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Piece Values on 8x10 Board[Subject Thread] [Add Response]
Kevin Pacey wrote on 2018-12-31 UTC

James Zuercher wrote on 2018-12-09 EST

Have the piece values on an 8x10 board been determined for the following variant pieces? Dragon Horse, Dragon King, Crowned Rook, or Gnu. If so what are these values and how were they determined?

In the better late than never spirit, now that there's a bit of a lull, I'll give you my own roughly estimated values calculated just now for such pieces, and how I reached them (noting first that a Crowned Rook is another name for a Dragon King, as is noted in CVP's Piececlopedia):

Dragon Horse (Bishop+Wazir compound piece) I estimate as =B+Wazir+P,

where largely based on the average number of squares a B can reach I guess [single] B roughly=3.75 (note I rate B=3.5 on 8x8, and prefer a B always worth less than 4 pawns),

Wazir = (Guard-P)/2 (note Guard=Ferz+Wazir compound, which I rate as =Ferz+Wazir+P, with Ferz approx.=Wazir); Guard's value on 8x10 computed by my home formula of 32x(max. number squares guard reaches)/(number of cells on board)=32x8/80=3.2 in this case (note this home formula doesn't seem to work too badly for a large range of board sizes, but there are limits). Thus Wazir=(3.2-1)/2=1.1 on 8x10.

Thus Dragon Horse on 8x10= 3.75+1.1+1=5.85 is my estimated value.

For Dragon King (Rook+Ferz compound piece) it's rated by me =R+Ferz+P where I estimate R=5.5 (unchanged from what I give it as on 8x8).

Thus Dragon King on 8x10= 5.5+1.1+1=7.6 is my estimated value.

For Gnu (Knight+Camel compound piece) it's rated by me =N+C+P where Camel is still assumed by me=2 on 8x10 (like it is commonly given by other people, and myself, as for camel on 8x8). I rate a Knight =3.5 on 8x8, but for board sizes other than that I'd apply a home formula which is rather complex, and doesn't work for every possible board size (similar to my Guard formula given earlier). If I've got it written down right, I estimated N=3.5-(0.25x{[no. rows]-8}/2+0.25x{[no. columns]-8}/2)+(Average number of squares N can move to on empty board-5)/8 for a given board size. For 8x10, I've thus worked out an estimated value of 3.38 for a N. Note that, like for the case of a B, on 8x10 a N has a considerable number of juicy squares in terms of influence, if it reaches any of them (which in the case of a N helps compensate somewhat for the greater board size than 8x8, IMHO).

Thus Gnu on 8x10=3.38+2+1=6.38 is my estimated value.


Checkmating Applet[Subject Thread] [Add Response]
Ben Reiniger wrote on 2018-12-24 UTC

Re: earlier points, see the applet's page.

On the other note:

While doing this it turned out the form for editing a submission has a pretty bad bug: in the first draft I had forgotten to adapt some links, and it included a header that turned out redundant. But when I try to edit, the edit window initializes each time with the first version I submitted, reverting all the changes I made in previous edit sessions, I then have to redo all these, and not forget a single one, or I would be back to square a1...

I played around with this for a little bit, and I think it's your browser caching the old submission data.  Refreshing the page fixed the problem for me.  (We could add a dummy variable to the end of the url as Fergus did for the Random Game menu link, but that might cause worse issues for using the browser's back button when submission fails e.g. because of being logged out?)


H. G. Muller wrote on 2018-12-23 UTC

Indeed, that is a very useful feature!

I now uploaded the EGT.html to the Interactive Diagrams membergraphics folder. It can be linked to from the Piececlopedia pages, with the arguments to specify the move, name and symbol for the piece in question through the parameters 'betza', 'name' and 'img' (where the latter should be the root Alfaerie name, i.e. without the w/b prefix and extension). I guess we would want to do this both for pieces with general mating potential, and pieces that can only force mate in exceptional cases, but perhaps through different remarks. E.g.

  • This piece can almost always force checkmate on a bare king. Try it!
  • This piece can only force checkmate on a bare king from some very favorable positions. Try it!
  • It is not possible to deliver checkmate with just this piece and a King.

I also submitted an article, called 'Checkmating Applet', with the more general version of the applet that I had on my website. This includes the interface for defining piece moves. (I left out the button for some specific (mainly Musketeer Chess) pieces.)

While doing this it turned out the form for editing a submission has a pretty bad bug: in the first draft I had forgotten to adapt some links, and it included a header that turned out redundant. But when I try to edit, the edit window initializes each time with the first version I submitted, reverting all the changes I made in previous edit sessions, I then have to redo all these, and not forget a single one, or I would be back to square a1...


