legal AND illegal positions

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NinjaBear

I've recently become interested in solving puzzles where you determine if a position is legal or not. For example, is this position legal?                                                                                                                                                      

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Can someone produce a position that is legal AND illegal (depending on if the puzzle is white or black to move)? I should also add that neither side is in check.

 

Have fun...

 

JOH

Pebandon

Two black-colored bishops. No way for White to promote a Pawn as Black's Pwan wall isn't broken.

MRO314
MRO314

NinjaBear

Thank you MRO314. It appears that it is just the definition of a stalemate!

nqi

Illegal. White would have had to move one of his queens to either c7 or b6 while the other was already at the other of those squares, meaning that Black would have had to move while in stalemate.

Blackadder
nqi wrote:

Illegal. White would have had to move one of his queens to either c7 or b6 while the other was already at the other of those squares, meaning that Black would have had to move while in stalemate.


pompom
NinjaBear wrote:

I've recently become interested in solving puzzles where you determine if a position is legal or not. For example, is this position legal?                                                                                                                                                      

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Can someone produce a position that is legal AND illegal (depending on if the puzzle is white or black to move)? I should also add that neither side is in check.

 

Have fun...

 

JOH


Yes, here is an example:

If it is white to move, this is legal.  If this was black to move, this is not legal.

Apoapsis

legal or illegal?

pompom
xbigboy wrote:

legal or illegal?

 

 


it's obviously illegal because there are no kings on the board.

NinjaBear

I'm finding this humorous.

NinjaBear
pompom wrote:
NinjaBear wrote:

I've recently become interested in solving puzzles where you determine if a position is legal or not. For example, is this position legal?                                      

 

Can someone produce a position that is legal AND illegal (depending on if the puzzle is white or black to move)? I should also add that neither side is in check.

 

Have fun...

 

JOH


Yes, here is an example:

 

 

If it is white to move, this is legal.  If this was black to move, this is not legal.

 


Interesting.

MugglesMan

Elegant solution in post #8 pompom.  It made me smile.

sgt_pepper
pompom wrote:
Yes, here is an example:

 

 

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.

pompom
sgt_pepper wrote:
pompom wrote:
Yes, here is an example:

 

 

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.


yeah, the knights can't lose a tempo (because it goes from a light square to a dark square and a dark square to a light square) and the rooks have only one square to go to.

pompom

Here are some more:

Georgewang
pompom wrote:

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!

Tenna

That bishop could have been a promoted pawn.

pompom

Yes, I just said that the bishop was promoted.

diemking

very interesting topic