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Betza notation (extended). The powerful XBetza extension to Betza's funny notation.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-12-03 UTC

I extended XBetza notation to give new meaning to the use of the z and q modifier in continuation legs of multi-leg moves, where the original meaning of crooked and circular are not useful. The intention was to solve the problem that in a bent trajectory that contains an s (also in combinations fs / bs) the equivalence of l and r is broken. A move described as afs...W starts like the Xiangqi Horse (W, and from there diagonally outward). But in a description like afsafrW the next bend in the path is 45 degree to the right, irrespective of whether whether the first bend was taken to the left or right. It thus describes two different move shapes (Alfil-like or Camel-like), rather than two orientations of moves of identical shape. That is incovenient: it preclude the use of s for compactifying the notation, and forces one to write the two symmetry-equivalent paths separately (afraflWaflafrW for the Camel-like or 'crooked' version).

From now on this can be written as afsafzW. The z then indicates that the path bends in the opposit direction as the preceding s. A sequence of z legs would thus always describe a crooked path. Similarly, a q would indicate bending in the same direction as the previous bend, and a sequence of q legs would give a circular path. This new use of the modifiers allows the description of the Falcon move to be shortened to afafsKafsafzfK: the first atom describes a path that bends after 2 steps, the second atom one that bends immediately, and then either bends in opposit direction (fz) or goes straight on (f).

Note that on oblique atoms the symmetry is broken from the very start, even without the use of an s. Such moves are interpreted as if they started in their longest direction. (So g1-f3 would be a 'left' move.) You should thus never use l or r in continuation legs of an oblique atom, or after an s leg, but always use z or q instead.


The Sultan's Game. Variant on 11 by 11 board from 19th century Germany. (11x11, Cells: 121) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-12-02 UTC

When castling, the king move four squares toward one of the rooks, and the rook jumps to the other side of the king.

That definitely sounds more sensible. I had to add a special parameter castlingGap to the Interactive Diagram to support the weird way of castling that is described in the text. (I see the Diagram in the article has already been changed to castle in the normal way, though, unlike the one I first published in the comments.)


Capablanca Random Chess. Randomized setup for Capablanca chess. (10x8, Cells: 80) [All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-12-02 UTC

Umm, I did not even know this rule existed. WinBoard restricts the shuffle only to have the Bishops on different colors. I agree the rule makes no sense. I have also seen descriptions that did not allow the Bishops to be on adjacent squares. (That also seemed to make little sense.)

The Interactive Diagram would have to struggle to enforce this rule, because there is no way to tell it directly that a pair of pieces of different types would have to be placed on different square shades. As a work-around you could 'mark' the shades by piece type, by defining the nominal start position with a back rank RBRBNKNCQA, so that RNQ are on dark squares, and BKCA on light. You can then order a sequence of shuffles, RNQ,BKCA,QA,!BNRKC .

The first shuffle solely serves to put Q on a random dark square, the second to put A on a random light square, and the third then randomly swaps the two. The remaining pieces then have to be shuffled the usual way, i.e. the Bishops would have to go on opposit shades (indicated by the ! prefix).

I guess it would be useful to extend the shuffling capabilities of the Diagram with a prefix to indicate the piece should stay on the same color as it was in the nominal setup. Sy This would be indicated by #, then the shuffle instructions could be K#QC#AR!BN,QA, with a nominal setup where Q and A start on different shades.


Interactive diagrams. Diagrams that interactively show piece moves.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-12-02 UTC

I finally got to upgrading the Diagram so that it would be able to support (a limited form of) double locust capture. In particular, I considered it a blemish that it was not able to handle the Lion Dog that occurs in the large Shogi variants (which can make up to 3 radial King steps per turn, and thus capture up to 3 pieces in one move). The AI of the Diagram was already capable of supporting any number of locust captures, but up to now it was not possible for the user to enter a capture with more than one locust victim (in addition to the normal victim in the destination square).

This is now fixed, albeit in a clumsy way. The Diagram still does not support locust capture of any pair of pieces, but only those where these victims are on the same ray, on the first and second square. But that is exactly what the Lion Dog needs. (This limitation came about by the fact that it still uses only a single e.p. square, which then implies the second square.)

There was a lot involved in getting this to work. (It needed new code for generating the move notation, parsing such moves when you paste a game, communicating it to and from the AI, and of course for interpreting the clicks made when you enter a move.) I hope that I got everything right. I also made the Diagram smarter in understanding XBetza descriptors that have both destructive and non-destructive action at the square connecting the legs. (These need a different set of clicks to play: non-destructive intermediates, like the corners in a bent-leaper trajectory, never need to be clicked, while locust victims do.)

