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Devingt Chess. Decimal chess with 20 pieces per side including Sages (moving as Camels).[All Comments] [Add Comment or Rating]
Fergus Duniho wrote on 2022-04-16 UTC

Her game was already produced in the 90s, and if people don't know how to play it, they won't be playing it. Anyway, if these games happen to be identical, it looks like the Devingt Chess inventor will get the credit for the game, and the Cardinal Super Chess inventor will not. My experience, though, is that people who independently make similar games usually don't make identical games.

Jean-Louis Cazaux wrote on 2022-04-16 UTC

I have contacted the creator of Cardinal Super Chess to know the details of her rules (castling, initial P's move, promotion). She replied "My board and innovations are copywritten. I am not revealing all my rules as yet, until I produce it. I have some special rules. I know you understand". To be frank, no, I don't understand the need to hide rules of a chess variant. But I respect that choice. Whatever, I think I have my answer, it is very unlikely that Devingt Chess has been copying Cardinal SC, as I was suspecting knowing its author, quite poorly informed about chess variants.

Jean-Louis Cazaux wrote on 2022-04-15 UTC

Wonderful. It seems to work perfectly fine. Thank you

Fergus Duniho wrote on 2022-04-15 UTC

I think I fixed that now. Try it again.

Jean-Louis Cazaux wrote on 2022-04-14 UTC

Yes I agree. Thanks for coding the GC for Devingt Chess. But according to the tests I've made, the Pawn's promotion doesn't work. I get a rectangle with ? when the Pawn reaches the last row.

Fergus Duniho wrote on 2022-04-14 UTC

Yes, certain ideas seem to reoccur more often to people thinking up new Chess variants. It's good to keep a public record of them so that people don't keep reinventing the same game. For example, several people separately reinvented Spherical Chess, and some versions differ from others by only a single rule.

Jean-Louis Cazaux wrote on 2022-04-14 UTC

I added a note to mention the similarity with Cardinal Super Chess. At this moment I don't know what were the details rules. The inventor of Devingt Chess was ignorant of Cardinal Super Chess nor the other similar variants. It seems that this game or a similar one is, like chess for 3 players, chess for 4 players, chess on hex, a chess variant which is "invented" often and rather regularly. This one is not the first and probably not the last one on 10x10 boards with Camels.

Fergus Duniho wrote on 2022-04-13 UTC

I don't have a set myself. David and Hans each had one, and Hans programmed a Java applet to play it that appeared on the website for the game.

Jean-Louis Cazaux wrote on 2022-04-13 UTC

Do you have more information on Cardinal Super Chess. I mean more than what is in Pritchard's? I wonder what are the rules for Pawn's initial move, castling and Pawn's promotion. These were probably described in the game leaflet but I don't have it.

Jean-Louis Cazaux wrote on 2022-04-13 UTC

It's my fault. The incriminated photos are wrong. I had to remove them but I forgot. I do it now. Thank you.

For the connection with Cardinal Super Chess I have to investigate.

Fergus Duniho wrote on 2022-04-13 UTC

I've noticed some differences between the photos and the diagram. In both the photos, a1 is a light square, but in the photos, it is a dark square. Additionally, the two photos do not have the same setup as each other, and neither one matches the diagram. The first one superficially appears to match the diagram, but it is from Black's perspective. That means the King is actually on the f file, and the Queen is actually on the e file. In the second photo, White's King and Queen have swapped places, giving the game rotational symmetry instead of mirror symmetry.

Fergus Duniho wrote on 2022-04-12 UTC

Is this the same game as Cardinal Super Chess? This was also a commercial game that used the same board, the same pieces, and the same setup.

Jean-Louis Cazaux wrote on 2022-04-07 UTC

HG, I smile. "Pourquoi faire simple quand c'est si simple de faire compliqué ?", as we say here, could be the answer to your statement. :=) I try to focus a bit on my project to make it progress. But soon or later I will have to try your applet, I'm curious anyhow to see how it works. Promise, I will. Thanks to all.

H. G. Muller wrote on 2022-04-06 UTC

Well, if doing it the hard way turns out to be too hard, it might not be such a crazy idea after all to do it the easy way instead.

Fergus Duniho wrote on 2022-04-06 UTC

I know what it's like to have other things to do. That's the story of my life. The best way to learn may be by example, using the tutorial only to explain things further. With that in mind, I have updated the Grand Chess preset with better organization and helpful comments to let you know what the code is for. Since there is no castling in Grand Chess, it won't help you with that, but it will help you get down some of the basics for creating a preset that uses the fairychess include file.

Jean-Louis Cazaux wrote on 2022-04-05 UTC

OK thanks. At last I understand. I'm not an IS expert, I can't get into all this. Too much things to learn, after 10 lines of reading of these long pages of tutorials, I'm lost. Every change I made is to understand that I have to change something else and I don't know where this will drive me. I give up, I can't spend more time on this, I am busy with other projects. Going back to my first demand, I prefer that this preset remains not accessible as it is an unfinished work.

Fergus Duniho wrote on 2022-04-05 UTC

The fairychess include file is not a drop-in replacement for chess2. It introduces new paradigms on how to program a preset. One major difference is in the names of functions and subroutines. Instead of naming them after piece labels, they are now named after piece codenames. The tutorial gives details on this. I would recommend starting with a preset that already works with the fairychess include file and adapting it to work with your game.

Jean-Louis Cazaux wrote on 2022-04-05 UTC

Thanks I'm learning little by little. So much knowledge to absorb.

