This is a variant combining the character of several existing variants. Ten basic rules distinguish it from FIDE Chess, although other implied rules result from combining them. The board has ten ranks and ten files. The array has ten kinds of symmetric piece, ten kinds of capturable piece, and twice ten individual non-compound pieces aside. Taking both armies together there are ten individual pieces in each of three groups modelled on the familiar Rook/Bishop/Queen group, although there is a fourth dissimilar group with more. Therefore I contend that it is highly suited to marking ten years of the Chess Variant Pages.
The variant differs from FIDE Chess in the following ways, derived from three existing variants on these pages:
From WILDEBEEST CHESS:
(1) Pieces other than steppers are grouped as two aside in each of a pair of dual directions, plus one aside of their compound. The long-range FIDE pieces form such a group.
From ANGLIS QI:
(2) Compound pieces must remain on their own side of the River, which is the boundary between the middle two ranks. In the King's case this is an Anglis Qi AND Eurasian Chess rule. Applied to all compounds, it means that three otherwise strong pieces cannot capture each other or give check.
(3) Pawns crossing the River become Wazirs, and can retreat again without reverting to being Pawns.
(4) Because of this swift promotion there is no initial double step and therefore no en passant.
From EURASIAN CHESS
(5) The board has 10 ranks and 10 files, with the King, Queen, and Rook positions that Eurasian Chess shraes with Grander Chess. Whether ranks are numbered 1 to 10 or 0 to 9 is a matter of style, and has no bearing on how the game is played.
(6) A piece starting as a Pawn may, after a move finishing on an end rank, be further promoted to a stronger piece captured by the enemy.
(7) Pieces of the "Chinese family", in the style of the Xiang Qi Cannon, are included.
(8) Kings cannot occupy the same file or diagonal without an intervening piece.
Two further differences are:
(9) Whatever I do with castling on a ten-file board (including having none at all) necessarily differs from FIDE. I have adapted the rule from Ecumenical Chess, another Wildebeest offshoot of mine. Castling requires that the King has not left the middle two files, the Rook involved has not left its own and the adjacent file, neither has left the back two ranks, and both are on the same rank with no intervening piece. They move towards each other within that rank, the King to the Bishop file and the Rook to the Camel file. The King may not castle into/out of/through check OR bare facing. Some day I might do an Ecumenical Eurasian Qi, perhaps for the long-promised 169-cell contest!
(10) There are gaps in the Pawn rank. This is intended to give exactly 24 pieces aside, for ease of physical representation. It does however give the bonus of restoring a Xiang Qi feature lost in Eurasian Chess: Knights are en prise to Cannons, but only at the cost of Cannons immediately putting themselves en prise to Rooks! Camels are also on the vulnerable side but start off highly mobile.
Combining these differences results in:
(A) Rules 1 and 7 mean that there are an even number of non-Pawns, suiting an even number of files, with Cannon-style counterparts for Rooks, pale-cell Bishop, dark-cell Bishop, AND Queen.
(B) Rules 1 and 2 mean that that last compound and the Gnu cannot cross the River.
(C) Rules 3 and 6 mean that it is Wazirs that get promoted to captured pieces, by a move to OR WITHIN either the enemy end rank OR THEIR OWN, and that there is no restriction on them reaching such ranks if no suitable piece has been captured.
(D) Rules 1 and 6 mean that there is are potentially nine kinds of piece to promote Wazirs to, three of them compound.
(E) Rules 2 and 6 mean that compound pieces can be recovered only by promoting Wazirs on their own end rank, which is actually the longer trek.
Here is the full piece list with their moves and recommended equipment. Two standard sets easily distinguishable by size should be used.
Steppers, 9 aside, 18 on board altogether:
PAWN: the familiar Occidental front-rank piece, surviving from Chaturanga right through to Wildebeest Chess and Anglis Qi and now to this combination. Moves one step forward at a time, diagonally if capturing otherwise orthogonally. The eight Pawns aside are represented by Pawns from the small set. Pawns can form chains on their own side of the River, but after crossing it a Pawn becomes a ...
