a jerk, <your surname>!"
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #28 on: Sep 5th, 2003, 5:05am » |
Quote Modify
|
BNC, all retro puzzles are based on standard chess rules. Here, promotion is not an issue. But castling is.
|
| « Last Edit: Sep 5th, 2003, 5:08am by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
wowbagger
Uberpuzzler
Gender:
Posts: 727
|
|
Re: Black's Last Move?
« Reply #29 on: Sep 5th, 2003, 5:14am » |
Quote Modify
|
on Sep 5th, 2003, 5:05am, THUDandBLUNDER wrote:| BNC, all retro puzzles are based on standard chess rules. |
|
That's reassuring. 
|
|
IP Logged |
"You're a jerk, <your surname>!"
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #30 on: Sep 5th, 2003, 6:23am » |
Quote Modify
|
Quote:| So the last move by Black was not Kg1-h2, which implies that his last move was not by his King - or am I mistaken here once again? |
|
What is the notation for capturing?
|
|
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #31 on: Sep 5th, 2003, 7:13am » |
Quote Modify
|
Quote:Let's say there was a bishop on e1 when the black king moved in (d3,e2,f1,g1). Bf2...Kh2.
Be3 where it was knocked off by some black piece. Nxe3
Black moved its only other piece somewhere. white Nf1. Black moves that other piece to c1, where it's knocked off by the white king. Then black Kg1, Nh2, Kxg2. |
|
I will just say that this is.......wrong.
I won't say anymore as I don't want to upset Icarus - especially now that he is a moderator. 
|
|
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
visitor
Guest
|
I really should give up on these chess puzzles, but I'll take one more stab at it
The castling took place earlier. Black moved a rook to e1 (or a white bishop sat there, which the black rook knocked off after the king moved into position). He safely moves his king in to g1. From that point it's rook to f1, white Ne3, Kh2, Nxf1, Kg1, Nh2, Kxg2. (doesn't make much sense, but it's legal, I think)
|
|
IP Logged |
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #33 on: Sep 5th, 2003, 7:19am » |
Quote Modify
|
Quote:| Then there must have been a white piece between him and the rook. It must have been a knight that moved to h2, and the black king knocked it off on his final turn. |
|
This analysis seems OK to me.
Quote:| Sorry, my solution doesn't work. It doesn't leave black with any valid move on its turn right before the knight moved to h2. Back to the drawing board. |
|
But here you seem to overlook the fact that the White knight may, indeed must, have captured something.
|
| « Last Edit: Sep 5th, 2003, 10:07pm by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
wowbagger
Uberpuzzler
Gender:
Posts: 727
|
|
Re: Black's Last Move?
« Reply #34 on: Sep 5th, 2003, 7:43am » |
Quote Modify
|
on Sep 5th, 2003, 6:23am, THUDandBLUNDER wrote:
What is the notation for capturing? |
|
Boy, do I feel stupid!
Next try:
-1. ... Kg1xh2
-2. Nf1xh2+ Rh8xQh2 (or -2. ... Ng4xQh2)
How's that?
|
| « Last Edit: Sep 5th, 2003, 7:45am by wowbagger » |
IP Logged |
"You're a jerk, <your surname>!"
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #35 on: Sep 5th, 2003, 8:21am » |
Quote Modify
|
Eureka! You got it, wowbagger. And I thought that this puzzle was Easy.
(It is not necessary for the Black piece to capture anything on h2.)
I wonder how visitor is getting on with his bishops. 
|
|
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
If we started with the position below, the game would go:
1. Nh1 Rh2
2. Nxh2+ Kxh2
In order to arrive at the original puzzle position, all the moves are forced.
|
| « Last Edit: Sep 5th, 2003, 10:30am by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
Sir Col
Uberpuzzler
impudens simia et macrologus profundus fabulae
Gender:
Posts: 1825
|
|
Re: Black's Last Move?
« Reply #37 on: Sep 5th, 2003, 9:07am » |
Quote Modify
|
But surely after white knight moves to h1, the rook or king would take it?
|
| « Last Edit: Sep 5th, 2003, 9:10am by Sir Col » |
IP Logged |
mathschallenge.net / projecteuler.net
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #38 on: Sep 5th, 2003, 9:18am » |
Quote Modify
|
Quote:| But surely after white knight moves to h1, the rook or king would take it? |
|
AAAARRGH!!!