Greg Strong wrote on 2018-12-23 UTC

(And, a little hack for more flexible formatting: if the Introduction section is the only non-empty one in a member submission, the header is suppressed, and you can use your own html headers directly.)

Oh wow, I didn't know that!  Thanks :)


Ben Reiniger wrote on 2018-12-23 UTC

That was my understanding of how Fergus reworked the upload script.  I've put such a placeholder file there, so we'll see soon whether that's right.

I could see the checkmating applet fitting in its own page.  If nothing else, that'd be a little more convenient for linking to, and would give it its own index entry for comments.

(And, a little hack for more flexible formatting: if the Introduction section is the only non-empty one in a member submission, the header is suppressed, and you can use your own html headers directly.)


[Subject Thread] [Add Response]
Aurelian Florea wrote on 2018-12-23 UTC
Thanks HG!

Checkmating Applet[Subject Thread] [Add Response]
H. G. Muller wrote on 2018-12-23 UTC

In WinBoard I use the Unicorn image as the Royal Knight in Knightmate, so I was probably thinking of that. The Camel-Zebra compound is usually referred to as Bison, but the lame multi-path version of it is George Duke's Falcon, and in WinBoard I use the letter V for the Falcon symbol. (Because F was already taken by Ferz, and Dutch for Falcon is 'Valk'.) Not sure why I gave S the same move. Anyway, the main idea of the piecedef.ini file was that people could put their own piece definitions in there.

Note that the basic version of the generator assumes total symmetry and an 8x8 board. If you undefine the symbol DIAGSYM in the source code and recompile it would only assume 4-fold symmetry. This is not only needed for doing less symmetric pieces, but also for non-square boards. The way diagonal symmetry is implemented is leaning very much on the board size being 8x8, because it extracts the X and Y coordinates of the pieces by masking out groups of 3 bits from the index (through the RANKS and FILES masks) to be able to swap those. Even without diagonal symmetry it would not be so easy to adapt to other board sized; e.g. the tables bcode[] and deltaVec[] assume '0x88' square numbering, and would have to be changed.

FairyGen doesn't use any bitboard techniques, so the fact that the word length of a computer is only 64 bits in principle should not pose any limitation. It is just that everything having to do with square numbering and index calculation would have to be changed.


Aurelian Florea wrote on 2018-12-23 UTC

@HG

By the way in the definition of the default file as it is downloaded you are trying to define an U (probably an unicorn or nightrider) but you are just putting down another knight. An extra "s" is required maybe. That is for future not carefull users. Also for the V and S pieces you defined an camel zebra compound twice. No ideea what is all that about :)!


Aurelian Florea wrote on 2018-12-23 UTC

Thanks!

The actual thing I'd like to use if for is to test the 5 man endgames for my 2 apothecaries games.

That is beyound the scope of the program as the 2 apothecary games are 10x10 and even worse it uses the joker (fool, imitator) which is not being defined in FairyGen.

But there seems to be enough information for me to build the program myself for a more general purpose. The main dificulty is probably the board representation as an 64 structure bits is not usefull any more. The joker implementation should be more staightforward but there maybe have to be some recurrence there too. I still have not though about it :)!


H. G. Muller wrote on 2018-12-23 UTC

@Aurelian:

FairyGen can be downloaded from http://hgm.nubati.net/fairygen.zip . The archive contains a README.txt with an extensive description for how to use it.

@Ben:

This is a nice idea. But I think the initial posting would still need editor assistance to upload it as an attachment, as *.html is not one of the allowed file types in the upload script. Fergus made some special provision in that script which allowed me to update the /membergraphics/MSinteractive-diagrams/betza.js file, and I hope this works by allowing the use of any filename that already exists, so that it would also work for an already-present .html file. (I have no way to test that, though.)

So perhaps you should just put a (dummy) file /membergraphics/MSinteractive-diagrams/EGT.html on the server, so I can update it to the real version, and later edit it when necessary. I don't think there is any need to create a separate member-submitted article just for the purpose of hosting the EGT.html attachment; I would not really know what to write in there, and the article format enforced on member submissions is not very suitable for anything other than chess-variant descriptions anyway.


Ben Reiniger wrote on 2018-12-23 UTC

Would it be better to work in as something you can edit directly later?  IIRC, the way your interactive diagrams are hosted through a post-your-own-page attachment?  I think we can reindex correctly; I'll look into that later, but want to throw the idea out now in case you see another problem with it.


Aurelian Florea wrote on 2018-12-22 UTC

@HG

What I had found is something else!

So back to square one! Silly me!


Aurelian Florea wrote on 2018-12-22 UTC

@HG!