WAZIR: not an array piece, but the result of a Pawn crossing the River. Moves one step in any orthogonal direction. There can be up to eight Wazirs aside, and while the full complement is unlikely you may well have three or more at a time. Therefore they are represented by Pawns from the large set. When ending a move on an end rank, it can be promoted further to a captured piece, though not a compound one on the enemy end rank.
KING: the familiar Occidental ruling piece, surviving et cetera et cetera. Moves one step in any radial direction. Must be kept out of check, with checkmate and stalemate as per FIDE Chess, plus the bare facing rule from Eurasian Chess. The one King aside is represented by the King from the large set.
Linepieces, 5 aside, 10 on board altogether:
ROOK, BISHOP, QUEEN: the familiar FIDE long-range pieces, and in the familiar numbers. Bishops are confined to cells the same colour as their starting ones. The only oddity is that the Queen cannot cross the River. All are represented by the obvious pieces from the large set.
Hoppers, 5 aside, 10 on board altogether:
CANNON: added to Xiang Qi following the invention of gunpowder to strengthen the array. Moves exactly like a Rook, except that when capturing it must pass through exactly one occupied cell - plus any number of unoccupied ones including zero. The intervening piece is NOT itself captured, and can be friend or foe. A Cannon checks if it is an orthogonal line with the enemy King and separated by exactly one intervening piece. Note that a Cannon cannot capture or check an adjacent piece. The two Cannons aside are represented by Rooks from the small set.
ARROW: first invented for fairy problems, but taking its place as a full-game piece courtesy of Fergus Duniho, who gave it this name and used it in Yang Qi and then in Eurasian Chess which was a development thereof. Moves like a Bishop, including confinement to cells of one colour each, but again must pass through an occupied cell as per the Cannon. The two Arrows aside are represented by Bishops from the small set, reflecting its relation to the other long-range pieces. The choice of image in this text is one widely used for diagonal pieces, including the Timur's Chess Picket which like this piece cannot capture or check an adjacent piece.
TANK: the compound of Cannon and Arrow. My choice of name is an attempt to follow Dr. Duniho's precedent of Arrow by conveying the sense of a powerful but mobile projectile launcher. Moves like a Queen, including inability to cross the River, but again must pass through an occupied cell et cetera. Tanks are initially blocked by two pieces in every direction, and are Kingside to balance the Queen. The one Tank aside is represented by the Queen from the small set, reflecting its relation to the other long-range pieces and also alluding to the comic-strip heroine Tank Girl.
Leapers, 5 aside, 10 on board altogether:
KNIGHT: the familiar Occidental 2:1 leaper et cetera. Cannot be blocked by an intervening piece. In this variant Knights are initially trapped by Pawns and Arrows, encouraging the development of those pieces. They are also en prise to Cannons, but covered by Rooks. The two Knights aside are represented by the Knights from the small sets.
CAMEL: the colourbound dual of the Knight. The Camel's 3:1 leap is equivalent to two Knight leaps at right angles. This piece too cannot be blocked by an intervening piece. Camels are initially mobile, and just as well as an enemy Bishop moved to the right place will threaten them. The two Camels aside are represented by the Knights from the small set, reflecting its having only one move per direction like the Knight and its "Light Cavalry" label in Napoleonic Chess.
GNU: the compound of Knight and Camel. Cannot be blocked except by the River, which it cannot cross. In this variant Gnus begin very mobile. The one Gnu aside is represented by the King from the small set, reflecting its having only one move per direction like the King.
Full front rank, with two Wazirs and eight Pawns, bar on exceeding eight Wazirs explicit rather than implicit.
Dropping castling, or using the Grand or Grander Chess rule. Conversely applying Wildeurasian Qi castling to those variants or to Eurasian Chess might give an interesting variant.
Arranging the back two ranks differently. If this variant generates as much comment in the issue as Grand Chess I will feel very flattered!
Korean-style: Cannons, Arrows, and Tanks require an intervening piece, and the front rank are Wazirs from the start.
Pawned Wazirs (aka Stewards, Fusiliers, &c), Goldgenerals, or Silvergenerals as the intermediate promotee, or even a choice between them, although the latter would violate easy physical representation.