Aren't threads meant to be read from the beginning rather than from the end?
|
| « Last Edit: Sep 5th, 2003, 11:32am by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
wowbagger
Uberpuzzler
Gender:
Posts: 727
|
|
Re: Black's Last Move?
« Reply #39 on: Sep 5th, 2003, 9:22am » |
Quote Modify
|
|
|
IP Logged |
"You're a jerk, <your surname>!"
|
|
|
Sir Col
Uberpuzzler
impudens simia et macrologus profundus fabulae
Gender:
Posts: 1825
|
|
Re: Black's Last Move?
« Reply #40 on: Sep 5th, 2003, 10:06am » |
Quote Modify
|
on Sep 5th, 2003, 9:18am, THUDandBLUNDER wrote:
AAAARRGH!!! |
|
Temper, temper!
I wasn't serious about suggesting that the king or rook should have taken the knight, after all it would have been much better for the rook to have put the white king in check by moving to c8. So why didn't black do that?
|
| « Last Edit: Sep 5th, 2003, 10:07am by Sir Col » |
IP Logged |
mathschallenge.net / projecteuler.net
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #41 on: Sep 5th, 2003, 10:53am » |
Quote Modify
|
Quote:| I wasn't serious about suggesting that the king or rook should have taken the knight, after all it would have been much better for the rook to have put the white king in check by moving to c8. So why didn't black do that? |
|
Yes, I have to hand it to you, Sir Col, that's very subtle.
After the fingerfehlur Nh1, rather than immediately capture the errant knight on h1, you would calmly play the zweischenzug Rc8+, while defying anybody to utter the old adage "Patzer sees a check, gives a check." 
|
| « Last Edit: Sep 5th, 2003, 7:30pm by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
wowbagger
Uberpuzzler
Gender:
Posts: 727
|
|
Re: Black's Last Move?
« Reply #42 on: Sep 5th, 2003, 11:58am » |
Quote Modify
|
T&B, I suppose you mean fingerfehler and zwischenzug.
|
|
IP Logged |
"You're a jerk, <your surname>!"
|
|
|
ThudnBlunder
wu::riddles Moderator
Uberpuzzler
The dewdrop slides into the shining Sea
Gender:
Posts: 4489
|
|
Re: Black's Last Move?
« Reply #43 on: Sep 5th, 2003, 12:10pm » |
Quote Modify
|
Quote:| T&B, I suppose you mean fingerfehler and zwischenzug. |
|
Yes. Thanks, wowbagger.
Trust me to check my spelling by choosing the ONLY site on the Web which spells them both wrongly!
www.theopenfile.com/articles/lingo.htm
|
| « Last Edit: Sep 6th, 2003, 9:13pm by ThudnBlunder » |
IP Logged |
THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
|
|
|
towr
wu::riddles Moderator
Uberpuzzler
Some people are average, some are just mean.
Gender:
Posts: 13730
|
|
Re: Black's Last Move?
« Reply #44 on: Sep 6th, 2003, 5:19am » |
Quote Modify
|
how did the king ever get to g1 in the first place?
|
|
IP Logged |
Wikipedia, Google, Mathworld, Integer sequence DB
|
|
|
Sir Col
Uberpuzzler
impudens simia et macrologus profundus fabulae
Gender:
Posts: 1825
|
|
Re: Black's Last Move?
« Reply #45 on: Sep 6th, 2003, 6:17am » |
Quote Modify
|
That was my initial reaction when I saw the problem, but as T&B has said since, and highlighting my ignorance over these types of problem, "Retrograde Analysis is a genre of chess problems where the legality of the position is a key element.
A position is legal if it can be reached through a legal chess game (no matter how weird)."
It is possible IF... the black king was on d3 and moved diagonally to f1, but this would depend of two things: (i) there was a white piece, like a bishop, on e1 (blocking the rooks line of attack on row 1, and, (ii) the white pieces sit back and do nothing troublesome whilst the black king moves into position.
|
|
IP Logged |
mathschallenge.net / projecteuler.net
|
|
|
|
RIDDLES SITE
WRITE MATH!
Home 
Help 
Search 
Members 
Login 
Register
Reply
Notify of replies
Send Topic
Print
Remove