I had found it by google, in the end, here:

http://home.hccnet.nl/h.g.muller/EGTB.html

So I guess that settles it.

Thanks, HG!


Aurelian Florea wrote on 2018-12-22 UTC

HG,

Hello!

Earlier on this post you had mentioned Fairy Gen.

I have a few questions:

1. Where  can I find it?

2. Is it yours? Who has authored it?

3. Is it open source? Can I see the code?


H. G. Muller wrote on 2018-12-22 UTC

It appears that the JavaScript version of the EGT generator has too much 8x8 logic hard-coded into it that for now I cannot easily change it to also do other board sizes. I posted a version of the page on my website that only prints a summary of the statistics, and can accept arguments w.r.t. the image, move and name of the piece as 'get' arguments to the URL. Like:

http://hgm.nubati.net/rules/EGT_CVP.html?name=archbishop&betza=BN&img=cardinal

It already links to images and the diagram JavaScript present on the CVP website (I used Alfaerie .gif images), but from my own website this of course had to be done through "off-site" links of the type "http://www.chessvariant.com..."; when it would be on the CVP site the initial site address could be omitted from those links.

Perhaps a CVP editor can copy the page to the CVP website (and possibly dress it up with CVP logos). Apart from the link to the diagram's betza.js script in <script> tags and to the directory with piece images as graphicsDir in the diagram's description, and a link to the directory with marker symbols for the diagram at the end, the page is 'self-contained'. (I.e. the JavaScript for building the EGT and probing it during play is inside the page.)

Beware that the EGT generator currently can only do regular sliders and leapers, and that it would be blind to more advanced modifiers supported by the diagram, such as divergence, multi-leg moving or hopping. Pure hoppers would not have mating potential with only their King as support, though, and most other pieces in the Piececlopedia are regular slider/leaper compounds, so this doesn't seem much of a problem. (Bent sliders are a problem, though, so the Gryphon cannot be handled yet.)


H. G. Muller wrote on 2018-12-20 UTC

The calculation is entirely done client side, so that is no problem. I will try to prepare a version that takes the Betza description of the piece from the URL. (And perhaps the name of the image to be used for this piece as well.) And it will just print a statistics summary rather than the entire DTM table. I will also omit the interface for letting the user design its own pieces.


Greg Strong wrote on 2018-12-19 UTC

I like the approach being described.  The endgame-generator is awesome and we should certainly make it available here, so long as the actual computation is done client-side.  (Our hosting provider terminates the entire server when our CPU quota is exceeded.)


Ben Reiniger wrote on 2018-12-19 UTC

That's all pretty much how I was thinking of how to implement it too.  Since the Piececlopedia is fairly small, I'm inclined to just edit by hand.

I've been wanting to database-ify some Piece information; maybe linking to the applet page with piece Betza notation, drawn from such a table, would be a good starting point.


Almost Grand, a very modest variant[Subject Thread] [Add Response]
Joe Joyce wrote on 2018-12-18 UTC

Hi, HG! Thanks for the reply. Grin, I agree Grand Chess et al is a very immodest variant. But then Christian is the Ralph Betza of abstracts. He is the one who makes the distinction between variants of chess and variant chesses. And if FIDE wasn't so firmly enshrined in the psyche of the West, that would be a distinction with very little to no meaning. But as it is, make one little change, you are a heretic, and your audience size goes down at least 5 orders of magnitude.

I looked at Elven, and read some of the comments. If you don't mind my saying so, I think it would make a nice partner to Hannibal in a site tournament. It has that power that most here like, and has the kicker of the Chu Shogi Lion, a moderately terrifying piece which is rather unknown here, isn't it? Hmm, if I were to introduce that piece, I'd start by pairing it with my Lemurian hero and shaman, and Greg has a piece (griffin?) that has a similar movement to the hero... heh, one of the problems I have in discussing chess variants is that it gets me thinking of variant designs. Anyway, apparently I can claim Almost Grand as a very modest variant of Grand Chess, and even make a play for Almost Capa. And with that last, I can make the claim I seem to be pretty good at finding the obvious. ;D

Merry Christmas, all, and I hope your Chanukah was happy!

 




Checkmating Applet[Subject Thread] [Add Response]
H. G. Muller wrote on 2018-12-18 UTC

I agree that the whole table hardly contains relevant information. (The reason I had the applet displaying it was mostly for debugging, to compare with the known statistics of orthodox pieces.) It would be sufficient to just print percentages won and drawn, and the average and maximum number of moves needed to force mate in a won position. It would of course be easy to suppress the more detailed info.

