Ratings & Comments

I configured it myself. It is possible to train an NNUE for a custom variant for Fairy-Stockfish, so if someone were to do that, we could probably have much better version that should understand the value of the pieces and king safety properly. Unfortunately, I do not have the hardware to train it right now.

I wonder if it would be worth it to support mandatory capture in the Interactive Diagram. Removing all non-captures from the move list if there is a capture in it would not be that difficult. If that doesn't leave any move (which normally would indicate the side to move is mated), it could undo that, so the search can use non-captures. I have no feeling what this would do for the piece values, though. And it would only work if the rule applies to pseudo-legal captures. (Which would be fine for games like Suicide Chess, which do not have royalty in the first place.)

If non-captures would be allowed when pseudo-legal captures are possible, but all illegal, it would be a bit harder. Whether a move is legal would only become clear after searching it deep enough to see the replies. I guess it could start the same way, though, suppressing all non-captures in the first few depth iterations it does for each position. If at the depth where illegality of captures can be seen no legal moves remain, it should get a second chance to re-enable the non-captures.

Of course we could try to generalize the rule and refine it, by allowing type specifity. E.g. a new symbol in the captureMatrix could indicate which captures are mandatory. Then you could define f.e. pieces that must be captured whenever the opportunity arises ('Sirenes'?), or pieces than must capture whenever they can ('Maniacs'?).

Ah, I see. Define different Pawns for each side of the River, and if X is the piece ID of the fsW type write on the line below the definition of the fW type morph=X/X/X/X (meaning it morphs into X on the furthest 4 ranks). Then convert the Diagram definition to GAME code.

Note that King + Bishop are not able to force stalemate, but that giving the Bishop a single extra non-capturing orthogonal step is already sufficient to genreally achieve this.

Also note that the black King should play an active role; it should not be afraid to move to the centre, together with the pack of Knights. If the engine would use the standard king-safety evaluation, which strongly encourages it to cower away in a corner, and then keep a number of Knights there, and the best black can hope for is a draw. Instead black should go for the enemy King, and force the Queens to sacrifice themselves for a single Knight in order to pervent being checkmated.

OK, I see. This seems more about an issue how a mime piece that can be selected from a menu in a particular piece of software should behave to be most generally useful than a discussion about chess-variant design. In such configurable software the solution I discussed with Aurelian seems more flexible (and in fact upward compatible) than any of the options in the poll: allow the user to define an arbitrary mapping similar to the capture matrix between moved piece and what the mime should move as. The promoChoice strings could contain a newly defined special symbol to indicate "as the last-moved piece can promote". This decouples move mimicking from promotion mimicking.

I’ve recently seen a YouTube video with game between Levy Rozman (aka GothamChess) without his Knights VS Hikaru Nakamura with 7 Knights. Hikaru won, but it’s partially because he played by White and Levy blundered his Bishop on 4th move.

Maybe Bishops’ pair & 2 Rooks are better than 2 Queens.

The poll was on a Discord server.

Wiibid

But with shuffle.

Longest Stalemate Victory with K+N+(AmD) vs K

in 36 moves on the 8x8 board (98.8%)

in 55 moves on the 12x8 board (99.4%)

in 61 moves on the 10x10 board (99.4%)

The Checkmating Applet brings good news! My original creation, the (AmD) Elephant, can team up with a Knight to (eventually) stalemate a lone King. Pieces with four noncapturing moves are unusual in chess variants - the earliest examples I can recall are the Steward (quadra-pawn) in CENTENNIAL CHESS (1999) and the Bishop in Caïssa Britannia.

Knight and Ferz are another effective team, on the 8x8 board they can stalemate almost as quickly as the Knight and Bishop can checkmate. I was aware that a pair of Knights could force stalemate, but it is nice to have it verified.

Longest Stalemate Victory with K+N+F vs K

in 35 moves on the 8x8 board (94.4%)

in 55 moves on the 12x8 board (92.9%)

in 61 moves on the 10x10 board (93.6%)

Longest Stalemate Victory with K+N+N vs K

in 26 moves on the 8x8 board (99.5%)

in 37 moves on the 12x8 board (99.7%)

in 38 moves on the 10x10 board (99.7%)

Note that the percentages you quote are for the strong side to move, and for the checkmating almost exclusively reflect the number of immediate King captures. If the King cannot be captured in the first move, so that the weak side gets the opportunity to move, the winning chances on 8x8 have already dwindled from 27.3% to 1%. The long lines all stay within those 1%.

I don't know if Fairy-Stockfish is any good at this? Does it include this as an officially supported, highly optimized variant, or is it something you configured yourself? I know that the ordinary Stockfish many years ago was terrible at this. I let it play against QueeNy (a derivative of the 2400 Elo engine Spartacus), and it got totally clobbered. Engines that do not know 2 Knights are far more valuable than a Queen will play like an idiot. You cannot expect engines that blunder away their Knights to have any success in playing with black. Can Fairy-Stockfish beat QueeNy?

The author, A. M. DeWitt, has updated this page.

Ultima introduced a lot of novel mechanics for a chess game, some original and others from other games. To be honest, these novelties are a more valuable contribution to the Chess Variant world than the actual game in my opinion

If you actually play the game, it's clear that it can be quite flawed, in many cases due to overcomplications in the application of its rules. The inventor itself has even written an article about this.

Despite its flaws, it's clear that Ultima has something going for it, and I believe it was ultimately a net positive for the Chess Variant world.

I am working on a Piece Lab where you can test pieces of your own design. It really helped me when I first made a local one for my own variants, so I thought I'd make one for the general Interactive Diagram-using public.

Thanks!