Ratings & Comments

Extending the number of ranks and files to infinity does not also increase the axes of movement through individual spaces. This is a large 2D game, but it is not 3D or 4D. So, I have removed it from those categories.

It should be the same as for rows/columns in 2d hexagonal games, right? (I'm not sure if we have a consistent policy for that...)

4d games are rare enough that I wouldn't have bothered to add a database column. It will probably cause confusion for new authors. But there's already reason to expound on the categories and index information on special cases, maybe as tooltips plus a link to a page describing non-obvious conventions?

The diagram on the page superficially resembles that of Sphinx Chess, but it has only two axes of movement, the vertical and the horizontal. If you follow the lines of movement of pieces on this board, you will see that multiple boards have been placed together to create a larger playing area on which pieces are still moving in two dimensions.

4d games are rare enough that I wouldn't have bothered to add a database column.

Since I was adding code to the footer to indicate a board's dimensions, it seemed more appropriate than treating them as 3D games.

It will probably cause confusion for new authors.

I have added tooltips to the Edit Item form, and if there are other forms they should be added to, I can do that. I have also used parentheses to make it clearer what the dimensions of a board refer to. For 3D boards, a single pair of parentheses go around the files-by-ranks part, and levels goes on its left. For 4D boards, another pair of parentheses goes around the 3D board dimensions, and the 4th dimension goes on the left. The convention I'm following places increasing dimensions on the left, and it treats the number of ranks as the first dimension. This is because in the typical Chess variant, the board has two sides, and each player starts with all his pieces on one side. So, the distance between two sides would be the number of ranks. The second dimension, the number of files, is about how much space each side has to spread out its forces. Since we normally write files before ranks in algebraic notation, it makes sense to add higher dimensions to the left side. Also, this was the convention followed in some 3D games I looked at last night. And it's also sort of how Arabic numerals work. The leftmost digit in a numeral has a higher value than those to the right.

Indeed, when WeirdPromotion() is used to pieces that would also promote otherwise it involves more than just returning the desired promotion piece. The Diagram makes a special call to it (recognizable by promo = 1021) to inquire whether there might be promotion choice, and in the passive burning case this should be used to suppress the choice that maxPromote and promoZone would suggest. I don't think the current version does this entirely correct for Shogi promotions, though. I will have a look at it tomorrow.

When representing a 4D game in two dimensions, which is what we're limited to on a computer screen, it makes sense to pair together a higher-dimensional label with a lower-dimensional one. This is especially so with something like Game Courier, which gives you only files and ranks to work with. This can lead to a coordinate like Dc23, which I hovered over randomly, which transposes the second and third dimensions. Bearing that in mind, it looks like this game has 5 ranks, 5 files, 5 3D rows or levels, and 5 4D columns or realms.

The queen and wizard don't slide then, correct?

Checkmate might be rather difficult here, but I haven't thought too much about it; the pieces are weaker than many 4D variants, but it's also a very small space.

Note that the knights cannot reach the centermost square. I was wrong here, see subsequent comments.

I cannot use the item quick-edit script (as an editor) because the form does not have the new BoardRealms input (though perhaps the quick edit can be deprecated now that the author list population isn't so slow), and the database apparently won't allow it to be null. Again, I really think allowing nulls for non-game items would be best, and BoardRealms should be defaulted to 1 in any forms.

I'm thinking of making Masindam puzzles soon !

Fergus wrote:

"... it looks like this game has 5 ranks, 5 files, 5 3D rows or levels, and 5 4D columns or realms."

Yes, I suppose it could be put that way.

No, rules 2-3 means that pieces cannot move from one "domain" to another except as in a 4d (asymmetric) game.

But it does look like I may have been wrong about the title: the domains are each infinite, while apparently the domains are supposed to be limited to an 8x8 grid.

"This rule gets rid of zugzwang." 
 
More than sixty years ago I learned how to use zugzwang to win with King and Rook against the lone King. So how does Tony Berard deal with this problem? 
 
"The rooks, bishops, and knights now also move and capture like a king." 
 
Sixteen years ago I commented on Ultra Chess (by Ruggero Micheletto).  Here is a question for both authors.  Is the endgame King and Rook versus King and Knight even more likely to lead to a draw in your chess variants?

@Fergus Have you any idea about what is going on!

Indeed, a user promotion choice does overrule everything else. If a fixed promotion is required for pieces that would offer choice, the promotion query should be suppressed. Not only because it would prevail, but because it makes no sense at all to let the user choose and then do something else.

The mechanism the Diagram uses for this is to call WeirdPromotion() with the promo parameter set to 1021 (which is not a valid piece type), to inquire whether there is promotion choice. When this call returns 1001 the query will be suppressed, when it returns 1000 a query is forced, and in any other case it decides itself (based on maxPromote, promoZone and promoChoice).

In the AI it works slightly different; there (for a piece that could normally promote) WeirdPromotion() is called with promo equal to the promoted piece (as per promoOffset), and to suppress the promotion this would have to return 1022. It is the deferral (promo=0) that must be turned into a kamikaze move by returning 251, so that moves that would not naturally promote also get burned.

So when a passive burn is detected, WeirdPromotion() should return 1001 if promo == 1021, 251 if promo == 0 and 1022 otherwise.

Yes, I was thinking that we no longer need the quickedit script. It was made back when I was still accessing the site through dial-up. Now that we're all using broadband, dial-up speeds are no longer a bottleneck. Besides that, I have since reduced the size of the edititem script by replacing four separate but identical drop-down lists with a single datalist that gets used by four different fields.

update test

the knights cannot reach the centermost square

Afaict the second part of the N's move is optional here, so it may make one‐step orthogonal moves and thus access the central square if needed. So it's more a Rhino than a traditional Knight

I did not realize that when I thought of Stone's chess. Assumed that Janus chess had castling that left the king in a similar position to normal chess. Thanks for pointing it out!

Afaict the second part of the N's move is optional here[...]

Ah, you're absolutely right.

This Diagram lets the Queen burn both actively and passively. It uses trackPieces=1 to track the Queen, so WeirdPromotion() can efficiently get her location, and mark the adjacent squares as the burn zone, to destroy all pieces that land there.

(Refresh the browser cache, as there was a bug in the standard script w.r.t. kamikaze moves: these did set the 'non-virgin' flag on the resulting empty square, so the Diagram would treat it as an invisible white piece rather than an empty square. For now I solved that by making all pieces resulting from promotion virgin. Which is of course incorrect, but much less harmful.)

DIAGRAM WITH REDUNDANT ROOKS

Here's an alternate setup, similar to TenCubed Chess. The Archbishop (e1) defends the Knight (c2) which protects a Pawn (a3) and a Rook (a1). After the Knight has moved, the Archbishop may take its place on (c2). The Chancellor has much the same story. Note that the Queens are now on their own colors. My personal preference is placing the Rooks on the second rank and something exotic - like Cannons - in the corners. With your Rooks in the corners, you are free to try new pieces on (b2) and (i2). Silver Generals would provide a rock solid defence of the Pawns - perhaps too solid.

[EDIT] This arrangement of four Rooks was actually used in Colossus - Charles Daniel (2010).