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Illegal Position Contest!

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Avatar of Night-Rider_chess8987
Night-Rider_chess8987
Sep 4, 2021
0
#5601
n9531l1 wrote:
Night-Rider_chess8987 wrote:
n9531l1 wrote:
Night-Rider_chess8987 wrote:

 

We haven't seen the spammers come around for a while. I guess it's time.

bruh the only thing I am doing is posting 

That's what spammers do. I don't blame them. Their personalities don't permit them to stop disrupting some thread or other.

ok

Avatar of MARattigan
MARattigan
Sep 4, 2021
0
#5602
n9531l1 wrote:
MARattigan wrote:
n9531l1 wrote:
MARattigan wrote:

Easy (I was trying to do something else).

By "Easy" do you mean it's easy to prove illegal, or that it has an easy proof game and doesn't belong in this thread?

Easy to prove illegal. (But I'd be interested to see a proof game.)

This could be a  good position for the Shortest Proof Game thread. My easy unshortened 40-move game would be a start for it there.

 

Well done.

Not my first duff proof and no doubt not my last. (I counted the captures by the pawns as 2+3+4 instead of 1+2+3.)

All comes down to the old saw, "there are three kinds of mathematician - those that can count and those that can't".

Avatar of Night-Rider_chess8987
Night-Rider_chess8987
Sep 4, 2021
0
#5603
Night-Rider_chess8987 wrote:

an illegal post

another illegal post

another illegal post

my last illegal post

is this right?

Avatar of MyNameIsNotBuddy
MyNameIsNotBuddy
Sep 4, 2021
0
#5604

 

Avatar of MARattigan
MARattigan
Sep 4, 2021
0
#5605

How many KQQK positions where the black king is in check from both queens are not illegal?

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5606
MARattigan wrote:

How many KQQK positions where the black king is in check from both queens are not illegal?

Without thinking too much I can give well over 600 such positions.

Avatar of MARattigan
MARattigan
Sep 4, 2021
0
#5607

I worked out the exact number a couple of years ago. I wanted to check how accurate the published Nalimov stats for the ending were if you assume only legal positions. What do you make it?

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5608

Rather than looking for an exact number, I'll go along with the one you worked out. What was it?

Avatar of EvinSung
CM EvinSung
Sep 4, 2021
0
#5609

 

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5610
EvinSung wrote:

#5660

This one looks illegal to me. If the white bishop on g8 were on f8, it would be a legal position.

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5611
December_TwentyNine wrote:

But hunnie if that was the case then she'd have 2 dark square bishops.

What? No cute explanation involving chess by 5-year-olds?

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5612
December_TwentyNine wrote:

I think you are right. Because if you look more carefully, it IS illegal because White's g and e Pawns haven't moved yet - so the Bishop could have never left it's starting square.

Which IS illegal? The posted position, or the position with the white bishop moved to f8, or both?

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5613

Yes, we're talking about #5660. Would the position be legal if the white bishop on g8 were moved to f8? The pawns on b2 and d2 haven't moved either.

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5614

Here's my proof game with the white bishop on g8 moved to f8.

 

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5615

Now see if you can come up with a valid explanation of why the posted position is illegal.

Avatar of greypenguin
greypenguin
Sep 4, 2021
0
#5616
n9531l1 wrote:
EvinSung wrote:

#5660

This one looks illegal to me. If the white bishop on g8 were on f8, it would be a legal position.

but what about the other pawn? there are not enough captures to get the white pawn past the black ones to promote

Avatar of n9531l1
n9531l1
Sep 4, 2021
0
#5617
greypenguin wrote:
n9531l1 wrote:
EvinSung wrote:

#5660

This one looks illegal to me. If the white bishop on g8 were on f8, it would be a legal position.

but what about the other pawn? there are not enough captures to get the white pawn past the black ones to promote

What other pawn? Which white pawn past which black ones? What are you claiming?

Avatar of EvinSung
CM EvinSung
Sep 4, 2021
0
#5618
n9531l1 wrote:
greypenguin wrote:
n9531l1 wrote:
EvinSung wrote:

#5660

This one looks illegal to me. If the white bishop on g8 were on f8, it would be a legal position.

but what about the other pawn? there are not enough captures to get the white pawn past the black ones to promote

What other pawn? Which white pawn past which black ones? What are you claiming?

i don't know

Avatar of tygxc
tygxc
Sep 5, 2021
0
#5619

#5660
Here is a proof game without the white Rg4.



Avatar of n9531l1
n9531l1
Sep 5, 2021
0
#5620

If no one wants to give an illegality proof for EvinSung's position #5660, I'll do it. It's clear that the original white bishops were captured at home and the ones on the board are promoted pieces. The f2 pawn can march straight down and promote at f8. One capture by Black, of the c7 pawn to d6, along with the capture at home of the c8 bishop by a white knight, lets the c2 pawn promote at c8 without needing any captures. But Black also made a capture by the f7 pawn to g6, which leaves Black with no captures to get the d7 pawn to f6. Thus the position is illegal. tygxc's game shows that the c8 bishop can vacate its home square, but then it's the f7 pawn that's lacking a capture to get to g6.