Illegal Position Contest!

try to find it for 5857

DefenderPug2, that's meant for you.  It's #5856 now, and it was posted just for you. Why is it illegal? It's not totally obvious, but it's not too hard either.

yep

The definition is on the first post of the topic….I made it…..

I'm wondering whether you understand what DefenderPug2 has been asked to do.

But to answer your request, White got the pawn formation on the queen side by making eight captures by pawns of the eight black men missing from the final position.

What I gave you was the only way that pawn formation could be achieved, without saying whether or not the position is legal.

I don't see a definition there. It would look like "A position is considered friendly when _______" and you have to fill in the blank. Since the challenge is to find the friendliest position, you also need to explain how to determine whether one position is more friendly than another.

i can get really far, but the problem is, though black has JUST enough pieces to capture, blacks h pawn cant promote

thats a proof game if white doesnt have c1 bishop btw

so, its illegal as blacks h pawn needs 1 more capture than available to promote

Yes. Now you have done what DefenderPug2 was being asked to do.

In #5881, December_TwentyNine misstated the question put to DefenderPug2. The question was "Why is it illegal?" not "Is it legal or illegal?"

By the way, you had the right idea with your explanation, but it was incomplete. The black h-pawn could have promoted, but then the g-pawn would lack the one capture needed to promote.

It is possible.

oh yeah

anyway black misses a capture

(thatd be via rg3 and rh2 or any other pieces on those squares)

thats black to move

I told DefenderPug2 that proving illegality of #5856 is not too hard. You did it by giving a possible proof game, which is one way, but it can be proven without any trial proof games. Here's one proof that's not too hard:

The white pawns need eight captures to get into place, and Black is missing eight men, so every capture White made was by a pawn moving toward the queen side. What happened to the black fgh pawns? The f-pawn could be at d5 after making two captures, and the pawn at d6 made one capture, which only leaves Black two captures to get the g and h-pawns promoted to pieces to be captured by the white pawns. But those two pawns need to make three captures to promote on h1, so one of them is an abducted pawn. (An abducted pawn is one that did not promote, was not captured, and is no longer on the board. Any position that has one is illegal.)

I’m so confused….

Btw I beat a 800 rated player. We met in 4 player chess teams. Didn’t know I had what it takes. It was unrated. So unfortunately, I did not make a crater in his rating.

im also a beginner and i solved it (almost)

The discussion we've had of it here shows that EvinSung came up with one of the "good" illegal positions: not immediately obvious to an experienced solver, but not too hard for a beginner to solve.