Illegal Position Contest!

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e7rook

At this point people are spamming in positions like this

and hoping that we won't see the illegal-ity but it's (I guess) not what this thread was designed for. If you actually want to post something obviously illegal I suggest try making a new forum dedicated to something like that (I actually barely put in effort for most of my submissions so yes, this also applies to me. I literally threw in just like, 5 pieces and used 1 minute). (Yes you can upvote or downvote or reply or whatever or call it yap etc) but throwing in zero effort absolutely ruins the purpose of this forum.

n9531l1
e7rook wrote:
I suggest first try it without the 8 kingside pawns then add them later. (#8849)

I wonder if this position was also intended as an example of spamming with an obviously illegal position. (It might take as long as 10 seconds to notice that White has no promoted pieces and the white bishop has illegally moved from f1 to d1.)

MARattigan

But his heart's in the right place.

n9531l1
MARattigan wrote:

But his heart's in the right place.

I believe you're right. He could remove the h2 pawn and post the resulting legal position in the Shortest Proof Game thread. There, the task is to reach the position in the fewest moves.

e7rook
n9531l1 wrote:
MARattigan wrote:

But his heart's in the right place.

I believe you're right. He could remove the h2 pawn and post the resulting legal position in the Shortest Proof Game thread. There, the task is to reach the position in the fewest moves.

There is one?

EndgameEnthusiast2357
n9531l1 wrote:
e7rook wrote:
I suggest first try it without the 8 kingside pawns then add them later. (#8849)

I wonder if this position was also intended as an example of spamming with an obviously illegal position. (It might take as long as 10 seconds to notice that White has no promoted pieces and the white bishop has illegally moved from f1 to d1.)

Could the missing h2 pawn have captured black pieces and promoted to a bishop on a light square to then slide into d1?

daStrwbrry
n9531l1
e7rook wrote:
n9531l1 wrote:
MARattigan wrote:

But his heart's in the right place.

I believe you're right. He could remove the h2 pawn and post the resulting legal position in the Shortest Proof Game thread. There, the task is to reach the position in the fewest moves.

There is one?

If the position without the h2 pawn shows up in the Shortest Proof Game thread, someone there will shorten my 37-move first try. (Forums > Fun With Chess > Shortest-Proof-Game Challenge)

n9531l1
daStrwbrry wrote:
#8856

Here is my try at an illegality proof for this position.

There are no promoted pieces on the board, and the final move is O-O by White. Black's only capture is Pa6xBb5, and White has to cross-capture Pb2xQc3 and Pc2xBb3, to let the a1 rook come out. The h8 rook can't leave the 8th rank via the a-file, since the c8 bishop can't move until Black plays Pb7-b6, and by then there will be a white bishop at a7. So Black has to play Pf7-f5 and Pg7-g6 to get the h8 rook out. One black rook has to reach h6 before there is a white pawn at h5, and the other has to reach h3 before the black knight gets to h4. But then the knight can only get to h4 from f3 or g2, checking White on the way and preventing the final castling.

The game below is a failed attempt. Every piece is in the right place, and White is ready to castle, but castling is illegal because the king has already moved.

daStrwbrry
n9531l1 wrote:
daStrwbrry wrote:
#8856

Here is my try at an illegality proof for this position.

Nicely done! There is one tiny nitpick (black’s h8 rook may have arrived at h3 before g2-g3 was played, but then a6xBb5 hasn’t been played yet so black’s other rook couldn’t have moved over to h6) but apart from that all the details are there.

e7rook
n9531l1 wrote:
MARattigan wrote:

But his heart's in the right place.

I believe you're right. He could remove the h2 pawn and post the resulting legal position in the Shortest Proof Game thread. There, the task is to reach the position in the fewest moves.

Should I do it?

e7rook

Deleted message, click here to view

e7rook

learn and watch 8/1p1ppppp/8/8/8/PkPpP3/1PpPP1P1/RqKB4 w - - 0 1

daStrwbrry

A much more difficult position (compared to my previous one).

SuryaVS
Doesn’t seem illegal but I don’t have to to prove it now. Maybe later?
SuryaVS
time to*
BigDoggProblem
daStrwbrry wrote:

A much more difficult position (compared to my previous one).

Black's a-pawn captured thrice to reach d2. Pf7 captured on e6. This covers all missing white units. White promoted the 3 Kingside pawns, two on f8 and one on g8, capturing N and B on the way.

We can't retract d6 until Bc8 is back, and can't retract g6 until Bf8 is back.

Retract -1.Rd8 h4 -2.Rf8 h5 -3.f7=P h6 -4.f6 h7 -5.fxg5=N Nd5 -6.g4 Nb4 -7.Nc5 Na6 -8.g3 Rb4 -9.Nb3 Rh4 but white cannot retract.

If instead -8...Ra3 -9.Nb3 now Black cannot retract.

Position, as expected, is illegal.

SacrifycedStoat
#19 Weather it is white or black to move, that is easily possible
EndgameEnthusiast2357

Guys can I ask how to you come up with these so random yet so hard positions? They're almost impossible to figure out let alone create.

BishopTakesH7
EndgameEnthusiast2357 wrote:

Guys can I ask how to you come up with these so random yet so hard positions? They're almost impossible to figure out let alone create.

I've found usually I just mess around on a board trying ideas. Then I try and figure out how to make the position unretractable. And there's lots of ways to do that: pieces blocking each other, pieces getting trapped, etc.