The Lion Dog can now be represented in XBetza notation as: KADGHcavKmcafcavKpafcafKcafmpafK . This is a bit cumbersome, but I saw no easy way to allow a 2-out-1-in move (using v in the 3rd leg) only when the first square gets captured or already was empty, and forbid it (using f)when it was an occupied square that was hopped over. So 3 types of three-leg moves need to be described. I guess to also describe null move an extra abK would be needed.

[Edit] I guess that the slightly more compact KADGHcavKmpafcavKcafcmpafK would also work. This only needs two descriptions of the 3-leg move. One for the 3-out move that captures the adjacent victim, and in addition optionally the one on the second square. And another that in any case captures two squares away, and then either continues either out or in. Possibly making a normal capture on its destination. The disadvantage of this is that for the 2-out-1-in move the victims are captured in reverse order (furthest first). Which could make a difference in the case of contageon, when both the captured pieces are contageous. (As they could be in Maka Dai Dai Shogi. Although this is of course a 'never happens' situation.)


The Sultan's Game. Variant on 11 by 11 board from 19th century Germany. (11x11, Cells: 121) [All Comments] [Add Comment or Rating]
Jean-Louis Cazaux wrote on 2021-12-02 UTC

The rule of castling is not correct as far as the Rook is concerned. When castling, the king move four squares toward one of the rooks, and the rook jumps to the other side of the king.

This will be corrected in future editions of A World of Chess, by JL.Cazaux and R.Knowlton.

In addition, the name Tressan has to be corrected to Tressau on this page.


The Emperor's Game. Variant on 10 by 10 board from 19th century Germany. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Jean-Louis Cazaux wrote on 2021-12-02 UTC

The rule of castling is not correct as far as the Rook is concerned. When castling, the king moves three squares when castling short and four when castling long. The rook jumps to the immediate square on the other side of the king.

This will be corrected in future editions of A World of Chess, by JL.Cazaux and R.Knowlton.


Capablanca Random Chess. Randomized setup for Capablanca chess. (10x8, Cells: 80) [All Comments] [Add Comment or Rating]
Thomas wrote on 2021-12-02 UTCExcellent ★★★★★

But why the limitation to set up queen and archbishop on different coloured squares, when they can change the square colour by moving like rook resp. knight?


Home page of The Chess Variant Pages. Missing description[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-12-02 UTC

The re-definition of the piece images is at the bottom of the Pre-Game section in all these presets. Somewhat further down in this discussion Aurelian posted a link to an ongoing game with this preset, where the problem manifests itself.


Aurelian Florea wrote on 2021-12-02 UTC

@Fergus, Thanks for taking the time!

In the following preset:

https://www.chessvariants.com/play/pbm/play.php?game=Grand+Apothecary+Chess+1&settings=Applet

the pictures are not shown properly.when playing in online mode. In the local play mode things are fine.

In two other very similar presets:

https://www.chessvariants.com/play/pbm/play.php?game=Grand+Apothecary+Chess+2&settings=Applet https://www.chessvariants.com/play/pbm/play.php?game=Grand+Apothecary+Chess+3&settings=Applet

things work properly. Nor I or HG could figure it out. Maybe you can! I don't know how to reproduce it besides looking at the proper preset.


Fergus Duniho wrote on 2021-12-02 UTC

I have been busy with other things. What is the specific issue you are having, and how can I duplicate it?


Symmetric Chess. Missing description (9x8, Cells: 72) [All Comments] [Add Comment or Rating]
Carlos Cetina wrote on 2021-12-02 UTC

Very good, having cleared the cache and deleted the cookies, the AI no longer commits the illegality of not converting the bishop. Now it plays 24 ... Qc4. Continuing the game it developed like this:

1.g3 d5 2.d4 f5 3.Bg2 e6 4.f4 Qb4 5.c3 Qb5 6.Nf2 g6 7.Nd3 a5 8.a4 Qc4 9.Nd2 Qc6 10.Ne5 Qb6 11.b3 Nc6 12.Ndf3 Qd6 13.Ba3 Qd8 14.Bc5 Qa6 15.Qf2 Nxe5 16.Nxe5 b6 17.Ba3 Nf7 18.Nxf7 Bxf7 19.O-O Qf6 20.c4 dxc4 21.Bxa8 Qxa8 22.Ki1 cxb3 23.Rb1 Qd5 24.Rxb3 Qc4 25.Rd3 b5 26.axb5 Qxb5 27.Qa1 i5 28.Rb1 Qd5 29.Bc5 Qa8 30.Qa4 c6 31.Bb6 Bd8 32.Bxd8 Kxd8 33.Rdb3 Qa6 34.Rb6 Qa7 35.Qxc6 h5 36.Qd6 Qd7 37.Rb8#

Thanks for showing me the solution. So when will we see the Interactive Diagram offered on the Google Apps Store?


