Comments/Ratings for a Single Item

I have rewritten most of this page with updated information from Jean-Louis Cazaux's excellent new book A World of Chess, co-authored with Rick Knowlton. The previous version had the initial setup incorrect (both of a player's bishops on the same color) and incorrectly identified the author of a book on chess variants as the game's inventor. Additional historical information has also been added.

I still need to make a similar revision to The Emperor's Game

Ok, I updated this page in the manner I would propose for general usage. Everything seems to be ok, except that after you move one of black's pieces, the color of the dark squares changes to a gray and stays that way.

OK, that looks good. Except for those with JavaScript switched off.

To cure that there should be a static image as alternative (screenshot?), in <noscript> tags. Perhaps together with a message that points out what they are missing):

<noscript>
<p>You can play against this diagram if JavaScript is on</p>
<img src="....">
</noscript>

And you can add display:none; to the style of the <div> conaining the interactive diagram; the betza.js script would make it visible when it converts the deinition to a board image, and it keeps the definition hidden when JavaScript is off.

The color change is by design. Should really happen on the first click already. This can be suppressed by using darkShade instead of startShade to set the color. Bright colors are often not ideal for playing, especially when colors were used for highlighting. But some diagrams use dark-blue squares, which even camouflage the 'black' Alfaerie pieces.

Changing startShade to darkShade does not seem to have worked.

I added the noscript section. Good call.

Changing startShade to darkShade does not seem to have worked.

Because it has not been changed. Check through 'Show Page Source'. The caching is screwing up things.

[Edit] OK, with ?nocache=true it does seem changed, and indeed it does not work. I will check it out.

[Edit2] OK, should work now. It was interaction between the two diagrams (the one in the Comments is on the same page), where one remembered the 'realColor' of the other. Which was not reset, because startColor and darkColor were not both defined in this diagram. I moved the initialization of realColor to an invalid value from the globals to the routine that parses the diagram definition now.

There is a typo in the German book title, it should read "seine" in place of "siene".

Also, I read the author's name as "Tressan" in accordance with Google OCR. There is a clear bridge between the two stems on the upper part of the last letter of his name. Google search finds the name on several pages where it seems to be removed from the pictures (Probably from bottom lines for the bookbinder, called Bogensignaturen in German language).

I have found the book on Google books here: https://books.google.de/books?id=n64UAAAAYAAJ&printsec=frontcover&hl=de&source=gbs_ge_summary_r&cad=0#v=onepage&q=Tressan&f=false

P.S. Can we complete Peguilhen to Ernest-Frédéric von Lavergne-Peguilhen (1769–1845), recipient of the last letter from Henriette Vogel and Heinrich von Kleist? Life dates and occupation are fitting, and he also went simple by Peguilhen.

Thanks, Jörg! These corrections have been incorporated.

Thanks Greg. Can you update the Emperor's Game as well?

I only notice now that these variants have weird castling rules, where the Rook doesn't end up next to the King. At the moment the diagram doesn't support that. Also for lack of a Betza notation for this. The On castling implies the castling partner ends on the opposit adjacent square.

[Edit] For now I solved this problem by allowing additional specification of the castling type through diagram parameters, rather than introducing new XBetza notation. For this I implemented a new parameter castleGap, default value 1, which corresponds to normal castling. The idea is that for castleGap > 0 the destination of the Rook will be that of the King, minus castleGap times the basic King step. For castleGap=1 the Rook would thus end up next to the King on the inside, while castleGap=2 would leave an empty square between R and K, etc. If castleGap < 1, however, the reference point  is the King's square of origin, instead of the destination. That means that castleGap=-1 gives the type of castling we want here: the Rook ends next to the square where the King started (just as the King ends next to where the Rook started, so that they move by an equal amount.)

In fact, the rook - both here and in the Emperor's game - does end up next to the king. After Tressau's (and I believe this is the correct name, not Tressan: see Oettinger’s Bibliotheca Shahiludii) rules for the Sultan's game, K moves four squares towards R which lands on the adjacent square. Check the illustrative games in Tressau's book. I have a paper in press in the Board Game Studies Journal dealing with the Emperor's game and the Sultan's game which I hope will be published in 2022; will provide a link when it is.

When saying ‘four squares’, is that counted inclusively or exclusively? In the former case, both king and rook moving ‘four’ squares each would in fact land next to each other, on the bishops and adjutant's squares on the queenside and the marshall's and knight's on the commanderside.

K to b/j, R to c/i.

Is that Tressau's interpretation? And do we know how much info the original sourcs gives on the matter?

After all if the latter does specify, as this article does, that both pieces move four spaces each, the Kc/i–Rd/h interpretation would make sense both in terms of preserving usual castling and lining up with the frequent use of inclusive counting (see also paragraph 4 of the Comments in Cazaux' page on Grant Acedrex)

Tressau does not explicitly mention how many spaces the rook goes, but the landing square for R in the Sultan's game is obvious enough from the provided illustrative games: see mating position in game 1 (p. 87) and move 28 in game 4 (p. 89). [On move 20, White castles "to the right"; move 28 is Ri1-f1, or 119 to 116 in the original notation; that's the first R move after castling].

Ok, having actually gone to find a copy online, I agree that Tressau specifies the Kb/j–Rc/i castle; in principle one could still object that the example games may not be played by the original rules (while he says they're real, rather than constructed, games, it could still be under the influence of a misunderstanding), but it seems upon a cursory reading that for the Sultan's Game in particular his book may in fact be the original source? The Emperors Game is cited in the Spielarchiv, but Tressau explicitly notes (p.80) that a game with a Marshal had been suggested there but not described, rather being rejected due to the necessary odd number of files being unwieldy (in particular due to either same‐colour bishops or transposition of one bishop but not the other with its adjacent knight).

Unfortunately a quick search for the Archiv der Spiele online appears entirely fruitless so I can't confirm that…

Tressau modified the rules for the Kaiserspiel (e.g. castling rule is different in the Archiv der Spiele description) and practically developed the rules for the Sultanspiel himself based on Peguilhen's initial - but never fully developed - idea. Later sources are ultimately based on Tressau, with errors. Thus it's Tressau's rules that should be taken as definitive, the illustrative games were played by Tressau himself and after his own rules, so there is hardly any chance for a misunderstanding. There's a discussion of all that in my paper in press, I'll provide a link when it's published.

Indeed, that was my impression from his book as well; I'd initially missed the detail of how recent this variant was and had assumed it significantly older (and I don't trust people to count like we do today(!)).

I enjoyed the other papers you posted here and look forward to reading this one too

Thank you very much indeed!

Meanwhile, I realized I seem to have somehow misread your "search for the Archiv der Spiele" as "search within"; I hope this link works: https://books.google.bg/books?id=If5dAAAAcAAJ&printsec=frontcover#v=onepage&q&f=false

Like Georgi Markov, I confirm that I believe that the name of the cited author is Tressau and not Tressan. Maybe the text of this page should be corrected, also because my book is cited (thanks). In this book, we used Tressau.

That being said, the gothic script which is used for the original German book is not easy to distinguish an "u" from an "n".

Maybe the text of this page should be corrected, also because my book is cited (thanks). In this book, we used Tressau.

Yes, sorry, this was a mistake.  I changed the name on the Emperor's Game page when I updated it but overlooked making the same change here.  I'll get it corrected.

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.

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.)