8x8 Capablanca engines needed.

[Matthias Gemuh]

It is just normal chess but with 2 more promotion pieces:

Archbishop moves like Bishop+Knight.
Chancellor moves like Rook+Knight.

Games in which an engine promotes to one of these tactical pieces instead of Queen occur quite frequently.

I hope you will at least think about implementing this variant.
You can watch ArcBishop and Chancellor play it in ChessGUI.

Best regards,
Matthias.

[hgm]

Is this a useful variation on normal Chess? Promotion to Queen almost always decides the game, so what would be the point in promoting to A or C (which are slightly less powerful)? The cases where you can only win by promoting with check along a Knight's leap (and therefore chosing C over Q) seem extremely rare to me.

I guess you could play this against fMax, after renaming the game description that is now called 'normal' to '8x8_capablanca' in the fmax.ini file. fMax is not very critical w.r.t. the piece you promote to, in all the descriptions I included in the fmax.ini I always define all 14 piece types. So in edit mode it does accept all pieces always (for tnow it just has a fixed translation from piece name to internal code; I will make this definable from the fmax.ini at in some future version).

It searches only promotions to Q, though. Even in Capablanca Chess and Gothic Chess. That does not stop it from giving ArcBishop and Chancellor a quite heavy beating in those games (it scores between 85 and 90% against them). I have not looked at the few games where Chancellor and ArcBishop scored points, to see if any of those were due to fMax being surprised by underpromotion to A or C, but I would be surprised if there were any.

So fMax would allow its opponent to promote to A or C (or E, F, W, M, if you wanted ), and would accept and anticipate all later moves with these pieces. But it would never promote to one himself. And it would be hardly handicapped by this.

[Matthias Gemuh]

It (i.e. Fairy-Max) searches only promotions to Q, though. Even in Capablanca Chess and Gothic Chess. That does not stop it from giving ArcBishop and Chancellor a quite heavy beating in those games (it scores between 85 and 90% against them). I have not looked at the few games where Chancellor and ArcBishop scored points, to see if any of those were due to fMax being surprised by underpromotion to A or C, but I would be surprised if there were any.

In view of these objections, I suggest that no other programmer should implement this chess variant. Apart from ArcBishop, some future versions of BigLion and Taktix shall play it. That should be enough for the chess community.

Best,
Matthias.

[hgm]

It would still be interesting to play it starting from a setup position, where A or C would be present in the initial array (e.g. play with A in stead of R, or C in stead of Q).

If you are looking for other variants, you could try Janus Chess, which features two Archbishops on 10x8 board.

Note that WinBoard_F allows the name of ANY variant to be preceeded by a defiant board size, e.g. 9x9_normal. This can also be selected from the menus, when you select a new variant, by overruling the default height, width or holdingssize. If you change the boardWidth, it won't know a default opening position for it, though, and you will start with an empty board on which you will have to paste a FEN.

So you can play a Capablanca Crazyhouse by setting the holdingssize to 7 while selecting variant Capablanca.

People are encouraged to implement that feature in their engines.

[Matthias Gemuh]

It would still be interesting to play it starting from a setup position, where A or C would be present in the initial array (e.g. play with A in stead of R, or C in stead of Q).

Yes, that is a reasonable option.

If you are looking for other variants, you could try Janus Chess, which features two Archbishops on 10x8 board.

I will do that. Just one last question: aren't we polluting chess with all these variants ?

Best,
Matthias.

[Ovyron]

aren't we polluting chess with all these variants ?

No, chess variants are great to have just in case you get bored of chess and need a break. But you still want to play something chess like, so you can play a chess variant entirely for fun (Without having to worry about the openings, or the rating, or analyzing your games.) So the more chess variants the better

[hgm]

Seirawn Chess is a good variant with Capablanca pieces on an 8x8 board:

In this game you start with A and C 'in hand', and you are allowed to drop them on the square just vacated by a virgin Piece (not a Pawn).