H. G. Muller wrote on 2021-12-01 UTC

When I paste that game up to move 24 back into the Diagram, and then play Rxb3, it doesn't reply with that same Bishop move. And when I play the (illegal) move Qa6 instead of Rxb3 it doesn't capture the Queen, but plays Bd8. Did you flush the browser cache, (Shift + reload in FireFox) to make sure you are using the latest version of the diagram script? You might have been using the old version where I hadn't implemented the rule yet. If you are sure you have flushed the cache you can paste the moves 1-23 back in the Diagram (in the dashed text box below the navigation buttons), and continue the game from there.


Carlos Cetina wrote on 2021-12-01 UTC

It seems that there is a bug such that the AI does not always make the conversion as can be seen in the following game on move 24 of the blue side:

1.g3 d5 2.d4 f5 3.Bg2 e6 4.f4 Qb4 5.c3 Qb5 6.Nf2 g6 7.Nd3 a5 8.a4 Qc4 9.Nd2 Qc6 10.Ne5 Qb6 11.b3 Nc6 12.Ndf3 Qd6 13.Ba3 Qd8 14.Bc5 Qa6 15.Qf2 Nxe5 16.Nxe5 b6 17.Ba3 Nf7 18.Nxf7 Bxf7 19.O-O Qf6 20.c4 dxc4 21.Bxa8 Qxa8 22.Ki1 cxb3 23.Rb1 Qd5 24.Rxb3 Bd7 25.Rc3 c5 26.Rd3 c4 27.Rd2 i5 etc


Carlos Cetina wrote on 2021-12-01 UTC

Magnificent! I encourage you to publish your Interactive Diagram in the aforementioned apps store since it is a very good showcase to spread ideas, in such a way that a certain number of variants could be played by default (including Symmetric Chess, of course!). I believe that you could get a fair remuneration in money for your work including banner ads. Using the app would be free. What do you say?


H. G. Muller wrote on 2021-12-01 UTC

Do you think that the Interactive Diagram software could be used in the Android environment?

I know that for sure. It is browser-based, and every OS nowadays has a browser that understands HTML and JavaScript. So you don't need a separate App for it. (Of course the browser is also an App, but I assume everyone already has that.) It works fine on my Samsung Tablet.


Carlos Cetina wrote on 2021-12-01 UTC

Thank you very much, HG. It's a great improvement.

One of my biggest dreams is to see one day in the Google Apps Store one with which this chess variant can be played against the AI. Do you think that the Interactive Diagram software could be used in the Android environment?


H. G. Muller wrote on 2021-12-01 UTC

I have implemented the bishop conversion rule now as a standard feature of the Interactive Diagram. So that it is now also possible to play Symmetric Chess against the AI (for which the trick of changing both bishop's piece types when one of them moved did not work). All that is now required is define the bishop with an extra initial iW move, and add a parameter conversion=N, where N is the number of the piece table of the piece to which the rule applies. (So here N=3). The first moves of pieces of this type are then forced to go to different square shades.

files=9 promoChoice=NBRQ graphicsDir=../graphics.dir/alfaeriePNG/ whitePrefix=w blackPrefix=b graphicsType=png squareSize=50 symmetry=none conversion=3 pawn::::a2,b2,c2,d2,e2,f2,g2,h2,i2,,a7,b7,c7,d7,e7,f7,g7,h7,i7 knight:N:::b1,h1,,b8,h8 bishop::BiW::c1,g1,,c8,g8 rook::::a1,i1,,a8,i8 queen::::d1,f1,,d8,f8 king::::e1,,e8

Home page of The Chess Variant Pages. Missing description[All Comments] [Add Comment or Rating]
Aurelian Florea wrote on 2021-11-30 UTC

Fergus, Are you here?


Play-test applet for chess variants. Applet you can play your own variant against.[All Comments] [Add Comment or Rating]
H. G. Muller wrote on 2021-11-29 UTC

How to remove a piece from the diagram. For example if I want to put the King on another square than those on which they stand by default?

You can move the pieces over the board, just like you can when you use the diagram for playing. If you want to remove a piece that you selected by mistake, but do not want on the board after all, it is a bit more tricky: you would have to capture it with another piece, and the Diagram only accept attempts to capture if they are pseudo-legal moves (i.e. when the piece to capture gets highlighted when you select the piece you are going to capture it with.) Best way is just to move the piece next to the opposing king (moves to empty squares are always accepted, even when not pseudo-legal), and then capture it with the king, and finally move the king back to where it belongs.

