GOLDCHESS and SILVERCHESS
Charles GilmanIn many variants moving is easier forwards than backwards, for back-rank pieces as well as Pawns. These include Feebback Chess, Forward Chess, and different-armies variants using the Forward FIDEs. An extreme example is Checkers Chess, in which pieces have no backward move (and possibly no sideways one, depending on interpretation) before reaching a promotion rank. All these start with substitutes for the FIDE pieces in the same proportions and positions, and so do not really need illustrating with array diagrams. This is in contrast to the greatest forward-biased game of all, Shogi, which has a board all of its own.
Goldchess and Silverchess use the distinctive direction combinations of the Shogi generals (5 for Silver, 6 for Gold), replacing the linepieces with extensions of the generals as listed in Generalised Generals and the Knight with corresponding oblique pieces from the final and largest section of When Beasts Collide. They retain FIDE moves in relevant directions, gain short-range moves in remaining relevant directions, and lose them in unused directions. As is common in near-FIDE armies, Pawns and Kings are standard. Pawns remain the only divergent pieces; all moves by first-rank pieces can be either capturing or noncapturing.
Replacing the Rook is a GOLDROOK in Goldchess, and a SILVERWING in Silverchess. The Goldrook is a Rook enhanced by the two forward Ferz moves. The Silverwing conversely is clearly weaker than the Rook, with all the Ferz moves but a long-range move on only the forward orthogonal.
Replacing the Bishop is a GOLDMITRE in Goldchess, and a SILVERBISHOP in Silverchess. The Silverbishop is a Bishop enhanced by the single forward Wazir move, which by unbinding the Bishop is a greater enhancement (though still to a weaker piece) than from Rook to Goldrook. The Goldmitre gains and loses relative to the Bishop: it loses long-range backward moves, but gains unbinding through all four Wazir moves.
Replacing the Queen is a GOLDRIDER in Goldchess and a SILVERIDER in Silverchess. Each rider is a Queen restricted to the directions of the corresponding general, and clearly weaker than the Queen itself.
Replacing the Knight is a NITAN in Goldchess and a CAMAN in Silverchess. Pronunciation may be deduced from their being abbreviations of "Knighted Handyman" and "Camelled Handyman", Handyman being a forward-only compound in From Ungulates Outwards. Each has ten moves: the Nitan the Knight's eight and the two forwardmost of the Camel and the Caman vice versa. As the Nitan has more cells from which all ten moves are available, and can triangulate e.g. b1-c4-a3-b1, I estimate that the Nitan is 30% stronger than the FIDE Knight and the Caman only 20%.
In the basic game, Pawns can be promoted to any part-symmetric array piece. However there is an alternative rule of CROWNING or JEWELLING, promotion of ANY capturable piece reaching (or passing) six files forward of its starting square. Rook and Bishop substitutes are respectively promoted to the CHATELAINE (Rook+Ferz) and PRIMATE (Bishop+Wazir) of Constitutional Characters. Queen substitutes are promoted to the Queen itself, and Knight substitutes to the GNU. Pawns can be promoted to any promotee. Two sets distinguishable by size could be used, the small set for array armies and the large for promotees. This promotion system can also be applied to the FIDE army itself (echoing Shogi promotion), except that the Queen too is unpromotable (echoing my own Bishogi).
There are several other options worthy of note within this page though not in the same detail as the main game.
PEDES INCLUSIVE: Goldpawns and Silverpawns can make the noncapturing orthogonal moves and capturing diagonal moves of the corresponding generals.
REX INCLUSIVE: Goldrulers and Silverulers are royally-restriced forms of the corresponding generals, promotable to King on the enemy Pawn rank.
CROWNED or JEWELLED CHESS: starting with a King and Queen and two each of (going outwards) Primate, Gnu, and Chatelaine. This is an outright enhancement of the FIDE array, comparable to Cavalry Chess.
IRONCHESS: A forward-only (except for the King) array with a PRINCESS and two each of ABBOT, HANDYMAN, and CARYATID. These have the forward moves of - and are promotable to - Queen, Primate, Gnu, and Chatelaine respectively. Promoting only Pawns would be unworkable, although promotion to the Gold or Silver pieces (gilding, plating?) is another option. Note that (1) Pawns already conform to the radial directions used; (2) paired array pieces are stronger than those of Checkers Chess but weaker than FIDE ones.
COPPERCHESS: Ironchess with the backward orthogonal added. As pieces for this is outside the range of my current and planned piece articles I do not have names for them all!
Can the theme be extrapolated to Cubic boards? The main obstacle to SUNCHESS, MOONCHESS, COASTCHESS, SKYCHESS, and the like (see Generalised Generals again) may be finding players who can keep track of all the moves! One feature that would help in 3d would be promoting standard linepieces in all-radial variants such as many forms of my Tunnelchess, by adding a short-range move in the remainder of the 26 radial directions, to help make checkmate easier. Combinations not using the standard diagonal could however be applied to a hexagonal-cell 2d board as BRASSCHESS and AZURECHESS. I have terms for all the radial pieces but not yet for root 7 and root 21 combined leapers. It may be best to stick to the plain root 7 leaper standard to hex variants, which I term a Sennight.