Minichess puzzle

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Kirill Kryukov
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Re: Minichess puzzle

Post by Kirill Kryukov »

Brunetti wrote: Mon Mar 03, 2025 12:30 pmwhat is a non-stalemate draw?
It's a draw that is not a stalemate. I.e., the side to move has legal moves to play, and the game never arrives at checkmate if both sides play optimally. In this case, the bare king has the right to move, has legal moves to play, and can force a draw. I guess the first move might be a capture of one of the queens, but can't see what is next. :-)
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Brunetti
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Re: Minichess puzzle

Post by Brunetti »

Kirill Kryukov wrote: Mon Mar 03, 2025 12:55 pm It's a draw that is not a stalemate. I.e., the side to move has legal moves to play, and the game never arrives at checkmate if both sides play optimally. In this case, the bare king has the right to move, has legal moves to play, and can force a draw. I guess the first move might be a capture of one of the queens, but can't see what is next. :-)
Hello,
I don't understand: what other kind of draw could it be? Dead position with at least three sliders and one pawn is impossible, I think.
I can get this one, where the bare king has the right to move, has legal moves to play, and can force a draw, as you asked, but the draw is by stalemate:

[d]2kQ/3P/2KR/2RQ b

What am I missing?

Alex
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Ajedrecista
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Re: Minichess puzzle.

Post by Ajedrecista »

Hello:

You are probably missing nothing: the first move is a capture, as Kirill suggested, then black moves and white is stalemated, but white is not stalemated in the very first move.

It would be interesting to know how positions are counted because my definition differs from Kirill's.

Regards from Spain.

Ajedrecista.
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Kirill Kryukov
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Re: Minichess puzzle

Post by Kirill Kryukov »

Hi Alex,

Looks like you found it. Very nice!

"2kQ/3P/2KR/2RQ b" has legal moves, therefore it itself is not a stalemate. (I must be really bad at explaining things). :-)
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Kirill Kryukov
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Re: Minichess puzzle.

Post by Kirill Kryukov »

Ajedrecista wrote: Mon Mar 03, 2025 9:12 pmIt would be interesting to know how positions are counted because my definition differs from Kirill's.
Hi Ajedrecista, which definition are we talking about? My counting method is detailed in the NULP page ( https://kirill-kryukov.com/chess/nulp/ ), but please let me know if anything part there is unclear or hard to follow.
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Ajedrecista
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Re: Minichess puzzle.

Post by Ajedrecista »

Hello Kirill:

I was answering to Alex because he seemed to have doubts about stalemate: if we play a game from the position he found, it will end in stalemate after two plies (KxQ and white moves) and I think he thought it would count as a stalemate.

I thought the opposite because the first position is not a stalemate, regardless of how the game will end two plies later. I raised the doubt of how positions were counted because you did not see how such a position can be possible after an eventual KxQ... To be fair, your hypothesis was before Alex posted the position, so it was a 'blind guess' to call it in some way.

It looks like we (Kirill and me) agree after all! :-) I enjoy a lot these minichess puzzles and I always get the same outcome: close, but no cigar.

Regards from Spain.

Ajedrecista.
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Kirill Kryukov
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Re: Minichess puzzle.

Post by Kirill Kryukov »

Ajedrecista wrote: Tue Mar 04, 2025 6:23 amI enjoy a lot these minichess puzzles and I always get the same outcome: close, but no cigar.
Same, except I don't even get close. :)

Here is another puzzle.

In 4x4 chess, the kqqqqrrnkp ESM has 2,375,527 unique legal positions. Only two of them are checkmates (the rarest per ESM for up to 12 pieces). What are they? To be clear, the side with the 4 queens is checkmated. Also, the two positions must not be convertible to each other by any combination of symmetries or color swaps. Pawn is allowed on the first rank.
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Brunetti
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Re: Minichess puzzle.

Post by Brunetti »

Kirill Kryukov wrote: Wed Mar 05, 2025 3:28 am In 4x4 chess, the kqqqqrrnkp ESM has 2,375,527 unique legal positions. Only two of them are checkmates (the rarest per ESM for up to 12 pieces). What are they? To be clear, the side with the 4 queens is checkmated. Also, the two positions must not be convertible to each other by any combination of symmetries or color swaps. Pawn is allowed on the first rank.
One:

[d]2k1/2p1/RRNK/QQQQ

Alex
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Brunetti
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Re: Minichess puzzle.

Post by Brunetti »

Brunetti wrote: Wed Mar 05, 2025 9:04 am [d]2k1/2p1/RRNK/QQQQ
White to move of course, not Black.

Alex
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Brunetti
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Re: Minichess puzzle.

Post by Brunetti »

Brunetti wrote: Wed Mar 05, 2025 11:08 am [d]2k1/2p1/RRNK/QQQQ w
I can't find any other solution through logic.

Alex