The applet is inherently dynamic, and only calculates information for the board size seen in the accompanying diagram where when can practice the end-game. The time needed to calculate the End-Game Table for an 8x8 board is pretty short, but it rises quickly with board size (as the cube of the number of board squares), so that doing many different board sizes (some large) at once would be a bad idea. If static information on the end-game statistics for several board sizes is the only thing that is desired for a Piececlopedia page, (accompanying a sentence that points out the piece has mating potential), it would be best to just hard-code that in the HTML. (The applet could still be used to calculate the required info before incorporating it into the page, of course.) There would be no need for a diagram in that case; the latter only serves the function of allowing interactive play.

If the applet would have its own page, it might be possible to set it up such that individual Piececlopedia pieces can link to it through some standardized link (saying something like "Practice checkmating with this piece"), in such a way that the page opens configured for the piece in question. (E.g. by passing the Betza descriptor for the move as a CGI argument in the URL.) We would have to pick a default board size, though. (8x8 seems the obvious choice.) The applet page itself could allow the user to alter the board size, within reasonable limits.

Of course not all pieces have mating potential. So deciding which pages should have a link to the applet should be done 'by hand'. This is probably necessary anyway, because the info for how the piece moves would have to be provided with the link. So all the Piececlopedia pages for pieces with mating potential would then have to be hand-edited.


Almost Grand, a very modest variant[Subject Thread] [Add Response]
H. G. Muller wrote on 2018-12-18 UTC

Although the official definition of 'modest variant' can perhaps be stretched a little, I don't think it should ever apply to variants like Grand Chess. With two extra super-pieces and a 50% larger board there is not much modest about it. (Or to its inventor? ;-) )

My own design Elven Chess is a Grand-Chess-like variant that uses crowned pieces rather than knighted ones. Next to Crowned Rook and Bishop it also features plain Commoners (which could be considered crowned pawns). Instead of a Centaur I used the Chu-Shogi Lion, however. Of which the Centaur is a sub-set, but which can also be considered as a King with extra King moves (but sequentially).

Crowned pieces are surprisingly impopular, in western chess variants. (In Shogi, OTOH...). BTW, the army you propose is mainly weaker because 'crowning' adds only 4 moves to Rook and Bishop, while 'knighting' adds 8. In addition the amazing synergy between B and N that beefs up the Archbishop value by nearly 2 Pawns is absent in the Crowned Bishop. And the Centaur is the weakest of the common super-pieces even on 8x8, and enlarged boards only makes this worse because of its low speed. So where the unorthodox pieces in Grand Chess have value 9.5, 9 and 8.75, in your proposal they have only 8, 7 and 5.25.


Joe Joyce wrote on 2018-12-18 UTC

If you read what Christian Freeling has said about Grand Chess, you might buy the argument that Grand Chess is one of the most excellent modest variants. Late night ideas - am writing a reply about Hannibal Chess, and got sidetracked to a slight variant of Grand Chess which I will have to exorcise before I can go to sleep. (Sorry, Kevin, I'll finish your reply tomorrow. ;) In considering what Christian thinks about his design, I came back once again to the idea that the piece set is not complete until you use the 3 king + rook/bishop/knight pieces also. So Almost Grand replaces the queen with the centaur (N+K), the archbishop with the dragon bishop (B+K), and the chancellor with the dragon rook (R+K), and all else is as Grand. This army is a little weaker than Freeling's, mostly from losing the ability to leap over adjacent pieces. Clearly it works for all the Carrera-Capa variants, and might actually help those games a little by toning down the power of the queen equivalents plus losing the archbishop's ability to checkmate without the aid of any other piece. I admit that after playing Grand Chess, playing Carrera-Capa made me feel claustrophobic!

Now this is such an obvious idea someone must have done it before. Can anyone point me to such a game?

 


Checkmating Applet[Subject Thread] [Add Response]
Ben Reiniger wrote on 2018-12-17 UTC

Initial thoughts (mostly the ones I had but didn't post a couple of months ago; sorry):

I like the tool a lot; thanks for creating and sharing.  For individual piece(clopedia) pages, I wonder whether something static would be better.  I think the whole table is a lot more in-depth than many of our piece pages, so maybe a summarized version (if necessary for a couple of board sizes?) would be a better fit for those.  (On that note though, I have at various times wanted to expand on and standardize piece(clopedia) pages...)  I think the entire tool itself would work well as its own page, maybe listed as Primary (so displayed at the top of searches) in the Piece(clopedia) page type?


H. G. Muller wrote on 2018-12-17 UTC

I still would appreciate some response from an editor on my proposal, even if it is just a firm rejection...


Cannon Movement[Subject Thread] [Add Response]
Aurelian Florea wrote on 2018-12-16 UTC

Yep,

It is all fine :)!


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