I have switched chess2 to fairychess but now I can't play at all.

I get:

Syntax Error on line 722

The function '' has not been defined. Its arguments are a10 e1

Line 722 is:

722 if fn const alias #piece #from var king

I don't understand what's wrong

Fergus Duniho wrote on 2022-04-04 UTC

Gross chess works fine for that. I can't see where is what I miss for Devingt.

You are using the chess2 include file instead of the fairychess include file. You should switch to the fairychess include file, because it is more up-to-date, and the new subroutines I mentioned to you are in that include file. To learn about what makes it different, you should check out the tutorial on the fairychess include file.

Jean-Louis Cazaux wrote on 2022-04-04 UTC

Thank you for your help.

For en-passant, I had put already fps to 3. The pawn can advance 1, 2, 3 yes but the problem is en-passant. A pawn on 6 can take ep a pawn which advance 3 sq. Good. A pawn on 7 can take ep a pawn which advance 2 sq. Good. But a pawn on 7 cannot take ep a pawn which advance 3 sq.

Gross chess works fine for that. I can't see where is what I miss for Devingt.

Fergus Duniho wrote on 2022-04-03 UTC

en-passant: a pawn on 7 should be able to take en-passant an opposed pawn that had moved 3 sq.

This is handled in the preset for Gross Chess. The Pawn functions and subroutines in the fairychess include file should handle it automatically if you set fps to 3.

promotion: only for captured pieces, a pawn on 9 cannot step on 10 if no piece is available.

The preset for Eurasian Chess can handle this. In the Pre-Move sections, it sets a value for wprom or bprom that is based on the currently captured pieces. Each variable should be set to the pieces that a Pawn may promote to. These variables are static for Chess but dynamic for Eurasian Chess. When it is empty, a Pawn may not move to the last rank. Here's what it looks like for Pre-Move 1 for White:

set wprom intersection keys capturedpieces array Q R B N C V;

Fergus Duniho wrote on 2022-04-03 UTC

castling: the K may move 2 OR 3 sq towards the R

I just added some subroutines to the fairychess include file for this. These are castle2, castlepos2, and stalemated2, which are substitutes for castle, castlepos, and stalemated. Unlike castle and castlepos, castle2 and castlepos2 take four arguments instead of two. The first two are the same as before, the from and to coordinates for the King. These should be followed by the from and to coordinates for the piece the King is castling with. Unlike castle, which will handle all possible castling moves in the direction of the King's move, castle2 specifies a specific castling move. The stalemated2 subroutine differs from stalemated by calling castlepos2 and by writing out legal castling moves as two-piece moves.

The code in the preset also has to be changed to accommodate this. This line should be added in the Pre-Game code:

allow moves 2

You will also have to set different values for bcastle and wcastle. Instead of giving them a list of all the spaces a King may castle to, each should be given a list of fully described castling moves. Each should appear as four coordinates in parentheses in the same order they are fed into castle2. For your game, you would want to include four sets of coordinates for each King, one for each specific castling move.

In the Post-Move sections, castling moves have to be handled separately from regular moves. This means that the King subroutine should be rewritten to not include castling. An example of what to do can be seen in the preset for Miller's Spherical Chess, which uses the versions of these subroutines from the logical include file. The relevant code looks like this for White:

if isupper alias $prevmoved:
  if == $prevmoved K and == $moved R:
    if == $origin a1:
      gosub castle2 e1 c1 a1 d1;
    elseif == $origin h1:
      gosub castle2 e1 g1 h1 f1;
      die $moves "is illegal. Go back and try again.";
  elseif != $prevmoved P or != $moved P or != $prevdest $dest:
    die "Except for castling or pawn promotion, you may not move twice on the same turn.";
elseif ...

This uses the variable $prevmoved for the previous value of $moved. Usually, $prevmoved will have the piece last moved by the opponent. This block of code will run if the piece in $prevmoved belongs to the player moving, which happens in a two-part move. In Chess, these would be castling or pawn promotion. In a castling move, $prevmoved will have the player's own King. Using this variable saved me from having to write code like I did for multi-move variants. If it's not a castling move, it returns an error unless it is a pawn promotion. This lets the code exclude other double moves. Note that this code would have to be tweaked for your game.

Finally, the Post-Game code should use stalemated2 instead of stalemated.

H. G. Muller wrote on 2022-04-03 UTC

The Play-Test Applet would have no problems to generate GAME code that handles the castling and the e.p. capture as desired, when the King's move is defined as KisO2isO3, and the Pawn's move as fmWfceFifmnDifmnH. The promote-to-captured can be requested by prefixing the pieces in the promoChoice string with a *. I am not completely sure whether it would then suppress the highlighting of a Pawn step to last rank if there is nothing to promote too, but in any case it would not accept such a move if the user selected it as destination.

Jean-Louis Cazaux wrote on 2022-04-03 UTC

The page for Devingt Chess is OK.

But the preset GC for Devingt Chess is not OK. It should not be published as this. It is an unfinished work because I don't know how to code several rules:

  • castling: the K may move 2 OR 3 sq towards the R

  • en-passant: a pawn on 7 should be able to take en-passant an opposed pawn that had moved 3 sq.

  • promotion: only for captured pieces, a pawn on 9 cannot step on 10 if no piece is available.

Jean-Louis Cazaux wrote on 2021-09-23 UTC

Could it be possible to release this page now? Thanks

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