Also, how to use "paste an existing diagram". For example, I want to create a play-test for Shako. What can I paste in that box, an image? the link for the shako page? something else? I don't know how to use this?

That box is for pasting diagram descriptions of the type you get when you press the 'Show HTML' button at the bottom of the article. It is intended for trying out diagrams that you modified by editing the text of their description, e.g. to implement some features that the Play-Test applet would not allow you to switch on. Such as Shogi-style promotion. You can then first make the Diagram without that feature, ask for the HTML, paste it in a text editor to modify it, and copy-paste the modified version back into the diagram. Or when you get a Diagram from another page (by asking for 'Page Source', and copy-paste from there. (I discovered that also there you have to paste it into a text editor first; directly copying from the Page Source seems to leave in all kind of invisible formatting information the Play-Test Applet chokes on.)

E.g. when you want two promoting piece types, you would have to add the line maxPromote=2 to the Diagram description, otherwise only Pawns will promote.

[Edit] I forgot to say: there is also a button for creating GAME code for automating a Game Courier preset. Originally the paste box was added to make it possible to convert an Interactive Diagram that you made before and posted somewhere else to GAME code. Without the need to entirely recreate the Diagram through the Applet. Which for large variants would be more cumbersomet than just copy-pasting an existing and well-tested Diagram into the box, and pressing the GAME-code button.


Jean-Louis Cazaux wrote on 2021-11-29 UTC

How to remove a piece from the diagram. For example if I want to put the King on another square than those on which they stand by default?

Also, how to use "paste an existing diagram". For example, I want to create a play-test for Shako. What can I paste in that box, an image? the link for the shako page? something else? I don't know how to use this?

Thank you


Advanced Hexagonal Chess. Hexagonal variant that has no equal.[All Comments] [Add Comment or Rating]
Max Koval wrote on 2021-11-29 UTC

It is ready to be published.


Pandemonium (Surajang修羅場). Capablanca chess + Crazyhouse.[All Comments] [Add Comment or Rating]
Daphne Snowmoon wrote on 2021-11-29 UTC

Piece list added !


Play-test applet for chess variants. Applet you can play your own variant against.[All Comments] [Add Comment or Rating]
Daniel Zacharias wrote on 2021-11-29 UTC

Thank you, I got it working


Chess with Different Queens. players choose their super pieces.[All Comments] [Add Comment or Rating]
B.E. Dolata wrote on 2021-11-28 UTC

H.G. Muller, thanks for the comments. I've also been doing some testing in ChessV.

White: Queen, Black: Queen
White wins: 94
Black wins: 93
Draws: 113
White: Griffon, Black:
White wins: 177
Black wins: 48
Draws: 75

I'm currently running test on the Archbishop and Chancellor.

The Queen-Griffon was matchup is fairly lopsided in the simulations, but its close enough that that I still found it fun to play myself. I haven't tested the Griffon-Lion matchup yet either in the computer or over the board, but your results for the KaFafsW Lion make me think that it could be unplayable. I will run some tests with the Q2afsW after my current games finish running and see if this tones down the Lion sufficiently.


H. G. Muller wrote on 2021-11-28 UTC

I see that the Lion now has become a regular 2-step area mover. I tested a Lion that was blocked more easily (KaFafsW), because it was missing the Moa path and lame Dabbabah (nD), so that only the D move was multi-path (reachable in 2 ways), by pitting it against a Queen in Fairy-Max. To my surprise the lameness did not weaken it that much compared to a KNAD: it beat the Queen by 63% in 200 games, which is only slightly smaller than the Pawn-odds score.

The balance could still be improved a little by making every square on the 'second ring' reachable through a single path only. E.g. the A squares through the F squares, (as they already are), and all others through the W squares. So that it becomes a compound of a range-two Queen and a Xiangqi Horse (Q2afsW). That would most likely still leave it stronger than a Queen, while all other replacements are weaker than Queen.

I also tried the WyasW against a normal Griffon. It was only marginally stronger. I guess it suffers a lot from the fact that the paths cross on the F squares, which means that there now are 8 squares where two of its arms can be blocked. This makes the detour over the W squares nearly as much as a liability as an asset. Furthermore, it made the piece very difficult to develop; the initial F step is really useful for sneaking between Pawns. This was quite annoying, so I would not recommend use of this piece. and stick to the regular Griffon.


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