Illegal Position Contest!

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Jahoho

#4729 or # 4788, from n9531l1 : It is  illegal because: 1. Remaining white pawns have performed at least three captures to reach their current positions. [e.g. fxg, bxc, exd] This is legal for their are three black pieces missing 2. The seven black pawns from c-file up to h-file must have done at least seven captures of white pieces. This is legal as well, for their are seven white pieces missing [ e.g. gxh, fxg exf, dxexf, bxc, cxd ] So, all captured white pieces must have been taken by black pawns! 3. But one of these seven white pieces is a white pawn, and in case of the white a-pawn, then it was captured by a black b-pawn. But the black b-pawn captured to the c-file [see 2.], so the black a-pawn needed to capture an white piece number eight to reach the b-file first. But there are still nine white pieces... If it wasn't the white a-pawn which has been captured among the seven black captures, the white a-pawn has moved to the c-file by two captures, which totals then to at least four black pieces captured by white. But there are still thirteen black pieces .... So the position is illegal.  But probably there is shorter argumentation?

n9531l1

That's correct. I think natureexplorer was also about to find it. It can be explained a little more briefly. White's three available captures were pawn captures to make three pairs of doubled pawns. Black's seven available captures were all made by six pawns, one each by bcefg pawns and two by the d-pawn, with all six ending on the c through h files. So neither side's a-pawn was captured or could have promoted, but White's a-pawn has disappeared (illegally) from the board.

n9531l1
Mikey383 wrote:

I think this position [#4764] is illegal if it's white to move. 

No one has tried to answer my questions at #4773 about this legal position, so I'll ask them again. Is the position still legal if a black queen is placed at f6? Does who has to end up with the move make a difference in the legality?

I'll wait a while for a response, and then give my answers, to see if anyone disputes them.

 

Ilampozhil25
n9531l1 wrote:

That's correct. I think natureexplorer was also about to find it. It can be explained a little more briefly. White's three available captures were pawn captures to make three pairs of doubled pawns. Black's seven available captures were all made by six pawns, one each by bcefg pawns and two by the d-pawn, with all six ending on the c through h files. So neither side's a-pawn was captured or could have promoted, but White's a-pawn has disappeared (illegally) from the board.

wait. what about my logic in which 3 captures by white pawns= white should get the pawn to h6 without captures which is impossible?

theres  a white pawn on h6 right?

Ilampozhil25

and before you say, "but the original black h pawn can get captured"

black has all 8 pawns

you cant promote or capture them

Ilampozhil25

#4795 and #4791 and #4797-4799

 

n9531l1
Ilampozhil25 wrote:

theres  a white pawn on h6 right?

No, but there's a white pawn on h3.

n9531l1

Here is Mikey383's #4764 position with a black queen added at f6. Is the modified position legal if it's White to play?  What if it's Black to play?

 

OrphanGenerator
ThebestA9player wrote:

white to move

This is possible because of 1. Nf3 e6 Ng1

KMMCS88
epicusernamehere wrote:
ThebestA9player wrote:

white to move

This is possible because of 1. Nf3 e6 Ng1

After those moves, it's Black to move.

KnockKnockItstheFBI

 

n9531l1
KnockKnockItstheFBI wrote:

[Position with nine white pawns]

I can see you tried hard to create an illegal position that would make us think it might be legal without a careful analysis. This one was not too successful, but keep trying.

Sameer_chess-player
n9531l1 wrote:
KnockKnockItstheFBI wrote:

[Position with nine white pawns]

I can see you tried hard to create an illegal position that would make us think it might be legal without a careful analysis. This one was not too successful, but keep trying.

could you stop saying the same thing over and over?

Sameer_chess-player
n9531l1 wrote:
Sameer_chess-player wrote:

and this is legal as white to move. nobody ever said black had to be able to castle.

I'm not sure what the point of this one is. Your final position is the same as the position you had after move 1.

oh i mean this



Sameer_chess-player

um......

 

n9531l1
Sameer_chess-player wrote:

could you stop saying the same thing over and over?

Probably not.

Sameer_chess-player

 

Mikey383
n9531l1 wrote:
Mikey383 wrote:

I think this position is illegal if it's white to move. 

I couldn't see any reason to think it would be illegal.

 

If black just moved and it was white's turn in the position

n9531l1
Mikey383 wrote:
n9531l1 wrote:
Mikey383 wrote:

I think this position is illegal if it's white to move. 

I couldn't see any reason to think it would be illegal.

 

If black just moved and it was white's turn in the position

Right. My proof game ended in that position with White to move. It's a legal position that can be reached with either White or Black to move, whichever you want.

Fire