NinjaBear, your first position is illegal because the rook couldn't have moved to the other side of the board.
Not according to MRO314, see post #3. It appears the king and queen can move to the c-file and back for the rook to escape (OR the king can castle).
you i was thinking about these types of puzzles before... savage class
very good puzzles
Legal or illegal?
Well, let's see... White starts with axb3, e3 and bxc4, letting the Bishop go to b1. The White Rooks escaped through the a-file. Black had to play a6 before b6 to get the Bishop to b8, so b6, a6, axb5 are the pawn moves on the Queenside. Before axb5, the Black Bishop had to go to a4. Then Black played Bb3, Ra3, and Ba4. Black played Rc3 and Bb3, allowing the Black King to pass through a3. White's Bishop went to f4. Black's King went to White's first rank and hid on e2 as White's went up to Black's with Rh8 and Ng8 there, letting White's King run through g7 to b7. Keep in mind that the Black Knight can only move to g8 after White's King is on g7 or it prevents Ka6. Black then moved the Knight and Rook to their spots as well as White's King. White maneuvered the White Rook to a3 and Knight to a1 and the Black King ran to its spot. Then white played b3. As far as I can tell, it's legal... How much am I missing?
Legal or illegal?
I think this one might be possible, though if it is, its bloody difficualt!
anyhow, here is my best attempt, maybe it will help others work it out:
If it is white to move, this is legal. If this was black to move, this is not legal.
I disagree. White could bring his knight out, then black could, then white could bring a second knight out, then black could bring his knight back in. White brings a knight in, black puts a knight out, white puts a knight out, black brings his knight in, white brings a knight in black puts a knight out, white brings a... Yeah this isn't working out.
yeah, that is genious.
BAHAHAHA!!
Reply to Fiveofswords: Still black's move
Whoa. Thats difficult...I cant tell
The only way almost all positions can be legal or illegal depending on whose move it is is if someone is in check. Thats really the only possiiblity. Its just too easy to lose a move with most of the pieces, the only other possible exception is if its near the starting position and all of the pieces that can lose a tempo have never been alle to move yet(still smothered by pawns)...
Not always. For example, here's the position I posted before (post #16).
This position is legal if it is black to move, but illegal if it was white to move. If it was white to move, what was black's move before it? It couldn't be a king move, so it would have to be a pawn move. It couldn't be made by e7, f7, or g7 because they are at their normal starting squares. It couldn't be fxg6, because then the pawn would be at f6 and there is no way the pawn could get there. If it was hxg6, that means the pawn was at h6. The only way the white bishop could get to h8 is by promotion. So there would have to be a pawn at g6, then gxh7 and then h8=B. But then, there's no way the rook could have gotten to h7. So this position is illegal if it was white to move.
hic2482w's position (25th post of the thread) is a composition by Plaksin. I believe the stipulation is "mate in three" but one "should" also provide the necessary retro analysis :p
Here are some more:
This position would be legal if it was black to move, but illegal if if was white to move
This is illegal no matter who's move it is impossible because there is no way the bishop could have gone to h8 as pawns can't move backwards and g7 is blocked!
A promoted pawn could make that bishop. Therefore legal for black, illegal for white is a correct analysis.
However, if the board is flipped, ie. to view the board from the perspective that the white king sits on d1, this is legal for white and illegal for black
Well that didn't work. If anyone is confused as to which puzzle I am referring, check the second puzzle in post #16 from pompom
Nice topic to try discover true or false
You would probably enjoy this famous puzzle by Raymond Smullyan. Assuming this position was reached in a legal game, we know for certain that white has a mate in two, but not how to achieve it.
NinjaBear, your first position is illegal because the rook couldn't have moved to the other side of the board.